Thermal performance

Basements benefit from the surrounding ground improving their energy efficiency. As a consequence, the amount of insulation needed to reduce heat loss through a basement wall is less than that required on upper floor levels. The simple construction methods and minimum wall penetrations, associated with basement construction, also lead to minimal heat loss through cold bridging.

Studies, published in our Thermal Performance guidehighlight a potential 10 per cent saving in space heating for a two-storey house with a full ground basement compared with its threestorey equivalent above ground (both having the same amount of added insulation). The potential space heating saving rises to around 14 per cent for a single storey property with full basement, compared to its two-storey equivalent above ground.

Guidance for the design of basements to Part L1 (conservation of fuel and power) of building regulations refer to Guidance Document:Basements for Dwellings.

Concrete basements and thermal mass 

The heavyweight nature of basement construction can be utilised to naturally regulate the internal temperature of a home and can be part of an energy efficient strategy for controlling the temperature of the whole house. The Met Office has projected average daily temperature rises throughout the UK, indicating the increasing need for low energy solutions to cool homes, which heavyweight construction - including basements - is well placed to provide. For further information refer to The Concrete Centre publications Thermal Mass Explained and Thermal Performance: Part L1A.

Please refer to Part L1 (conservation of fuel and power) of our building regulations guide for further information. All information correct as of 2016 amendments.