ACP Analysis: Energy Consumption and running costs of Electric Space Heating Systems
14 October 2022
Member of ACP, Professor John Counsell's report "Energy Consumption and Running Cost of Electric Space Heating Systems" examines the operating costs and carbon intensity of various electric heating systems to determine the most pragmatic option for a range of three compact property types. Professor Counsell is an independent researcher with over 30 years of experience in the design, development and assessment of electric heating systems and their controls. The running costs, CO2 emissions, Primary Energy Factor (PEF) used in the comparison studies described in this paper have been estimated using SAP10.1 beta FSAP software aimed to replicate the calculation method: Standard Assessment Procedure 10.1
The results of his study demonstrate that for a typical one or two-bedroom flat or apartment built to the latest building regulation standards, and with a floor area of up to 65m², the running cost differential between a house fitted with an electric resistance heating system compared with an MCS certified heat pump can amount to less than £100 per year (2021 typical energy prices). Given that electric resistance heater systems have an average design lifespan of more than 25 years, the contention is that for properties of this type, the capital cost premium to fit a heat pump instead of electric resistance heating, combined with the servicing cost and replacement cycle differentials make the economic justification extremely difficult. However, for the larger three bed property which was modelled, the choice of a heat pump for space and water heating in preference to electric resistance heating, in economic and emission terms, is demonstrably more defensible.
The results also clearly show that for the smaller property types, domestic hot water plays a very significant role in total heating cost and CO² emissions, in most cases overshadowing the space heating contribution. Significantly, aside from when using certain heat pump systems, employing instantaneous water heating such as electric showers instead of stored hot water, offers a notable reduction in costs and emissions in every situation, and this advantage is carried over in SAP, which rewards instantaneous over stored hot water for small property applications.
