Basements have an inherent airtightness, which is an advantage in achieving sustainable dwellings. Approaches such as Passivhaus require low air permeability and mechanical ventilation with heat recovery, as a means of improving the energy efficiency of the building fabric of dwellings. This is simply provided by basements, since the structure below ground is inherently more airtight.
Requirements for airtightness and ventilation are covered by Part F of Building Regulations.
The ventilation strategy for a basement should address:
- Extract ventilation
- Whole building/dwelling ventilation
- Purge ventilation (in response to a short-term increased need for ventilation).
For more information see Ventilation. All information correct as of 2013 amendments.