New Build Heat Standard

Building conversions

The New Build Heat Standard (NBHS) applies to some conversions of existing buildings. 

A conversion is a particular change in occupation or use of a building, for example changing an office to a hotel or an attic into a bedroom. Building regulations define and treat conversions differently to alterations and extensions. 

If you are converting a building, the NBHS will apply if:

• you have a direct emissions heating system in the building or area of the building you are converting, and 

• it is ‘reasonably practicable’ to install a clean heating system 

For more detail see the Building Standards Technical Handbooks. 

A temporary direction allowing bioenergy heating systems including wood burners and peat-burning systems to be installed in new-build homes also applies to conversions.

Local Authorities Building Standards are responsible for considering all building warrant applications.

Proposed changes – not yet law 

We are proposing changes to the NBHS. Under these changes, the NBHS will not apply if you are converting a building which already has a bioenergy heating system like a wood burner, or peat main heating system.

It may still apply if you are converting a building with other types of direct emission heating systems – this will depend on whether your project fits within the requirements set out by the Building Standards technical handbooks. These will be updated to reflect any changes in regulations ahead of January 2025.

Building warrants applied for before April 2024 

The NBHS applies to building warrants applied for on or after 1 April 2024. A building warrant is legal permission to start building work or convert a property and lasts for 3 years.

A building warrant can be extended for an initial period of 9 months. Further extensions are at the discretion of the building standards officer. This means not all new buildings completed after 1 April 2024 will meet the NBHS due to developments being at different stages in the building process. 

New developments that applied for a building warrant before 1 April 2024 may continue to install direct emission heating systems for as long as the issued building warrant remains valid.