I’ve received a number of questions about how much our central heating system upgrade set us back, so this post discusses how much our air source heat pump cost.
Before we get into specifics, we need to put our pump installation into context. Not every air source heat pump (ASHP) installation will cost the same because each and every installation is different and home requirements will differ. For starters, we needed an 18kW unit because we had over 4,000sqft to heat.
In addition to this, we didn’t want to have it located right next to the house (because of the humming noise it makes) so we placed it 25 metres away from the main building. This had a significant cost implication because we needed to run an expensive heat-loss pipe from the pump to the house.
We also had to replace our old water heater and replace it with a unit that could work with the air source heat pump. This is a cost most households will have to incur when moving away from oil or gas boilers to ASHPs. Thankfully, we didn’t have to modify any of the pipework, and we kept all the radiators.
Air source heat pump cost breakdown
|300DHW and 100L buffer store||£1,500|
|Commissioning and MCS||£500|
|VAT @ 5%||£763|
From the table above you can see our air source heat pump cost just £16,000. Had we placed the ASHP next to the house, we could have saved £780.
About our system
We opted for the 18kW Caernarfon air source heat pump as it is built in accordance with guidelines set out by the Microgeneration Certification Scheme (MCS). The scheme specifies that the system must be capable of providing sufficient heating for our property down to our local area’s design temperature which, for us, is -3.3°C. In other words, the design temperature is calculated as the temperature that is exceeded for 99% of the hours in a year.
Based on guidelines, our pump will supply all the heating and hot water needs for our house down to -4.5°C; beyond this temperature it will utilise a back-up which is our oil boiler. According to the documentation, our heat pump will continue to provide heat down to -20°C, aided when required by the oil boiler.
Based on calculations, our entire property requires 12.2kW of heat to keep it warm with outside temperatures of -3.3°C. At these levels, our operating costs should still be much cheaper than running off oil. As a point of reference, we’ve only dropped to around -2C this year, and that’s generally been for a few nighttime hours. This means we’ve been running our heating quite efficiently.
The past four months
Over the past four months (September 1-December 31, 2019), which have generally been cold, miserable, damp and gloomy, we’ve been saving £150 per month on heating versus oil at the same time last year (you can get more info in this post and also see a full autumn review of our heating system). This has meant that we’ve saved around £600 this autumn/winter, and we expect that figure to rise to over £1,000 by spring.
Our heating costs in the summer, mainly hot water, are close to zero because our solar PV takes care of that. The pump, if it needs to heat hot water at night is extremely efficient because ambient temperatures are very warm.
We also signed up for the domestic renewable heat incentive (RHI) scheme and we will be getting financial reimbursements over the course of the next seven years. We received our first payment a few weeks ago for over £600, with more payments expected on a quarterly basis for the next seven years. Once we get to April 2020, we’ll have a detailed picture on how quickly we’ll get our investment back.
Summation and final verdict
So here’s the deal. If you are thinking of putting in an air source heat pump for a short period of time like 1-2 years I don’t think that you will get a significant return or benefit on your investment. When we spoke to real estate agents we asked them if an air source heat pump would add equitable value to the property in the short term and the answer was no. The consensus is it’s a nice thing to have that may make the property easier to sell, but people aren’t generally willing to pay extra for an ASHP that’s been installed. The same thing applies to solar panels.
I think this stems from lack of knowledge about the benefits of ASHPs. While many people are on the “green” bandwagon, they don’t fully understand that running costs can be cheaper.
To conclude, air source heat pump installations are a long-term play. You will save on your heating costs but it does not add immediate or significant financial value to your property. Having had the air source heat pump for under one year now, I think that the 7-8 year mark is the point at which we will fully recoup our initial outlay provided that the pump continues to run efficiently and without issues, and that we can retain low electricity tariffs.