Conservation of fuel and power: Approved Document L, Volume 2 — Buildings other than 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 building, 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 5 or Section 6. b. The test data should be certified by a notified body. 5.3 For heating and cooling systems, paragraphs 5.9 to 5.17 should be followed, in addition to system specific advice in Section 6. Replacement building services in existing buildings 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 The new LPG boiler has both lower CO emissions and primary energy than the oil-fired boiler being 2 replaced, and therefore complies. It is also at least as efficient as the minimum efficiency as set out in Section 6 of this guidance. 35 Building Regulations 2010 Approved Document L Volume 2, 2021 edition O N L I N E V E R S I O N