Community Energy Literature Review

The UK Government’s Green Homes Grant scheme (GOV.UK, 2020) may have had some success in that it motivated some home owners to think about how they would make energy improvements to their homes if they could find a suitable contractor and received a grant.   One of the measures included in the scheme was the installation of a heat pump, of either the ground or air source type. Within the scheme these devices were classified as low carbon heat measures, and were subject to additional requirements. One was that a “minimum level of insulation is recommended to ensure the proper design and operation of the relevant technology in line with relevant standards” and another that all “heat pump systems must have a minimum Seasonal Performance Factor (SPF) of 2.5.” Ofgem (2021) defines the SPF as “a measure of the operating performance of an electric heat pump heating system over a year. It is the ratio of the heat delivered to the total electrical energy supplied over the year.” Ofgem exp...

A publication by the Energy Saving Trust, The heat is on : phase 2 , provides a useful introduction to heat pumps [1]. Its focus is on the performance of heat pumps installed in UK homes during the years 2010 and 2013, both air-source and ground-source types. An earlier trial (phase 1) demonstrated poor performance in some installations, and remedial action was taken prior to phase 2. Several measures of heat pump efficiency - Seasonal Performance Factors - are discussed. For the phase 2 trials the metric SPFh4 was chosen; the calculation of this SPF includes “the electricity supplied to the heat pump, all fans or pumps and electricity delivered to any incorporated auxiliary or immersion heater”. 38 heat pumps were used in phase 2, with average SPFh4 figures of 2.45 for air- source heat pumps and 2.82 for ground-source heat pumps. However, the performance range was wide, with SPFh4 values from 2.0 to 3.6 for ASHPs, and 1.6 to 3.8 for GSHPs. Consequently several of the sites...