Conservation of fuel and power: Approved Document L, Volume 1 — Dwellings

O N L I N E V E R S I O N R24-27C Buildings that contain multiple dwellings 1.4 For a building that contains more than one dwelling – for example a block of flats or a terrace of houses – an average target primary energy rate, target emission rate and target fabric energy efficiency rate may be calculated as an alternative to individual target rates for each dwelling. The floor-area-weighted average of the target primary energy rate, target emission rate and target fabric energy efficiency rate for all the dwellings in the building should be calculated using the following formula: [(target primary energy rate × floor area) + (target primary energy rate × floor area ) + 1 1 2 2 (target primary energy rate × floor area ) + …] 3 3 (floor area + floor area + floor area + …) 1 2 3 1.5 The average target emission rate should be calculated using the formula above but replacing target primary energy rate with target emission rate. The average target fabric energy efficiency rate should be calculated using the formula above but replacing target primary energy rate with target fabric energy efficiency rate. 1.6 Calculating an average target primary energy rate, target emission rate or target fabric energy efficiency rate for separate buildings on the same site is not considered a reasonable method to show compliance. District heat networks 1.7 For a dwelling that is connected to an existing district heat network, the notional building used to calculate the target primary energy rate and target emission rate can use the same primary energy and CO emission factors for the heat and hot water delivered to the dwelling as used in the 2 calculation of the dwelling primary energy rate and dwelling emission rate. All other aspects of the notional building, except wastewater heat recovery, should remain as outlined in Table 1.1. NOTE: For a dwelling that is connected to a new district heat network, the notional building used to calculate the target primary energy rate and target emission rate should follow the specification shown in Table 1.1. Notional dwelling specification 1.8 The full notional dwelling specification used in the Standard Assessment Procedure is given in Appendix R of SAP version 10: https://www.bregroup.com/sap/sap10/. The notional dwelling specification is summarised in Table 1.1. Building Regulations 2010 Approved Document L Volume 1, 2021 edition 11 O N L I N E V E R S I O N