Post RHI announcement Tom Garrigan of BSRIA looks at the schemes available for air-source heat pump schemes and how they can benefit system specifiers.
The recent RHI announcement may have put air-source heat pumps on the back burner for the next 12 months at least, however the technology is still set to increase in popularity.
There are two main schemes specifically run in the UK: the Microgeneration Certification Scheme (MCS), and the Enhanced Capital Allowance (ECA) scheme. The MCS, supported by the Department of Energy and Climate Change, focuses on product and installer certification, with grants available to applicants who meet the required criteria.
Grants of up to £2500 per property are available to households, community organisations, public, private and not for profit sectors. Heat pumps with a capacity of up to 45 kW are accepted, however each technology has a minimum COP (co-efficient of performance) requirement.
All thermal performance tests are carried out in accordance with European standard EN 14511, and heat pumps have to be tested by a UKAS accredited or similar test laboratory. In addition to thermal performance tests, safety tests must also be conducted in accordance with Part 4 of EN 14511.
Sound characteristic tests are also a requirement of the MCS and have to be carried out in accordance with ENV 12102. This scheme also requires a factory production control visit to further ensure the consistent quality of the accepted products.
When applying for the ECA scheme, managed by the Carbon Trust on behalf of the Department of Energy and Climate Change, a manufacturer can self-declare the COP of their unit at the prescribed EN 14511 test conditions. Provided the declared values meet the minimum performance criteria for each technology, the heat pump will be added to the Energy Technology Product List (ETPL).
The ETPL is audited annually, and a selection of units from each technology and multiple manufacturers are chosen to be tested by an independent test laboratory with UKAS accreditation or similar. When the units are tested independently, the manufacturer declared values must be at least 95 per cent of the independent test results in order to remain on the ETPL.
Companies buying listed products can claim an enhanced capital allowance which is a tax benefit against the purchase cost of the heat pump and other direct costs such as delivery cost, installation and professional fees. This tax benefit is only available to companies that pay UK Corporation Tax.
Both the MCS and the ECA scheme require the same test point for air-to-water, water-to-water and brine-to-water heat pumps.
Two schemes are running in Ireland, both managed by Sustainable Energy Authority of Ireland (SEAI): the Greener Homes Scheme (GHS) and the Home Heating Appliance Register of Performance (HARP).
Grants are available through the Greener Homes Scheme (GHS), for homes occupied prior to the 30 June 2008. The required water-to-water and brine-to-water test condition for the Greener Homes Scheme is the same as the MCS and ECA scheme. However two test points are required for air-to-water heat pumps.
Part of the Home Heating Appliance Register of Performance (HARP) scheme focuses on heat pumps, and each technology has a minimum COP requirement based on the average of multiple test points, for example air-to-water heat pumps require three test points in accordance with EN 14511.
The performance data from the thermal performance tests is used to determine the Building Energy Rating (BER), which was made compulsory for homes being sold or rented from 1 January 2009.