Part L of Building Regulations (Conservation of Fuel & Power)

Part L sets the energy efficiency standards required by Building Regulations. It controls the insulation values of building elements, the allowable area of windows, doors and other openings, air permeability of the structure, the heating efficiency of boilers and the insulation and controls for heating appliances and systems together with hot water storage and lighting efficiency. It also sets out the requirements for SAP (Standard Assessment Procedure) calculations and Carbon Emission Targets for dwellings.

In addition to insulation requirements and limitation of openings of the building fabric, the part also considers solar heating and heat gains to structures, it controls heating, mechanical ventilation and air conditioning systems, lighting efficiency, space heating controls, air permeability, solar emission, the certification, testing and commissioning of heating and ventilation systems, and requirements for energy meters.

Building regulations are administered separately in England, Scotland and Wales.

Go to resource

DCLG, Building Regulations

* * * * * (1)Report a broken link


Please Log In or Sign Up to rate this resource or make a comment.

Monday, 29th April 2013

Mary Rawlinson, DPP

This is Part L as it stands, the current regulatory framework for Building Control teams across England and Wales. There are 4 Approved Document parts to it:
L1A: Conservation of fuel and power (New dwellings) (2010 edition)
L1B: Conservation of fuel and power (Existing dwellings) (2010 edition)
L2A: Conservation of fuel and power (New buildings other than dwellings) (2010 edition)
L2B: Conservation of fuel and power (Existing buildings other than dwellings) (2010 edition)
There is expected to be a revised version published later in 2013 which increases the standards further.



Department of Communities and Local Government (DCLG)

(9) Resources

Added by

Richard Twinn
Policy & Public Affairs Officer
(16) Resources

View profile


Part L, although sounding rather dry, has been the starting point for a huge amount of innovation in the sector in recent years, because of the association with the trajectory towards zero carbon homes and buildings. The foundation for any low carbon home or building is high levels of energy efficiency from the building fabric to minimise energy demand – which is covered by Part L of the Building Regulations.

Ongoing debate around Part L and future requirements can be both highly technical, and politically contentious. UK-GBC regularly advocates an ambitious position on Part L to Government, through consultation responses and other forms of communication. Read more about our position here.

Our Sponsors

Ecobuild   Marks and Spencer Mitsubishi Electrica Wates foundation