Minimum non-domestic appliance efficiencies – England

Volume 1 and 2 of Approved Document L of the Building Regulations 2010 (ADL) will come into force for work carried out in England from 15 June 2022.

The importance of identifying the correct appliance efficiencies

Technicians should hold these freely available documents and become familiar with their contents as they are responsible for ensuring their work complies with the guidance therein. OFTEC’s technical department has created a technical notice that gives an overview of some key requirements of ADL.


Identifying minimum appliance efficiencies for oil and solid fuel-fired appliances, and heat pumps, is straightforward when these are installed in dwellings. However, identifying the minimum efficiencies that apply to oil boilers being installed in buildings other than dwellings is challenging (see ADL Volume 2, Section 6).

Rather than using readily available appliance efficiency data, government require a calculation to be undertaken to identify whether an appliance meets the minimum efficiency required. Unfortunately, the data to be used in the calculations is not currently available to installers! Government has promised to make the data available as soon as possible (at but cannot guarantee when. To assist technicians, OFTEC have worked with its members to create a list of appliances that meet the minimum efficiency requirements in buildings other than dwellings.

In summary, before specifying a boiler for a non-domestic building in England, check the list of suitable products found in the registered technicians area of