Heritage Energy Efficiency Tool (HEET)

Green Retrofit and Building Regulations

Most types of building work have to conform to theGovernment's Building Regulations. Part L of the Regulations relates to conserving energy and sets out a requirement to improve the thermal performance of the building. The accompanying Technical Guidance states that the aim should be to improve energy efficiency as far as is 'reasonably practicable'. Where this affects existing buildings, the regulations also set standards of energy-efficiency requirements for extensions and other significant changes to a building.

Energy efficiency measures may be required where a building is:

  • subject to a change of use,
  • where certain work is undertaken to a thermal element (wall, floor and roof) or
  • work is done to a controlled fitting or service: 'controlled fittings' include windows, doors or rooflights and 'controlled services' include systems used to manage the condition of the environment inside the building, e.g. heating system.

For instance, where a pitch roof is stripped and re-covered the regulations require this thermal element's performance to be improved as far as is reasonably practicable; where windows and doors are replaced the opportunity should be taken to upgrade them to help reduce the amount of energy required to reach comfort levels.

'Approved documents' describe how the regulations should be applied to specific types of building. Approved document L1B (domestic dwellings) and L2B (non-domestic dwellings) provide technical guidance to assist compliance with the functional requirements of the Building Regulations. Visit the Planning Portal to see these documents.

Listed buildings, buildings of historic interest located in Conservation Areas or of traditional construction may be exempted from some of the Regulations' requirements to prevent negative impacts on their character or the risk of deterioration of the building fabric and fittings.

There are many opportunities to improve the energy efficiency of your older building but you will need to think whether they are going to have a negative impact on its appearance, fabric, historic features or on the view from other buildings. You should consult our Building Control office for advice if you are planning building works to such a building. If energy efficiency measures are considered inappropriate as part of your work it is important to agree this with Building Control.

The Building Regulations will also apply where solar panels or PV arrays are installed on the roof of a building. Competent installer schemes exist for these works. A list of competent installer schemes can be found in schedule 3 of the Building Regulations 2010, point 17.