Way back in July 2008 the Energy Savings Trust undertook a field trial of installed ground and air source heat pumps the results were varied, ranging from a few installations that performed very well, to a large number of installations which performed considerably less well. As a result the Microgeneration Certification Scheme Installation standards were written and became the backbone underpinning the heat pump industry and the associated Renewable Heat Incentive (RHI) grants and incentives.
Today, five years on from the start of that field trial, the importance of designing and installing renewable energy systems correctly is even more important as it not only affects your running cost but now, in light of the newly announced domestic RHI tariffs and calculation methodologies it affects the amount of payments you will receive.
As an example, we recently visited a homeowner, interested in a heat pump installation, he had commissioned an energy performance certificate (EPC), which highlighted his house as a band D with an estimated heating and hot water requirement of 23890 kWh per annum. The house was heated by an aging inefficient oil boiler and medium to high temperature radiators.
It had been suggested by others that he installs a high temperature air source heat pump operating at 60C flow temperature. Had he done this he would have paid for an installation with only a 1 star rating and a seasonal performance figure (SPF – average system efficiency over the year) of only 2.1, the resultant RHI payments would have been approximately £914 per year.
However, by spending time discussing his longer term plans for the house, we learnt that he wanted to remodel some of the rooms, lift the ground floor and put insulation in, this presented a perfect opportunity to install under floor heating. By working closely with the home owner and his builder, we were able to recommend a system which could operate at only 40C, thus improving his star rating to 4 and his seasonal performance figure to 2.7. This improved his estimated RHI payments to £1192 per year, which equates to an additional income of £1946 over the seven year life of his RHI scheme. Additionally, with a more efficient heat pump system his fuel cost savings also increase.
Seasonal performance figures and star ratings are set out in the MCS heat emitter guide.
If you would like to discuss a potential heat pump or any other renewable energy system, why not arrange for a survey with us?
by Mark Smith