Revised Building Regulations which improve energy efficiency standards for new buildings come into force on April 6.

The revised Part L (Conservation of Fuel and Power), which was laid before parliament on March 15, will increase energy efficiency levels by 20%. It will also introduce air pressure testing for new buildings, simplifying the process for calculating energy peformance.

Yvette Cooper, housing minister, said the revised bill would make a “significant contribution” to the government’s effort to tackle climate change, as well as benefit householders through reduced fuel bills.

The revisions set overall performance standards for new building, as well as work to existing structures, but do not prescribe particular methods for meeting them in order to allow flexibility in design.

The government has launched the largest ever training programme for new Building Regulations to help builders adapt to the changes.

All major building work without full planning permission before April 6 must comply with the updated Part L, while developments with existing planning approval must begin construction within 12 months to comply with the earlier version of Part L (2002).