England · Statutory guidance
Conservation of fuel and power: Approved Document L, Volume 2 — Buildings other than dwellings
Energy performance guidance for non-domestic buildings, covering fabric, services, controls and commissioning.
- Edition
- 2021 edition incorporating 2023 amendments · Volume 2; later editions and transitions on source page
- Search coverage
- 116 of 116 PDF pages · 2 OCR pages
Energy & sustainability
Open original PDF at page 107 Source wording and page order preserved. Drawings and table layouts remain available in the original PDF.
O N L I N E V E R S I O N E
Appendix E: Hierarchy for establishing
seasonal efficiencies of existing boilers
E1 When a heating system is being replaced in an existing building, paragraph 5.4 should be followed.
The seasonal efficiency of the appliance being replaced, if unknown, should be established by
following the hierarchy set out below. This is based upon the Non Domestic EPC Conventions for
England & Wales Issue 7.1.
1. Use Energy Technology List (ETL) product list part load values at 30% and 100% load.
2. Use current Product Characteristics Database (PCDB) values where available.
3. Use either manufacturer’s information or ‘boiler plate’ information or information from a
manufacturer’s technical helpdesk. Where a gross efficiency value is established for a non-
condensing boiler then a deduction of 0.05 (i.e. 5%) should be made to convert it to an
appropriate seasonal efficiency.
4. Use SAP 10 tables (up to 70kW output).
5. Use suitable SBEM defaults.
97
Building Regulations 2010 Approved Document L Volume 2, 2021 edition
O N L I N E V E R S I O N
Edition and local adoption determine which requirements apply. Use the publisher’s document for the complete clauses, diagrams and amendments.