Approved Document Part L of the building regulations (conservation of fuel and power) is the driving force behind reducing carbon emissions in the domestic and commercial building sector.
Part L defines how buildings are constructed and the heating, ventilation and lighting installations within them in order to minimise their use of energy.
The regulations are divided into two areas for domestic (Part L1) and commercial (Part L2) buildings. The regulations are then further split for new buildings (Part L1A and Part L2A) and work on existing buildings (Part L1B and Part L2B).