Air source heat pump questions and answers

by Mars

We have received hundreds of comments and questions regarding air source heat pumps from our YouTube channel and blog followers. We have answered most of the questions in writing, but we thought it was a good idea to collect the most common and relevant questions and answer them in this video.

The feedback we have received to our air source heat pump videos has been amazing, and we’d like to take this opportunity to thank everyone for their support and for watching. It’s greatly appreciated.

These are the full questions we’ve answered in the video.

Question 1

Which is best way forward: Green Home Grant (GRG) or Renewable Heat Incentive (RHI)? Nigel

Question 2

Look forward to finding out about the maintenance costs in your future videos as such info is more available for e.g. gas boilers, but wondering about the long term maintenance costs of ASHP. Flickafy

I assume these systems need a regular service check. Is it expensive? Endo

Question 3

Thanks for this set of videos. You touched upon your bills but you didn’t mention how much your electricity bill had raised post-installation of you ASHP (I understand all the provisos/solar panels, etc.) but would be interested to know. Thanks. Guy

Question 4

When you say that you keep your pump on all the time does that mean you keep it at 21C, 24 hours a day? I’ve been turning ours down to 19.5 when I go to bed. Can you just verify this? I’m thinking of the financial and efficiency side. We do not have underfloor heating just radiators. and we have solar panels too. Andrea

Question 5

In terms of water usage, can you run hot water continuously or will you run out of hot water quite fast? Sebastian

Question 6

How do you calculate the COP? I’m surprised that the house insulation is a factor in it. Wout

Question 7

When standing next to the heat pump outside how noisy is it? Rowan

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anna mycoe
anna mycoe
1 year ago

Hi Mars
In relation to Q1. Something you mentioned didn’t ring true so I’ve had a read up and you do not need to inform the The dno approval is not needed in advance of installation. The dno is notified post installation with what is called “fit and inform” rules. It is noted on the mcs certificate.
The DNO respond, eventually, at their leisure. But just like with solar pv it can take them many week, if at all.
The dno notification is not needed for the RHI claim.
Hope this helps
Anna

Mark Crooks
Mark Crooks
1 year ago

My experience was the same as Anna’s. All I needed for the RHI registration was the EPC and MCS certificates which contain info required for the registration forms.

Mark+Crooks
Mark+Crooks
1 year ago

On the subject of electricity tariffs, do you have any data on when the ASHP uses power? i.e. time during the day. Particularly over winter.

I’ve just read up on Economy 7 and Economy 10 and wondered if those might be beneficial for ASHP systems.

Name
Reply to  Mars
1 year ago

Well….you use yours during the day from the solar and during the night for economy whatever. Win-Win.

Andrew+Scott
Andrew+Scott
1 year ago

I have read a number of posts regarding a disappointing ASHP experience. This concerns me as it is likely that in the next few years, new oil and gas boilers may be phased out, certainly in new builds, so we will all be increasingly relying on electricity as our main source of heat for homes. Obviously the more electricity we can generate from solar and wind is key, but for central heating and DHW, heat pumps are the most economical technology for converting electrical energy into thermal energy whether ASHP or GSHP. A heat pump should have a COP of at least 3, in our climate, and should be nearer 4, so the technology is not a problem. This leads me to question what else can be at fault? If it is noise, then it may be that the heat pump in question has a manufacturing or design issue, or perhaps it is not installed in a suitable location. These things should not arise with a good heat pump and installation design. The main concern that I have is that if we are selecting heat pumps as a low energy heat source, then we need to ensure that the property is suitably insulated. With a new property built to current building regulations, it should be a given, but more of a challenge for older traditionally constructed properties. We built a new 160m2 house, of timber frame construction, suspended concrete beam and block ground floor, and with the floor, walls and roof insulated, our total energy averages £60 / month. Our solar PV obviously contributes a small amount, but more significantly the FIT payments are averaged at £50 / month, so our energy costs are just £120 / annum. If heated our house with direct electrical appliances, then I would not expect to pay more than about 3 times this, i.e. £360 / annum. To conclude I can only surmise that the poor performance is down to a badly designed system, or a poorly insulated building. In support of this, I also have a close friend who has a bungalow with an ASHP and UFH and also my nephew has a small bungalow with the same, and they are both warm, and pleased with their energy costs and systems, so I think the focus should be on the building and the heat pump contractor rather than the technology itself.

Andrew+Scott
Andrew+Scott
1 year ago

Both examples of ASHPs I have experience of have the compressor mounted on heavy rubber blocks which in turn are mounted on an independent concrete plinth. If there are installers out there mounting them on a building wall using metal brackets, I am not surprised there are noise issues. In my examples, the only thing that you can hear indoors is the circulation pump, which is no different to any other traditional central heating system. The only other aspect would be ensuring no vibration is transmitted via the refrigerant pipes, which must have suitable insulation and flexibility in their connections. This is all about good installation practice. Noise should not be an issue or require additional accoustic enclosures to resolve in my opinion.

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