When we committed to installing an air source heat pump (ASHP), we had reservations whether it would heat the house sufficiently. At the same time, we wanted to move away from oil so that we could be more sustainable and reduce our carbon footprint. So we took the plunge.
There are a lot of naysayers when it comes to air source heat pumps. Most say that they’re not good enough to heat homes in the UK over winter because it’s too cold and wet.
Throughout spring and autumn, our ASHP operating costs were much cheaper than oil. The real test was always going to be the winter when there was less heat in the air and where the pump has to work harder.
Luckily for our review, we had an awful December and January that was cold and damp; the worst weather conditions for ASHPs to operate in.
In the video below, we provide an honest verdict on whether we think that ASHPs are effective, efficient and sustainable in the United Kingdom.
It’s obviously worth noting that each air source heat pump is different. We have an 18kW unit from Global Energy Systems, a British manufactured pump, and results may vary from the size of your pump to the make/brand. We have not had an air source heat pump before, so we have no point of reference.
In fact, if you have an air source heat pump in the UK, I’d be very interested to hear your thoughts and feedback, and how it compares to ours, so please leave a comment below.
Consumption highs and lows of our air source heat pump
January 16, 2020, was our warmest day by average at 7.4C over the course of the winter. The coldest was January 20, 2020, at 3C. Relative humidity throughout January hovered at the 40% mark.
On January 16, 2020, we used 53.2kWh electricity (95% for central heating and 5% for hot water) to drive our air source heat pump.
By comparison, on January 20, 2020, the colder day, we used 66.6kWh (95% for central heating, and 5% for hot water).
So we used an extra 13.4kWh to heat our house when it was approximately 3.4C cooler outside. This is not insignificant from a running cost perspective over a long cold spells. The financial costs will add up. If you are going to solely use electricity to drive your central heating, that is some interesting data right there.
But that doesn’t tell the full story if you’ve got a solar PV array. The reason why it was warmer on January 16 was because it was overcast and rainy. So we produced virtually no solar (it was less than half a kilowatt hour) but the clouds didn’t allow the heat to escape.
January 20, however, was a lot sunnier and our solar PV produced 18kWh of electricity – we had to buy in 70kWh. On January 16, we had to buy in all our electricity as we produced close to zero, which was over 80kWh.
| Date | ASHP | Solar PV | Average Temp |
| Jan 16, 2020 | 52.3kWh | 0 | 7.4C |
| Jan 20, 2020 | 66.6kWh | 18kWh | 3C |
It therefore appears that with solar PV assistance, cold bright days are better suited for ASHPs, because they go a long way to offsetting electricity consumption.
If you’ve got an air source heat pump without solar you’re probably better off with more gloomy, overcast warmer days and nights that trap the heat because they’ll run are efficiently. At least that’s what our data is showing us at the moment for our pump and weather conditions.
It’s just an observation at this point, but over the course of the coming year I will look into this more closely and determine whether this correlation is accurate and precise.
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[…] UPDATE Feb 19, 2020: the winter review is available here. […]
[…] There are skeptics as to whether ASHPs can be effective in the UK. Check out our winter air source heat pump review. […]
[…] It’s been a year since the panels have gone up, and they have met our expectations. Our primary reason for installing a 6.16kW array was so that it could contribute towards the running costs our air source heat pump. […]
[…] we have managed to get renewable forms of heating (air source heat pump) and electricity (solar PV array), our next big projects for this year are going to be getting our […]
[…] Another massive difference between the ASHP and the oil boiler is that with the ASHP our heating in the cold months runs 24/7 versus limited timings on oil. We’ve covered this aspect before. […]
[…] on the path to sustainability with renewable heating, solar PV and our new veg patch, the weather has never been more important to us, so we’re very […]
Interesting.
Hi,
I watched your video with interest.
We have just built a house with underfloor heating and an air source heat pump. We moved in pre Xmas and the system has been struggling to get the house up to our target temp of 20/21 degrees.
There are three open fires and the “building regs” incoming air vents next to the fires which have been blamed for the systems performance. We have therefore blocked the chimneys and the vents.
Annoyingly the system still struggles to get the house up to tempreture when the outside air temp goes below 2 degrees and certainly below freezing.
In reality do houses with airsource systems need a secondary heating system in very cold weather? We have been told putting log burners in the three fires places would solve the problem and give us a secondary booster heat source in extreme weather.
I would welcome your thoughts.
With thanks
John
Thank you for your comments John.
Can you please let us know what size pump you have (and the brand), and how much space you’re trying to heat? Also, is it just rads or a mix of rads and underfloor heating? Do you know what the flow temperature is in your system?
In short, no, you should not require secondary booster heating with temperatures of 0-2C. We have just finished filming our next ASHP video that focuses very much on this subject. We see our house heating perfectly when it’s 5-6C outside. As soon as the temperatures start to drop below 3C, we notice a difference in the ambient temperature in some of cooler rooms, which we have put down to insulation, because the flow temperatures are still at 45C. Having said, we dropped to -5C a few days ago, and the house still remained at 21-22C, but we did consume about 85kWh on those days.
Since moving in, there have been a few milder days of 7-8C – did (or does) your house get to 20-21C and maintain these temperatures when it’s over 6C outside?
Hi we are now 2 months in to experiencing ASHP in our new build. (Underfloor ground and rads on first floor.) Initially we were a bit alarmed at the consumption of electricity but daily monitoring shows on milder days we use as little as 30kw with highest 69kwwhen it was minus 4 overnight. The house is being maintained at a comfortable 20/21 (it us 228 sq m). Our Grant Aerona system is 11kw.
If anything it is too warm upstairs overnight.
The aspect of the house is South at front so on sunny days front rooms naturally rise to 24 degrees in winter.
Overall our bills will be higher than normal mains gas/elec CH ystems but hopefully claiming the RHI grant will off set this for next 7yrs.
I would be interested in other ASHP users experience of annual maintenance costs/ advice of the system going forward. Do you think a maintenance contract is essential?
Sue
Hi, Interesting to see your experience . We have had a Ground source heat pump system for 10 years but the ground loop has developed a leak, the rate of which varies from top up every 3 weeks , to similar volume in 5 days. As regards performance the house has been kept at 20 C and the hot water at 48 C for the 10 years, the only issue was a 60 hour power cut due to severe snow fall wrecking the local distribution. Like you previously we had oil fired boiler which consumed >2000litres of oil and was on timer control. So we are considering changing to an air source . Your system is much larger than we are being recommended and I wondered what volume you were heating and are you like us just 2 people in the house 24/7. With the GSHP we installed cavity wall insulation and lots in the loft and it is a 7 kw system.
Good evening Edwin. Thank you for your message and comments. I am very interested to hear more about your GSHP and it’s maintenance, and I’d be happy to answer all your questions on ASHPs. Could I just one favour please? We’re transitioning as much of our ASHP and renewable heating conversations to Renewable Heating Hub, a new dedicated site that we have just launched to discuss all matters relating to renewable heating. If it’s not too much trouble, please can you register an account here and copy your paste your comment into a new thread: https://renewableheatinghub.co.uk/forums
I’ll be happy to walk you through it if you have any questions.
Sorry to hear this, it is not encouraging, for the millions of Victorian houses a and 30 and 40s houses. Seems it would involve expensive renovations. Electric boilers or even storage heaters sound a better option.
Electric boilers are not a sensible option for anyone, they have a CoP of just under one at all times so would cost far more to run than an air source even in cold weather, they are about 3 times as expensive as gas boilers to run.
Having a large victorian semi my accomodation and five bedsits, registered HMO. After much investigating dry lined the house internaly myself,kept the balanced flue gas wall heaters,some 40 years old,no maintenace cost and the two multipoint Brittony 11 gas water heaters,these last approx 25 years and can be refurbished. Have PV panels justified by generous initial feedback tarriffs. Sadly nothing else makes economic sense,ground source might if I was very young 🙂
We had a LG ThermaV split installed and I just could not understand why, when the temperature was way below target (say 16.5 versus 19 set) the HP was just taking it easy. When set to 19 continuously it coped with even the coldest weather but if we tried to have it at 18 during the night, it would take up to 24 hours to recover the temperature back to 19. But I think there is some strange interaction with the Honeywell wireless stat (which uses a sort of pulse modulation near to the set temperature). I eventually set up the Honeywell to pulse to 20 deg for one hour in the morning to spur it up into action after the 18 deg night time spell, and now it works fine. So what appeared to be lack of heat output turned out to a control problem that I still have not understood
Ideally you should not use a room stat at all, but instead setup weather compensation curve. i am not an expert but i think this uses the outside temperature to control your heat pump, kind of preemptively, rather than waiting for the outside weather to affect your room temp, and in tern your room stat.
Weather compensation should be the way to set up most heat pumps, but it’s not always possible to do so in retrofits.
[…] If you’d like more information on air source heat pump electricity consumption on cold sunny days versus warm overcast days during the winter you’ll find this post interesting. […]
This post reminded me of the heat pump I built from an old fridge, back in 1975, for my school physics project. Powered by a vertical axis wind turbine on the roof of the science block made from a halved chemical barrel and a car alternator, it warmed the science block in winter and cooled it in summer – after a fashion.
It would help to understand how large your house is and where. Maybe that’s back in the blog somewhere (I’ve not looked, sorry). I checked and my average daily (gas) heating and electricity in January 2020 was 65kWh (4 bed detached, 4kWp solar, UK west country). I have a larger than average electricity demand (my bad).
Thanks for dropping by Mark and leaving a comment. Your school project sounds very interesting.
We’re in the Welsh borders, and we’re heating around 4,000sqft.
Our electricity, over and above the ASHP, is a tad high and I’m fitting smart plugs to find the culprits. Your consumption seems a tad high too – do you know what’s responsible?
Good news by your knowledge of this heat pump installation.
I have a Grant Aerona installed into my new build house. In the summer it’s fine, but that more to do with the fact the system doesn’t ever have to switch the underfloor heating on because the fact the house is south facing and Mother Nature heats the house for free. So it only has to heat the hot water, which, in the warmer months, it does very successfully.
In the winter on the other hand, when the temps drop to 3degrees or below, it’s absolutely appalling. It struggles to heat the house to anything over 17degrees Celsius and hot water? Forget it.
If you live somewhere that’s 20 degrees outside all year round, great. If you live in the UK, don’t install one. They’re terrible. Having spoken to 3 other residents in the estate, all 3 houses haven’t had hot water now for 3 days. Living the dream. If I could have it ripped out and have a combo boiler installed, I’d do it in a heartbeat. The site manager is going to have a lot of cold, smelly and angry people in the site office on Monday when they return after Xmas!
Wow, sorry to hear that your ASHP has been running so poorly Alison. How hot are you able to get your hot water at this time of year? If I may ask, are your heating/electricity bills quite high?
I’m not familiar with Grant ASHPs – is there a chance they’re undersized for your property? Mind you, that wouldn’t explain its inability to heat the hot water. Getting it to 45C should not be a challenge at all.
We’ve found that 7C is the tipping point for our house and ASHP. At 2-3C we start to notice rooms getting colder. By -1C it’s more noticeable. But we’re still able to maintain most of the house at 21C.
Hi Alison, I found your comments very interesting, if a little depressing as I’d hoped that it was just my system that was faulty, and could, therefore, be fixed.
Your problems absolutely resonate with me as the minute the temperature drops, our system becomes useless – yet incredibly expensive. We have an LG pump with underfloor heating, and, like you, I long for a gas boiler or to simply be able to walk away from our “dream”, very expensive home.
I don’t want Home Farm’s website to become anti ASHP as that’s not their aim, but if you did wish to discuss this further I’m happy for them to pass on my email so we can exchange ideas and suggestions.
You have my absolute sympathy, and I feel awareness of how ineffective these systems are needs to be highlighted whilst the gov’t throws financial incentives at them.
Regards
Sam.
We have absolutely no issue with people discussing their ASHP experiences, good or bad. We have been very pleased with our ASHP, which is not perfect by any means, but it is working pretty well.
I will forward your email address to Alison shortly.
Thank you Mars, as always that is very kind of you. I understand and appreciate that you are happy to highlight ASHPs, warts and all, but simply don’t want to hijack your passion for sustainable living, as I too, am (was) passionate about living a “greener”, gentler lifestyle. But thank you for your open attitude. Sam.
You’re welcome Sam.
We’re very disappointed to hear your experience has been so bad in your dream house as a result of this ASHP. I’m guessing we may start to hear of more similar cases, and it would be great if we could figure out a way forward to get these kinds of issues resolved, because right now there doesn’t seem to be a body or organization that can help.
Maybe one of our followers can cast some insights.
Hello, I have Daikin ASHP which runs my hot water and underfloor heating. End of last year I had the unit serviced and gas changed and during the last few months the heating doesn’t heat up above 19degrees during the cold periods.
Somebody mentioned to me that If the gas was not correctly removed (mode 21) the system could have to much refrigerator gas and could be the issue why the underfloor heating is not heating sufficiently.
Has anybody heard of this as possible issue?
Hot water heats fine.
Hi Dan
The comments section on this post has grown to the point where messages and help requests have been buried. The good news is that we have built and launched a dedicated website to get these questions answered, and we would like to invite you to visit and join our new community and repost your questions there. You can do so here: http://renewableheatinghub.co.uk/forums
I am just having a Samsung unit installed but have insisted on the oil boiler being left in place. I have also asked the installer to program so the hot water is on oil and the system switches from air source to oil at 5 deg outside temp. Is 5 Deg a good balance or should that be slightly higher or slightly lower. Looking for best balance between cost of heating and having enough heat to keep the house warm. Pre Airsource we run the house at 18.5 most of the time and 19.5 in the evenings with no heat from 10pm to 5:30 am
Morning Peter. A few points:
* Heating your hot water in the winter might be more efficient, but during the late spring, summer and early autumn, you might want to consider letting your heat pump do this because there’s a lot of ambient heat around.
* The minimum temperature will be based purely on your house. Out ASHP starts to take strain at 3C when it comes to efficiency. You might want to tweak this in the winter.
* Since you’re going bivalent, you might get penalised by the RHI if your oil boiler takes on too much of the load. If you don’t have RHI, you won’t need to worry about that.
* Not knowing much about your insulation, if your heat pump has been correctly sized, you may not require your oil boiler with a target temperature of 18.5-19.C which is quite ‘cool’ – that is, however, dependant on your house.
Hope that helps.
I have just been reading comments on ASHP’s. We have had one for the last 7 years. During the winter it has been a terrible experience. First of all it favours heating the hot water so whilst doing that the central heating goes off. By the time it returns to the central heating the temperature of the house has dropped dramatically and the pump really struggles to heat the house satisfactorily. We have underfloor heating downstairs, smart rads upstairs + solar panels. The ASHP broke down three weeks ago, the manufacturer is totally disinterested. A spare part was supplied but it did not work. We have now been 3 weeks without heating and only have hot water due to the fact we installed an immersion heater last year. We are reverting to a gas boiler next week after 7 winters of misery!
Hi Jill, I have also had recent problems with a heat pump failure, which hopefully will be resolved next week, but I note your other problems concerning loss of heating when your heat pump goes into domestic hot water mode. This is normally due to the buffer tank installed on your heating circuit not being large enough, so there is not enough pre-heated water to maintain radiator temperature when in domestic hot water mode. Some of the heat pump units come with an integral buffer tank, this is rarely large enough for the demands of the average central heating system. My original installers guided me away from the integral buffer tank for this reason and my heat pump has happily coped with providing sufficient hot water, both domestic hot water and a central heating system with 13 standard radiators maintaining indoor temperatures up to 22C.
What brand heat pump have you got HMK?
That’s very disappointing to hear Jill. May I ask what the brand of the heat pump is?
Hi Alison Gray,
I was sorry to read about your problems with your ASHP.
Mars has suggested that I try to resolve some of the readers problems. Did you get yours sorted?
If not, if you can provide details of your system Model/Type etc, along with House Type/Size, I can check the specification and see whether it is undersized for your property.
I have used commercial heat pumps both in Michigan and in Washington State for over 30 years. I have been pleased with the energy savings and efficiency. I got likes from you for comments I made on three of Eddy Winko’s blog dating back to 2017. so I thought I would check your blog out. Warmest regards, Ed
Hi Ed. Appreciate the comment and for taking the time to visit our site. Eddy Winko is a few years ahead of us in his country living journey, and enjoy his blog.
Michigan gets a lot colder than us in the Welsh borders. What heat pumps did you use?
[…] to keep your sewage treatment tank healthy, to big things like installing solar PV panels and an air source heat pump to get off oil central heating and using renewables to their […]
Hello Mars,
I’ve spent a large part of today reading all your information about air source heat pumps which has been fascinating. Thank you so much for taking the time to put all this together.
I am considering using this technology for a holiday home which is based in the Lake District and rented out to guests throughout the year. We don’t’ live nearby so rely on local people to help run the cottage and sort out issues as they arise. The heating system currently uses LPG bottles and I am keen to get away from the problem of ordering and changing gas bottles. I want a system that requires as little intervention as possible!
Given that we do not live at the property, do you think the air source heat pumps are as reliable as any other heating system? I was concerned about your comments about defrosting the air pump in cold conditions. Is this done automatically or do you have to actually intervene? Can you think of anything else we should be aware of in this situation?
I’d really appreciate your thoughts
Lucy
Thanks for your comments, feedback and questions, Lucy.
In response, I can only really comment about our make of ASHP. So far, touch wood, it’s been super reliable, and the few times it did have issues, the Global Energy Team fixed the issues remotely. Their support team are available 24/7. I’m also not sure that all ASHPs have 4G connections though, and whether they are manned by support staff. This was a big consideration for us.
Don’t worry about the defrosting. This is all automated and doesn’t require manual intervention. I’d recommend that the LPG system remains so that it kicks in for a few minutes to assist with a swift defrost. This is why we left our oil boiler connected. Defrosting takes 2-3 minutes on most occasions.
Since this is a holiday home, I would automate it with as many smart thermostats and TRVs as possible, and set these to run efficiently with schedules. Guests/visitors won’t be able to change settings or heating. You will also be able to see whether everything is running as it should.
You will need a new hot cylinder for the system, and they can be quite large. That’s a notable consideration if space is tight.
I hope that helps. Let me know if you have any other questions.
Thanks Mars, got plenty to think about now.
Great. Don’t hesitate to post any more questions if you need more clarification or assistance.
Did you ever take the plunge and get an ASHP Lucy?
Hi Mars,
we have deferred the project until later this year, as there is a lot of work to do in addition to the ASHP, as we want to put in new underfloor insulation and heating too.
We want to use a local firm that can do both jobs so that limits our options. We are thinking of going with a Valliant AroTHERM ASHP. One of its selling points is the refrigerant R290 with a very low Global Warming Potential (GWP) rating of 3, that allows the water to be heated up to 75 degrees C without use of mains electricity. SCOP values 3.63 for 55 degreesC and 4.8 for 35 degreesC. However the Grant UK Aerona is also a contender with SCOP 3.72 for 55 degreesC and 5.4 for 35 degreesC.
If anyone has experience of these ASHP that would be interesting to hear.
Hey Lucy. I have also opted for the Vaillant for the same reason. I am going to install it as a hybrid with a system boiler. i dont know where you are based (i am in London) but am happy to do an introduction.
Thanks for the update Lucy. The numbers you’ve cited for the pumps are impressive.
I self built my house 3 years ago with ICF (insulated concrete formwork). Its 260m2 with double height vaulted ceilings. I installed a 5kw Mitsubishi Ecodan which copes sufficiently with the extreme cold we get here in Aberdeen. I have underfloor heating throughout and a 210ltr thermal store which has a huge plated heat exchanger to provide mains pressure hot water.
We have our Hive set at 23degrees and in the recent cold snap of -8degrees it coped sufficiently.
A few people on here seem to be missing the point. It’s not the heat pump that’s the problem. It’s how well insulated and airtight your house is!
Heat loss is everything when using an ashp. Also flow rate is critical for the performance of the pump to live up to manufacturers instructions.
It always amuses me when people slate their equipment when it’s highly unlikely it was sized for purpose.
I’m a heat pump installer and there’s a phenomenal amount of information required in a heat loss calculation before a correctly sized heat pump should be installed.
An average new build has 5 air changes per hour. Mine has 1.5. This all down to how well insulated and airtight the building is.
If you get this right from the start then it doesn’t matter which heat pump you opt for, it’ll work perfectly!
BTW Vaillant aroTherm plus is what I’d recommend.
Thank you for your professional comments and insights, which are greatly appreciated. ASHPs do work. That is not in question, and we completely agree that insulation is extremely important and cannot be understated. The one that we’ve now discovered, and that so many other consumers have too, is that the ASHP systems (especially in retrofits) have not been designed and installed correctly, and as a result hot water is not getting where it should leading accelerated heat-loss which the pump cannot satisfy. This appears to be the case for us and that’s something we’re hopefully going to get sorted out next week. Thanks again for your comments Robbie.
Well said you are wasting your time if you think you can just install a heat pump on and existing building and do nothing else, insulation insulation insulation and them airtightness and then some more you need to get your house down to the lowest heat loss possible, if you don’t you will fail
One question , can you have a hot shower/bath with ashp? Eon are installing one at my home in next few weeks. Cheers
Yes, of course you can. The ASHP will get temperature to 50C with a relative amount of efficiency. Our pump also prioritises hot water over central heating.
On a related note since you’re joining the world of ai red source heat pumps we would like to invite you to join Renewable Heating Hub where you can participate in our forum discussions and get answers to questions about renewable heating and heat pumps https://renewableheatinghub.co.uk/forums
Hi Robbie & everyone commenting.
I also live in Aberdeen, we are considering retrofitting an ASHP to the house we bought in Nov currently heated by LPG.
Robbie you mentioned it all depends on your insulation and heat moss, currently our house struggles on cold days to get to 20 degrees and when the heating goes off it plummets down through the night to about 14.
The house is 30 years old, cavity walls, 50mm underfloor insulation and will soon have 300mm loft insulation. It’s 176sqm 1.5 storey and we’ve been recommend to fit a 17hz pump. Would you say that if you have a lot of heat loss, a bigger pump will help to achieve and maintain the desired temp?
Thanks for your comments Steve. Due to the structure of comments on our blog, where replies get lost, we created a new website that facilitates better conversations on renewable heating.
We would like to invite you to join Renewable Heating Hub where you can participate in our forum discussions and get answers to questions about renewable heating and heat pumps https://renewableheatinghub.co.uk/forums
Simply register there and copy and paste your questions into a new forum discussion. You’ll get a lot more advice and feedback. Let me know if you have any questions.
We took the plunge and purchased an ASHP for our house in the UK and decided on the Mitsubishi Ecodan. We also purchased 14 solar panels and storage batteries that will store 4.8 kW of power. We did this because we had to renew our 24 year old oil boiler which was well past it’s best by date. We used around £600 of electricity and 2200 liters of oil per year (approx) which cost us, last year (2019) around £1100. Total energy cost £1700. Throughout the summer our electricity cost has been reduced by about 40% and, of course, our oil bill had been removed. The colder months have seen an increase in our electricity consumption especially when we generate very little through the panels. We found that our panels through out the summer powered all of our white goods, lighting and TV’s etc and charged our batteries but heavy consumption units like our range cooker needed the grid. The winter is looking like it will use significantly more electricity but I am reasonably hopeful that it will be far less than the old combined oil and electricity cost. I will let you know.
Thank you for taking the time to share your ASHP numbers. These are very insightful and should be helpful to users looking at an Ecodan solution. What size is your Ecodan ASHP, and to help us get an additional insight, what is is your approximate floorspace that you’re heating in your property?
The ASHP does draw a lot more power over winter (in our experience), but we find that it’s still far more effective than oil.
Out of curiosity, will you be running your ASHP heating 24/7 over the winter and have you automated your central heating in any way?
Thank you once again for sharing your data.
The noise from our LG heat pump at night (& during the day at times) means I haven’t slept properly since we bought our new eco-house. I have had the system checked and apparently there is no problem. I note that yours is situated away from the main house. Is this a problem at all as my installer insists it should not be done and decreases efficiency? Short of selling up, it may be our only option. What’s your opinion please? We have spoken before, and the situation has not improved unfortunately.
Sorry to hear that you’re still having issues Sam. I find it remarkable that your system has been given the all clear, given that it clearly doesn’t work and isn’t working the way it should. Also, your neighbour’s system is working so there’s direct point of comparison, which I find astonishing.
The all clear – was it given by the installers or did LG also send out a representative. At this stage, I think the best thing to do is exert as much public pressure on LG as possible – more on that later.
Moving the pump is an option from a noise perspective, but that won’t resolve the fact that it’s not working as it should – if I recall it’s using loads of power and not heating very well. From an efficiency perspective, setting the pump away might have a small impact, but the heat-loss pipe we used is very good and we have no issues maintaining our flow rate at 45C. To be clear, we moved our pump for aesthetic reasons. If we’d positioned it next to the house, there is no chance we’d hear it inside our kitchen or master bedroom (which would have been the two closest rooms). This is a clear indication that your pump is not working as it should and this should not drive you out of your dream home.
I would pursue the LG angle and make it their problem. The ASHP market in the UK is heating up and manufactures will be fighting for market share, so negative comments and feedback in the public domain will hurt them since they’re all fighting to wrestle away business from Mitsubishi. From my limited insights and knowledge, LG do make excellent heat pumps, so the fact that yours is very noisy and not working indicates an issue with the pump. I would contact their tech support and also see if you can find senior management that you can email.
Do you know if the pump is still under warranty?
Can you please record your ASHP and send us a short video so that we can hear the noise? You can send it to us using something wetransfer.com to contactus@myhomefarm.co.uk.
Hi Samantha Waby,
I was sorry to read about your problems with your ASHP.
Mars has suggested that I try to resolve some of the readers problems. Did you get yours sorted?
A noisy ASHP is normally a sign that there is something wrong. It could be as simple as too much or too little Refrigerant Gas, or something more serious.
Morning Derek,
Thanks for your message, it’s very kind of you to try to help people with issues.
Our Therma V pump is brand new, and during milder spells like this works with a low hum and whoosh, which is ok. However, when it’s cold (below about 3° probably) it emits a constant buzzing noise which can be heard above our TV and is too loud to be able to sleep in our bedroom – moving us into a spare.
The builder located it rather thoughtlessly on a wall in a narrow courtyard part of our garden and it faces onto a fence and I wonder if that could be the problem?
We are considering having it moved (is this possible), buying a surround, which the manufacturer claims will reduce sound by 20 decibels, or replacing it with a Mitsubishi, as the LG engineer who came and checked told us they were quieter. This final solution may sound drastic but given that over Christmas we were considering selling this house that we only purchased in September shows just how much this noise is impacting on our lives. It feels like living with tinnitus for the cold months.
Any thoughts or recommendations would be so appreciated.
Thank you, Sam.
Hi Sam,
I have only just seen your message, otherwise I would have replied earlier. You don’t have to thank me, I am happy to be able to help others whilst we all suffer lockdown. Besides you have a big plus in your favour, my Daughter’s name is Samantha.
Reading your most recent comments I suspect that your ASHP is badly sited, not only from the noise aspect but also from an efficiency point of view. It may also not be functioning correctly, but we will explore that later.
Looking at the Technical Specification for LG Therma V (though it would be useful if you could tell me which model you have) it states a noise level of 52dB(A), which is slighly higher than that quoted for an Ecodan, but within the normally acceptable range.
Rather than send loads of e-mails back and forth, since it is rather difficult fault finding via e-mail (though not impossible), I would suggest that you initially watch the following video.
MESH Energy webinar technology masterclass: Air source heat pumps.
I found it whilst I was researching ASHP with a view to getting one myself. I have no involvement with the company, so there is no conflict of interest. I would just say that the video explains in sufficient detail how ASHP should be installed and commissioned for best operation,
Watch the video and then come back to me with any questions you have on the best way to get you a good night’s sleep, without you having to wait until you are old and can just remove your hearing aid.
You are going in the right direction but you say nothing of roof insulation, draught proofing , fitting PV of the roof is a must, problem is in winter they won’t give much in the way of power, batteries is a short terms thing only last a short time, I worry about batteries in the roof space, not sure I could sleep with batteries around but there you go. Make sure your house is airtight and put has much insulation in the roof as you can get. I have 14″in the roof, cavity wall and I have been around every building joint , every time I decorate I increased the rad size to twice required, I can run my boiler in winter down to 45 and a 4 bed house on a 12kw boiler been in 10 years NOT A COMBI a system boiler and mega flow. You will fail if you don’t insulate and it will cost you a fortune. I am an energy conservation consultant by profession I am not changing to ASHP I don’t need to yet
I wonder if anyone has done a comparative study between air source heat pump and ground source pump. Would be very grateful if you can kindly share your experience.
I am planning to install ground source heat pump for my London (UK) home following refurbishment.
Thank you for your comment and questions Haresh. We looked at ground source as a potential solution for our heating, but didn’t pursue it because the installation was going to be very invasive and the costs were prohibitive. So we went down the route of an ASHP which was cheaper and much simpler to install.
As a result, I don’t have any comparative data, but I do know that GSHPs are more efficient than ASHPs. If you have the land and the funds, it will probably be the better option, and the RHI repayments are also much higher.
We built a new house in Cornwall in 2016. We are fortunate in that a small stream runs through our property, so we opted for a GSHP and a plate heat exchanger which is quite small and much cheaper than either horizontal or vertical ground arrays. The GSHP is rated at 6.5 kW, and we have a 3.5 kW solar PV system. The house is a modest 3 bed detached and with just the two of us in residence we are not thrashing our appliances. Being a new build I have no comparative data, but our annual consumption is 3916 kWh with a max monthly in January of 590 kWh and min monthly in July of 156 kWh. Generation is 3444 kWh annually with a max monthly of 484 kWh in July and monthly min of 76 kWh in January. These figures are for 2019, but very similar from 2017 to 2020. The upshot of this is that our electricity bills are around £700 pa and FIT payments approx £550, so our annual costs are £150. On top of that we are claiming our RHI payments which are approx. £1200 pa. This is paid for 7 years so we will recover approx £7k which is the material cost of the GSHP and associated parts. This was all supplied by Kensa heat pumps. Hope this is useful information.
That’s great Andrew. Thank you sharing. Some very interesting numbers and great as a comparison.
Hi not happy with air source heating. Every winter there is a problem. It cost us about 10 pound per day in winter. We find it expensive, not like they advertise. If I had a choice I would change but that would cost a lot. Sorry no pound sign on phone. Jane ????????
That’s interesting Jane. We also found the running costs last winter very high, and it’s going to be even more expensive this winter with the astronomical electricity tariffs.
Hi there electricity is about 5 times more expensive than gas, so if you can get a COP of 5;1 out of your ASHP you would be equal, however there is no ASHP capable of 5:1 COP best you will get is 2,5 to 1 over all average so ASHP is going to cost you 2 to 3 times what your gas boiler cost to run, now if you need to insulate to make the heat losses at least half of what it was before. Good luck
They are noisy and take too much space. unless you are replacing with oil and live in the country in a detached property – you cannot beat GAS
When it comes to central heating, mains gas is the most efficient way to heat a property. But it’s not the cleanest and does have a CO2 impact. I’ve read that many ASHP manufacturers are working on smaller form factor, quieter, more efficient models for urban settings, and the UK government is working on getting ASHPs integrated into new builds instead of gas boilers.
[…] https://myhomefarm.co.uk/verdict-on-air-source-heat-pumps-in-the-uk […]
Thanks for your informative & interesting video. I take it the ASHP is also providing you with DHWS for washing etc. and it would be helpful if you provided more details about your experience with it and comparisons & costs hitherto?
Thank you Brian. We’ve actually just finished recording a new video that covers many of the questions you’ve raised. I will reply here when the new video is ready and will share a link.
This has been very interesting to read thank you- we are currently looking into getting an outdoor heat pump.
We have just been told the total cost is £11k but after w government grant we only need to pay 3.5k- but I’ll still not sure if it’ll be better for us than what we have. We live in w small town in Scotland and our town doesn’t have gas at all.
We have an old economy 7 electric boiler.
I’m gonna do a bit more research before we make a decision
Thanks for the feedback Danielle. You may want to look into this, as I’m not sure it’s 100% accurate, but once you get the government grant, you’ll still be eligible for the RHI scheme so you can get even more money back. Definitely worth checking it out.
The green energy grant and rhi payments would come from the same pot of money allocated to your project, so the total amount would be the same. If you use the grant that amount would get subtracted from the total rhi you would otherwise receive. Benefit is a big lump near the start as opposed to bring spread over 7 years. We have 1 property on an ashp installed 2 years ago and it’s amazing…. Rented out currently. Our own house is having 1 fitted in a few weeks, a gen 6 Samsung 16kw monobloc. The other house is a gen 5 in a big 3 bed semi, average Elec cost is 80 quid per month
Thanks for the clarification David, and for answering this. We would have preferred the lump sum to be honest.
£80/month is excellent on the three bed semi.
After all this time through Covid we finally got an ecodan heat pump installed after 3 cancellations due to Covid. It’s only day one so in early stages. But the radiators don’t seem to want to go last 16 degrees even though it’s set at 22 ????
Very interested in your helpful blog Mars. We are looking to install ASHP. We are a flat and can install on the balcony. We are around 150m2 area overall and have 2.7m high ceilings. Any thought on output needed? We are ‘all electric’ 3 phase with a wet rad system so currently two 9 kW boilers really use a lot of juice! 7 kWh LG R32 is recommended but sounded a bit underpowered to me….
Thanks for the comment and feedback Richard. I can’t make a call on the sizing and whether it’d be underpowered, but a 7kW may be on the small side. I’d recommend, Covid-permitting, to get another 1-2 installers to quote and see what size they’d recommend.
No one has mentioned insulation? Can you – and other commenters – tell us anything about how well insulated your homes are, the type of windows, draught stopping? There’s a lot of concern about putting heat pumps into thermally “leaky” buildings. Also ground source is supposed to be better, also in terms of noise – any comments on that from anyone?
We built a new property so were able to design a well insulated thermally efficient house. We have 100mm foil backed PU insulation layer in the floor with underfloor heating in a 60mm screed on top, the internal structure is timber frame with 125mm foil backed PU insulation in the walls and roof. We have high efficiency double glazed windows and doors. We have a Kensa ground source heat pump, which is quite noisy, but no more than the oil fired boiler at our previous house and as we designed the house we created a separate small room to house the boiler UFH pumps, manifolds and all electrical and IT equipment. Being in a separate room, the noise is no more than that from our fridge/freezer in the kitchen
We spend a lot of time insulating our period property. We have double glazed windows and foil backed insulation in our walls, and whenever we come across a draft, we address this to prevent heat loss. Our property is by no means perfect when it comes to being insulated, but the ASHP still manages quite well. The better we insulate, the more we’ll increase our efficiency.
Before we had our heat pump installed we happy and the anual bill for gas was about £2000-£3000 , since getting rid of LPG and haveing all the house run on electric our electric bill is £1320 we also run two big American washer and drier. We do have solar panels and get money back each reading but obviously depending on weather it is different each time . We also live in the far North of Scotland , wet windy cold hot. Three seasons in one day.
So far we have been very happy with the heating unit apart from the control panel, it goes crazy every time we have a power cut . But we were told that it is an old model.
With us both being disabled we tend to have the heating on 24/7.
So in conclusion I personally think that it is a great unit . We have a double fan unit and it heats a large 4 bedroom 2 reception detached bungalow.
That’s brilliant Ralph. Thanks for sharing, and it’s great to hear that your ASHP is getting the job done in the north of Scotland.
they are noisy – unsightly – and expensive – neighbours complained about fan noise and heat exchanger fan
GAS IS THE BEST IF YOU ARE ON THE GRID – had to have additional heating on in the water and electric boost for the hot water
could not wait to get rid of it
never again
Sorry to hear about your ASHP experience. Can I ask what pump you had?
Hello. I’m thinking of replacing our conventional gas boiler (CH & HW) with one, or two, air source heat pump(s). i.e either one to do both jobs or one to do the CH and a smaller independent (internal?) one for the HW. We have a 5-bed detached house with hot water tank and radiators. Double glazing and insulation are OK but may need improving. We’re on mains gas but obviously that’s a limited resource and prices are only going to increase, our boiler will need replacing soon so I’m thinking ahead about a renewable alternative.
A couple of initial queries you may be able to help with:
– the size (power) of unit required. Our gas boiler is rated at 18kW but some websites indicate a 4 bed house needs just an 8kW unit.
– whether the heat pump can be a straight swap for our boiler, or whether a new cylinder is also needed. Some manufacturers imply that the cylinder must be replaced, but in other places they say it can be a straight swap. Your write-up seems not to mention the cylinder.
– running noise. The main components are a big fan and a compressor. Although we are in an urban neighbourhood we want to keep the noise levels down. Your house seems fairly rural, do you have a sound recording of the unit runnung?
Thanks, Ian.
Thank you for the comments and questions Ian.
Pertaining to the noise, I don’t think it’s as invasive as people make out, but it’ll vary from pump to pump. Each situation and placement will also impact the sound. At around the 16:00 of this video you’ll get an idea of the fan noise: https://youtu.be/P8cBKBTTLBw
As far as the cylinder is concerned, yes, you’ll need a new one. We speak about our full installation experience here, and discuss the new hot water cylinder: https://youtu.be/c3V0k_GeFOo
I hope that helps.
Have recently had a ashy installed to replace an old gas boiler. Although it heats the house up well am worried about the running costs. Listening to your video would it be better to keep the temperature constant all day. Have a Nest thermostat and use this to control the temperature. At moment I have the heating set to 15.5 at night and 18 during the day but wonder if it would be better set at constant 18.
Thank you for your feedback Desiree.
We’re now in our second winter, and heating costs are always a consideration. Your 2.5C gap between economy and comfort temperatures is quite large. We’ve noticed that bridging 2.5-3C takes a long time and draws a lot of energy.
For us, it’s been a lot of trial and error. Run your system the way you have for two days and note how much electricity you’ve used to drive your heating. Then adjust to 18C 24/7 for two days and note down the electricity usage. Then compare. Also, if possible, make a note of outdoor ambient temperatures as they may skew figures. At the moment it’s consistently cold, so could be a good time to experiment. Your heat pump, like ours, may give you all this data.
Then see what’s best for you, and your house.
Please us know what the outcome is.
We live in a detached house of about 100sq Mtrs. Correctly our newish economy 7 storage radiators plus hot water costs about £1600 a year. Would an ashp save me money?
Thanks for the question. Do you have a wet central heating system in place? ASHPs will probably be more efficient than storage radiators.
Hi, we currently have a gas warm air central heating system in our 5 bed house and given we are considering replacing the majority of the floor downstairs and likely with underfloor heating, we want to look at ashp. Possibly alongside pv solar panels. Current heating just has a dual which has to be turned to alter heat levels which means it’s hard to control temperature. Is ashp likely to save us money? As well as green incentive.
We are detached but very close to neighbours, is the noise likely to cause us all issues?
Thanks
Thanks for the comment Rosie.
ASHPs will not outperform mains gas systems, but they are greener and better for the environment.
The green incentive payments are very helpful but will not cover the full cost of most ASHP installations. We get RHI payments and they are very helpful.
Would definitely recommend solar PV, if you have a favorable site for them.
Noise will vary from pump to pump. We don’t find ours that noisy, but there are some models that are quite noticeable and annoying. Most pumps publish their noise levels, so it’s worth studying those.
Hope that answers your questions.
Thank you, that’s what I’ve been reading. We plan to be in the house at least 30 years, so whilst we are replacing the floor, feel like we should consider underfloor heating and therefore ashp, especially considering the future of gas. But don’t want to do this at increased ongoing financial cost.
How would we estimate the potential annual cost?
Hi Rosie,
Apologies to Home Farm who I know are great supporters of heat pumps;however, I would personally ask you to think extremely carefully before proceeding.
We purchased a £700,000 eco house in September which has underfloor heating powered by a pump. 3 months later we will we could sell up and walk away. The noise from the pump is horrendous and can be heard over the tv, and I haven’t been able to sleep without earplugs or tablets – and even then am disturbed by the noise.
The house is never warm. We have given up on heating 4 bedrooms and struggle to get others above 17 degrees.
And all this for bills of nearly £300/ month. I accept this is simply our experience, but as I dearly wish I’d never bought a property with this technology, I wish someone had shared these possible issues with me.
Good luck,
Sam
Sam raises valid concerns about ASHPs. If they’ve not been correctly installed and commissioned they can run very poorly and inefficiently, as appears to the case in Sam’s eco property. We had a slight issue with our ASHP just before the new year (we’ll post a video about this in a week’s time) and it can become stressful because heating in the UK is so important over the winter. Having said that, this would apply to any other form of heating too, where the oil boiler we inherited was also not commissioned or set up properly.
From our experience, when committing to an ASHP there are two major factors that have to be considered:
1. The brand and size of the ASHP matter.
2. Selecting a competent, professional installer.
When we were getting quotes for ASHPs, half of the installers that came across were cowboys and didn’t instil us with any sense of confidence. Many were central heating installers that decided that there was money to be made installing ASHPs. After months of deliberation and weighing things up, we opted for Global Energy Systems’ ASHP (the 18kW model) and went with the installers they recommended, which they had vetted on our behalf: All Seasons.
The GES pump is excellent (but does require monitoring and tweaking from time to time, as will the case with most retrofit projects) but the All Seasons installation team were professional and competent, and who had experience installing ASHPs. For us, it all hinges on the installation team (which was also the case with our solar PV system we installed), because you can have the best equipment in the world, but if it’s installed incorrectly or not set up for a property’s requirements, it won’t work as it should, which is sadly what I think is the issue with Sam’s ASHP.
Morning Rosie.
We’ve just shared our December monthly costs in this post: https://myhomefarm.co.uk/air-source-heat-pump-performance-for-2020
This is the heaviest month we’ve had in terms of running costs, because of the cold, wet, humid weather. I hope that helps.
Thanks. Other than the unit, what physical alterations are needed to heat a property by ashp?
I am assuming underfloor heating is a wet system so would be costly to dig up the floor to install?
We have a warm air heating unit but no ducting. And the ashp would probably need to be on the rear of the property and I’m worried the front of the house would be cold?
Thanks
I’m not au fait with warm air systems, but ASHPs should be able drive a radiator only central heating system. Our upstairs rooms are rads only, and we maintain them at 21C.
While UFH works well with ASHPs, the right size pump with rads is also effective.
Rosie, do you have good all round insulation to the rooms being considered for u/floor heating? If so, have you considered DIY elecric heating e.g. Warmup?
New user of ASHP
Congratulations Sue. What ASHP did you install and what has your experience been like so far?
It was installed by our developer in 4 new homes on Welsh border. A Grant system.
How long have you been running the system and is it keeping you warm this winter?
Hi Mars
Only about 5 weeks since we moved in. We have sophisticated digital room sensors in each ground floor room underfloor heating and rads on first floor. There are week and weekend settings and one on first floor setting the temp for all bedrooms. Most are set at 20.5 with bedrooms at 19, nd the house remains warm 24/7.
We have used 1100 kws in about 30 days incl appliances etc.
I will be applying for the Renewable energy incentive scheme.
Will be interesting to see the net cost over 12 months. We have moved from the sunny south coast with south facing gardens to a wetter climate and rural setting but well worth it for the peace/hills around us and views to die for!
Sue
Sounds like you’ve got a good setup that’s working well, and it also sounds like you’ve moved to a beautiful part of the world. Great to hear.
Definitely apply for the RHI because the repayments are very good. Please keep us posted on the performance and effectiveness of your ASHP.
Been looking at ASHP for our cottage and very pleased I found this site, while not decided on a brand I’ve found installers have their favourites, I would be keen to hear of noise levels for Nibe and Valiant if anyone’s got experience of them
Thanks for the comments and feedback David. It’ll be interesting to hear if anyone has used Nibe or Valiant. You should also give Global Energy Systems a ring (the manufacturer’s of our pump) because they have some very good pumps and their customer service and support has been excellent.
Thanks for putting the video together Mars. Very informative and interesting.
We also live in a converted farmhouse (Yorkshire) and have no mains gas, so our primary heat source for central heating and hot water is oil. The boiler is now close to 30 years old and I am sure it won’t be long before it fails beyond economic repair. We only rum the boiler through the winter and only in the evenings. It’s a five bedroomed property with around 240sq M floorspace. We only have radiators, so no underfloor heating. Through the summer and in the winter we also run an immersion heater on Economy 7 to provide, or boost the hot water.
I am in discussion with an ASHP installer about converting our system, including upgrading the radiators and installing a new heat store tank.
Would you mind telling me roughly what your floorspace is and what was the output of your old oil boiler that the 16kW ASHP replaced. How many rooms are there in your farmhouse?
We like the idea of 24/7 background heat and if we went with a well set up ASHP we would be able to eliminate the estimated £500 per annum immersion heater cost , as well as the 2400 litres of oil we use.
Do you know how many kW your ASHP has used over the period of a full year.
It would be great if I could get an idea of how your property compares to ours and how much electricity you have used to drive the ASHP. Whilst I understand the theory and the sales pitch being given to me by the installer, it would make sense to sense check their projections against a similar property. They are proposing a 17kW unit.
Thanks in advance for any insight.
Thanks for the feedback, comments and questions TD.
We’re heating around 4,000 sqft (370sqm), which consists of our large downstairs living area, entrance hallway, five beds, TV room and annex.
I’ve just posted our 2020 ASHP consumption which will give you a good idea of running costs: https://myhomefarm.co.uk/air-source-heat-pump-performance-for-2020
The key to saving is to get the lowest possible electricity tariff: as close to 10p/kWh.
A 17kW sounds like a good size for your property because our 18kW handles our requirements. May I ask what brand up your installer is proposing?
What’s your general insulation like, because that’ll dictate your pump’s efficiency.
Thanks for the quick reply Mars.
Unfortunately the installers have come back to me this afternoon and told me that it doesn’t look cost effective. Mainly due to the location, layout and age of the property.
Their calculations indicate that we would need 2 x 12kW ASHP units to guarantee sufficient output. And we would need a 3 phase electricity supply to handle the start up surge current requirements of both units (even though the units are DC inverter based). They were proposing units manufactured by Grant.
They did suggest that a hybrid type system could be an option, utilising a smaller oil boiler to supplement the ASHP, but they recognised that again this wasn’t a cost effective solution, due to the initial capital cost.
I may get a second opinion. But as they were so thorough in their evaluation and honest enough to advise against it, I am not sure that a second opinion will tell me a great deal more.
I’m going to update the boiler controls so we can trial running the boiler for longer periods, but with a lower room temperature setting overnight. Doing this should eliminate the need for the immersion heater. Also, I will balance all the radiator flows and adjust the circulation pump speed so I can optimise the delta between the flow and return temperatures.
Then I’ll start investigating more efficient oil boilers, as sooner or later our old one is going to pack up completely and be too expensive to repair.
Never a dull moment!!
Thanks again for your reply
Thanks for the update TD. From what you’ve said, it seems they are a credible company and aren’t trying to push the sale. That’s heartening.
On the back of that comment, I’d definitely recommend a second opinion. We did have one company proper to us we needed two Ecodans, which wasn’t the case at all.
I’d recommend All Seasons, who are based in Sheffield, and they’re the guys that installed our system. I think they cover all brands of ASHPs, but focus on Mitsubishi. They were a professional, experienced outfit: https://www.allseasonsinteriors.co.uk/contact-us/
Running the boiler for longer at lower temperatures seems like a good idea.
As for balancing, we’re still having horrible issues with two rooms (one of which is the TV room) which I need to get on top of. Just not enough hot water getting through.
Like you said, there’s never a dull moment with central heating system.
Second installer has looked at the house and they have also concluded that we would need 26KW ASHP and most of the radiators changing for it to work satisfactorily.
So now working on plan B which is a more efficient condensing oil boiler which we will locate externally to reduce noise and free up space in the kitchen. Awaiting two quotations. Part of the work will involve converting the hot water and central heating circuits to valved control which I am told helps efficiency as well. I have also installed a Hive control system myself which is giving us better control over the times and temperatures for the central heating.
Since we are now running the boiler more often I have been able to switch off the electrical immersion heater which ran on Economy 7 overnight with a 2 hour boost around tea time.
We don’t have a smart meter, but I have been monitoring the E7 consumption for close to a month now and it has dropped by an average 4.5KwH per night over the past 30 days. I’m not sure exactly how much we have saved by not running the immersion heater through the day, but we have also not needed to put on any electric heaters during the day. Looking at the average daily consumption from historic bills for winter last year, compared to the last 30 days, I think we are saving around 4.6KwH on the day rate as well. On our current tariff from E.ON the combined day and night savings equate to circa £335 a year.
It’s early days and I don’t yet know how much extra oil we are putting through the old boiler, but the £335 electricity saving will buy us close to 850 litres of oil to offset against the extra boiler use.
Hoping that a new condensing boiler with a claimed efficiency of +/- 94% and a more efficient valved flow control system will help to reduce our oil consumption significantly compared to the old boiler which has a published efficiency of 70%. (and that assumes it is running as well as possible!!)
At 94% efficiency I think it should also be more economical to heat the hot water only through the summer than using Economy 7. If I’ve got my maths correct. then our current Eco7 cost per unit is £0.066 (and likely to increase when the current contract expires in April). 1 litre of kerosene is £0.35 which works out at around £0.037 per unit at a 94% efficiency.
I guess time will tell !!
TD, I’m looking for a reputable ASHP Installer in Yorkshire, would you mind saying which companies advised you on your system?
I have been reading your comments about lowest tariffs for electricity. We can’t seem to find anything much under 17p per kw. and 20p per day standing charge.Even getting a supplier to respond in offering a contract is proving difficult in this climate. We have been in our new build home since 30 Nov and still waiting for a welcome pack.
For the past few years we’ve managed to get rates around 14p/kWh, with standing days rates that were over 20p. This is the first year we stalled and couldn’t find anything less than 16p/kWh (that was with GOTO Energy), until George suggested Symbio to us which was just under 11p/kWh with a standing rate of 20p. Every year, when I look for new suppliers, I’m astonished at how many providers (large and small) have tariffs around or over 25p/kWh. Crazy.
And as you’ve pointed out, the current Covid situation is just going to make it more challenging.
My wife recommends Flipper whom she has used for years for a house she managed. For a small annual fee they will monitor electricity prices and will suggest that you switch to keep in the best available deal. They ask you if you would like to switch then do it for you if you say yes. She swears by them.
Thank you Iain. I’m going to check them out right now.
Signed up with them today. Let’s see if they can find a cheaper provider.
Very useful site – thank you. We live in a 2700sqft 20 year old bungalow. We have triple glazed, doubled the loft insulation to 300mm, blocked up drafts, a new A Rated oil boiler 6 years ago, 4kW of Solar PV and an electric diverter that uses spare electric to heat hot water. An electric car too 🙂 We currently use about 1200-1500L of oil per year and about £45 of electric / month. Our home has an EPC rating of B and energy demand of 20,000kWh.
I continue to be keen to drive down our CO2 output, so was investigating an ASHP solution. Mrs C has said “NO” to underfloor heating or radiator enlargement (note: we already have quite a lot and large radiators).
I have been investigating an Hybrid ASHP system – an 8kW Samsung unit would be added to our existing oil boiler to cover “80%” of our heating needs, the remaining 20% the oil boiler would kick in. It would be funded through RHI – they system would be cost neutral, only having to pay for electricity.
So my questions would be: your thoughts on an Hybrid System? I note you kept your old boiler – how often does it kick in? Where did you find an energy supplier at 10p/kWh? I pay 14.5p and 5p for 4hrs at night to charge the EV. Any advice or wisdom gratefully received
Thanks for the comment and questions Julian. Your house and set up sound great. Love the drive towards lower CO2 footprint.
On the subject of UFH and larger rads, those are requirements for houses that lack insulation and that lose a lot of heat. That’ll be something an installer can evaluate at a site visit.
I have some “issues” with bivalent systems. Ours included. The ASHP will run 99.9% of the time and get small boosts from the oil boiler, as is the case for us. The issues occur when we need to switch over fully to our oil boiler. I’ll be tackling that in our next video. Not sure how you’d get an 80/20 split, and what implications that has for RHI repayments, because the RHI want a higher percentage of ASHP usage.
As an initial thought, the 8kW Samsung might be a tad small for your footprint, but that’ll be something that’s addressed at your site visit as it sounds like your insulation is excellent. It’ll be interesting to see what your heat loss calculations come back at.
Our boiler kicks in on most days for a total of 1-2 minutes. Minimal.
Energy at 10p/kWh: George, who posts and comments on our site, recommended Symbio Energy who have recently switched to. Our previous rates were 15-16.5p. So far Symbio have been great.
I’d definitely get an installer or two out and see what they say. Would be happy to share my thoughts on their proposals.
Evening Mars. Thanks for the continued ASHP discussion on this site. I think I’m moving away from the idea of an hybrid system, keeping our oil boiler & adding an 8kW ASHP. Instead I’m pursuing the idea of a Daikin Altherma 3H HT 16kW system. HT = high temperature. It’s also super quiet. Calcs show an electric demand of 7300kWh to deliver the 20000kW of heat. Daikin has a 10 year fixed price service package which I like. But their monitoring and links to agile tariffs is missing. I’m also looking at the mixergy hot water tank.
Hi Mars,
Thank you for sharing your data and experiences, all very interesting. Currently planning a new build in the North of Scotland and hoping to install a 7kW Panasonic ASHP. House is a single storey, 110m2 with wet under floor heating throughout. The ASHP must also provide hot water (2 sinks and a shower) for 2 adults, and a heated towel rail in the bathroom. We have had guidance on selecting the heat pump and tanks, and we are happy with the size. The house will be very well insulated with triple glazing, although not quite passivhaus standard. We were advised around 3kW to heat the home. We therefore hope that the ASHP will rarely need to be running at 7kW, and mostly be using much less power.
I just wanted to ask, from your experience, how does the ASHP usage vary over the day – how often does your system draw the full 18.8kW?
Thank you for your comments and feedback LJA. It sounds like your new house in Scotland will be well insulated and the ASHP should work well.
In response to your question, there’s something very misleading about the ‘sizing’ names for ASHPs. I recently asked an ASHP engineer about this, and he had no answer for me. He couldn’t answer my question as to why our ASHP is 18kW in name. To clarify this point further, the 18kW system we have, never draws 18kW of power – doesn’t even come close. Our system, at peak, draws between 3-4kWh of electricity, which is why on very cold and wet days (with frequent defrost sessions) we consume about 80kWh of electricity over 24 hours (about 3.5kW per hour).
Your heat pump, despite the figure that’s been quoted in the model number, based on the insulation and size of your property, will probably never peak over 3kWh.
This is something that I’ve wanted an answer to for quite some time, and I’ll do some research this week, and hopefully update this comment with additional clarity.
Regarding the ratings of heat pumps, what is classed as an 18 kW heat pump has a maximum ‘theoretical’ output of 18 kW of heat. Obviously in optimum conditions, and due to the COP, the input energy will be much lower. We have a groundsource heat pump rated at 6.5kW, and the compressor motor which is the majority of the load is a 2.2kW, drawing approximately 1.5 kW in operation.
Thank you Andrew. That makes sense. Thanks for the clarification.
Thank you both 🙂
That’s really helped to clear that up for me!
Links to note on 8th Jan. Thank you. I have since been talking to a different ASHP supplier / installer. Having done the demand and loss calcs he is proposing removing the oil boiler completely and installing a 16kW Daikin HT system and a new h/w tank. Higher price (but only by £3k) but I like the idea of no oil. Also no radiator changes which my wife very much prefers. Keep up the information and good work. I am only upset by how tidy your place is compared to mine 🙂
That’s brilliant Julian. Sounds excellent. Please keep us updated on your progress and definitely let us know when the pump is installed. Good luck!
Hi,
I am in the process of designing a new house approximately 300m2.
My preference is to install a ground source heat pump with a surface array but unfortunately I don’t have sufficient adjacent land available and vertical bore holes are looking prohibitively expensive.
Does anyone know if it is possible to combine an air source heat system with a ground source system to provide the warm supply water to the compression heating system. ?
I hope this question makes sense to someone.
Thanks Paul C.
Thank you for your comments John. I’m limited in my technical knowledge and know very little from a practical perspective about GSHPs.
There are some knowledgeable people that follow us here and on the YouTube channel, so maybe they’ll be able to cast some insights.
Can I suggest that you also post your question here too: https://youtu.be/XaZ2CmXUp-g
Hi Paul,
We have a GSHP, and despite not having sufficient land for a ground array were fortunate to have a small stream which we abstract from to provide our heat source. I am struggling to understand why you would consider combining an ASHP and GSHP. Both can provide the source of heat for underfloor / wet systems, unless you mean to have both systems with the ASHP assisting the GSHP due to limited ground array?
Hi Andrew,
Yes, you have the gist of my question.
Is it feasible and realistic to combine an undersized ground array with an air source system ?
Very keen to hear the answer to this.
Having worked in process engineering for many years, there is, in theory no reason why you cannot use both a GSHP and ASHP on the same heating system. The issue will be finding a supplier to design and commission a suitable control system. In essence, you have a warm water heating circuit on which your building is imposing a heat load or demand. This requires a heat input to maintain a temperature set-point. A control system with temperature transmitters on both the heat source inlet and outlet connections will determine if the boiler is increasing the circuit temperature at a pre-determined rate. If the programmed conditions are not satisfied, i.e. inadequate heat input, then it will demand a second heat source to assist. This will be the case for commercial properties with boilers, but my experience in this sector is very limited. To a control system designer would be a simple process but really you need to find a standard heating control system on the market, as bespoke control systems will most likely be prohibitively expensive. I will do a bit of research, and post a comment.
This article is worth a read on cascade boiler control systems. More for commercial systems, but the principle is commonly used.
https://modbs.co.uk/news/archivestory.php/aid/12710/Cascading_control__.html
Here we are. This is an off-the-shelf solution, but the system design will need careful consideration. It will need a heating engineer rather than a plumber!
https://www.vaillant.co.uk/commercial/products/vrc-630-boiler-management-control-37568.html
Another option from Grant.
https://www.grantuk.com/products/accessories/grant-ges264-sequence-controller/
We recently installed a Panasonic 7.1kw ashp ( split unit) in a log cabin at the bottom of our garden. Very quiet and mostly warms the 48sqm cabin ok. As it mainly a garden office , it isnt well insulated, roof and floor insulation plus d/g, but only single skin 70mm thick logs. It is wifi controlled etc and alexa compatible. Too early to feedback running cost data. Issue we have is the unit sometimes shuts down before reaching temperature . The power light starts to blink and the vanes close up. Anyone got any ideas what might be the reason, before I get the installer back and potentially get the runaround. Thanks.
Maybe answering my own question. The external unit is going into defrost mode which apparently can last 30 minutes. We are seeing a noticeable drop in temp during that time. We have been recommended to leave in Heat mode rather than Auto and to set the temp to a couple of degrees above desired temp to allow for the 30 min “ no heat” temp drop. We will test to see if this holds true but may be helpful for anyone thinking of heating/ cooling their conservatory etc. Steve
Hi, We have an LG 12kw, HM121M U33 ASHP in a new 4 bed, 2500sq/ft house, underfloor heating on ground floor and radiators upstairs, it also provides the hot water. I work overseas a lot so there is only one person living there and underfloor heating is set to 21degrees. For the last few months it has been costing around £300 a month on Octopus tariffs , 14.6p kw/hr I think. The downside is the house although very well insulated does not feel very warm and the floor slab not toasty underfoot and my wife is scared to turn it up higher due to cost. We moved from a lager house last year which used oil central heating, also underfloor, and it felt warmer and was much cheaper to run although less well insulated. Really disappointed so far, are we doing something wrong.
There appear to be issues with LG ASHPs. Not good, and not the first report of these pumps just not getting the job done.
Hi Douglas
Like you I also have an LG pump , in a similar size property, with which I am hugely dissatisfied. Furthermore, May I ask you if yours emits a horribly irritating buzzing sound when it’s running? This is now the soundtrack to our life in this house to the extent we have to have the tv up loudly to drown it out, and are unable to sleep in our master bedroom, having instead to move into a spare room – hopefully only until the warmer spring. At the point of investigating if it’s possible to change system to lovely cheap, quiet gas. Sorry environment, but my standard of life is also important. Be interested to hear if also an issue for you?
Completely understand your frustrations Sam. It’s ridiculous how noisy your pump is and that it’s not heating the house, and not surprised you’re considering shifting to gas.
Sam, I don’t think it makes much noise but can’t be sure, I’ve only spent 19 days there since we moved in last July! I think my wife would have mentioned it if it was but it is behind the garage and not really close to any living areas tbh. I’m with you on the gas though, unfortunately there are only 4 houses and the builder did not bring gas in to them so now not possible really. My wife sent me all the bills last night and I think over the year it should end up being around £2000 (£160 a month) to run the system which is not as bad as the current £300 a month seems. She spoke to next door last night and they’ve just had a £400 bill so feeling lucky now ????
Hi There! this website has been so hard to find but am glad you set it up! Long post alert as i am really stuck!
Am in the middle of a refurb/rebuild of a 1930’s semi in London. It will be 300sqm over 3 floors when finished with a 50sqm annexe. I am looking at ASHP, MVHR as well a VRV system and solar PV/thermal. (I have also thought of installing a gas boiler as a backup system for when its really cold)
Windows are triple glazed or double with blinds with u values in the 1.4 region and the rear of the property faces west. Heating in the house will be under floor to ground floor and radiators everywhere else. i have been recommended a NIBE 16kw unit by two installers. my concern is that the NIBE unit i am told experiences performance issues in low temperatures.
i tried (miserably) to carry out research and know the LG has a really bad cloud platform. I have been told about a new Vaillant arotherm unit by another installer which uses r29 refrigerant. does anyone have knowledge of NIBE or Valliant or another.
I am also worried about noise levels and the struggle to heat in lower temperatures as my father feels the cold the most
Thanks or reading and I would appreciate comments good (or bad!)
Pavan
Hi Pavan, avoid the LG as it has a horribly noisy buzz when working hard, and if I had any choice in the matter (it was already installed in my new build) I would chose gas for the economic, quick and easy warmth it allows. Out of interest, what is a bad cloud platform that you refer to regarding the LG?
The cloud system probably means that the data generated by the pump goes online where you can access it, or you can control the pump remotely via your internet connected devices like phones and tablets.
This is a feature, in my opinion, that is really lacking in ASHPs (ours included), especially at a time when our homes become ‘smart’.
Hi, I’m after people’s thoughts and advice. We currently live in a 3 bed semi in a rural area of Merseyside. House has solid walls ( no cavity insulation) roof was replaced a few years ago and the loft space is well insulated, but there are draughts nearsome windows and vents. We are currently on coal heating (no mains gas available) so we have to light a fire heating the back boiler for about an hour before we can put the radiators on. Also we do tend to get power cuts maybe twice a year sometimes. The housing association who own the house are wanting to remove the current system and replace it with the air source supply heating! We always stock up on coal 7 months of the year which at the current cost is about £1270 ( price is currently £23 per bag @ 8 bags per month for 7 months a year. We don’t buy it in summer months and we use the coal essentially between October and March depending on temperature/weather). The question is will the air source heating be cheaper and more cost effective or would people stay on coal
Thanks for the question James. This is a tricky one to answer. NMay I suggest that you create a free account on our sister site and copy and paste your question there, which is likely to get you a better response: https://renewableheatinghub.co.uk/forums
If the replacement system is heat pump, I don’t think it will heat up to 22 c because of low insulation and the poorly fitted windows you have
i head the same about decibel levels. am going to be acoustically insulating bedrooms to avoid this
Thanks for the post Pavan, and your refurb sounds very exciting. I don’t know much about the Nibe or Valiant. Have you not considered an Ecodan, which is probably the most popular ASHP in the UK?
Most ASHPs should not struggle with UK low temperatures if they’ve been sized correctly for your property and have been commissioned properly. From what you’ve described, you should be more than fine maintaining temperatures at 21C+ with the right pump.
Also, when speaking to installers, ask them about the physical size of the pumps and how much space they need around them. That’s important. Don’t box them in.
And make sure your get a hot water cylinder with a buffer store.
To get more answers to your model questions, I’d suggest you post your question on our YouTube channel where there’s more diversity when it comes to ASHP users: https://youtu.be/XaZ2CmXUp-g