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

O N L I N E V E R S I O N L1(b), L2 Section 5: Minimum building services efficiencies and controls – general guidance New building services 5.1 For each new fixed building service in a new or existing dwelling, the efficiency of the service should be no lower than the value set out in Section 6. If a proposed service is not covered in Section 6, the service should be shown to be no less efficient than a comparable service that is covered. 5.2 Both of the following apply to the efficiency claimed for a fixed building service. a. The efficiency should be based on the appropriate test standard set out in Section 6. b. The test data should be certified by a notified body. 5.3 For heating and hot water systems in new dwellings, paragraphs 5.8 to 5.19 should be followed, in addition to the system specific guidance in Section 6. Replacement building services in existing dwellings 5.4 A replacement fixed building service should be at least as efficient as the value set out in Section 6 and should comply with either of the following. a. Use the same fuel as the service being replaced and have an efficiency that is not worse than that of the service being replaced. b. Use a different fuel than the service being replaced. The system should both: i. not produce more CO emissions per kWh of heat than the appliance being replaced 2 ii. not have a higher primary energy demand per kWh of heat than the appliance being replaced. Worked example Replacing an old oil-fired boiler with emissions of 0.298kgCO /kWh and primary energy of 2 1.180kWh /kWh at 85% efficiency with an LPG boiler with emissions of 0.241kgCO /kWh and primary PE 2 energy of 1.141kWh /kWh at 93% efficiency. PE CO emissions 2 Oil-fired boiler: 0.298/0.85 = 0.35kgCO /kWh 2 LPG boiler: 0.241/0.93 = 0.26kgCO /kWh 2 Primary energy Oil-fired boiler: 1.180/0.85= 1.39kWh /kWh PE LPG boiler: 1.141/0.93 = 1.23kWh /kWh PE Building Regulations 2010 Approved Document L Volume 1, 2021 edition 35 O N L I N E V E R S I O N