Improved energy efficiency has been achieved by increased insulation levels, energy efficient heating systems, and the introduction of more renewable energy technologies. The positive gains from the above are worthless if hot air is still able to vacate the building and cold air enter without prior intention.
The control of air leakage must be given the upmost importance and plays a vital role in reducing energy consumption and CO~2~ emissions. Part L of the building regulations sets out requirements to follow to minimize air leakage, desired levels of air permeability, and makes the testing of air permeability mandatory.
This appendix addresses the issue of air leakage in new dwellings. The causes of air leakage and its effects on energy consumption and CO~2~ emissions are considered, and a strategy to minimise air leakage is outlined.
