- The Building Regulations 2000. Approved document L2A. Conservation of fuel and power in new buildings other than dwellings. 2010 edition. The Stationery Office. Free download available.
- BS EN ISO 13789:1999 Thermal performance of buildings – Transmission heat loss coefficient – Calculation method.
- National Calculation Methodology (NCM) Modelling Guide (for buildings other than dwellings in England and Wales). 2010 Edition. January 2013 revision.