Domestic Annual Heat Pump System Efficiency (DAHPSE) - Estimator - BETA

Dwelling heat loss

A dwelling's design heat loss is calculated using the average temperature of the coldest day of the year. For the purposes of this website, this is taken as a location with weather conditions that are typical for the UK (City of Leeds) and provides a temperature difference (between inside and outside the dwelling) of 24.2°C.

The table below provides estimates for dwelling design heat losses (in kW) for typical UK house types. The table values were determined via SAP assessment using English Housing Survey data, then rounded. Actual heat loss for a given dwelling should always be sought. For the purpose of efficiency estimates provided by this website, this loss should be calculated in accordance with the Standard Assessment Procedure (SAP), which is the UK's National Calculation Methodology for energy rating of dwellings. The heat transfer coefficient (W/K) - SAP Box (39) - for a given dwelling must be multiplied by 24.2°C to obtain a heat loss value.



NOTE: The graphs, images and performance estimates on this website are BRE’s interpretation of publicly accessible data, which are in part based on data submitted by product manufacturers and accepted in good faith. Some of the data supplied by product manufacturers is also used for the purposes of showing compliance with the European Union’s Ecodesign regulations (No 811/2013 and 813/2013) and therefore may be subject to market surveillance rules. BRE Group Limited and its subsidiaries, including but not limited to, Building Research Establishment Limited, make no representation or warranty as to the content of this website, its suitability for any use, or that it constitutes accurate data and/or advice.