In the UK almost all new domestic and commercial properties are subject to one or more forms of regulation which, amongst many other things, require them to have a certain level of energy efficient lighting.

Building Regulations
Part L of the current building regulations relates to energy consumption and applies to domestic and commercial new builds and extensions. In the case of domestic applications the requirement is for one energy efficient light per 25 square metres, or one in four of the total light fittings, whichever is the greater. Roughly speaking this equates to 25% of lights needing to be energy efficient. Spaces such as garages and store rooms cannot be included within this calculation.

For commercial buildings the regulations are slightly more complex. Rather than being based on number of fittings, an average overall light output of 45 lumens per circuit watt or more is required for the lighting scheme. In some cases (bars and hotels for example) this increases to 50 lumens. Essentially, this means that most lights will need to be energy efficient.  

Code for Sustainable Housing
From May 2008 it became mandatory for all new homes to be rated against this code. The code measures the sustainability of a new home setting minimum standards for energy and water use. A star rating system (1 to 6 stars) communicates the overall performance of a building. This provides homebuyers with better information about the environmental impact of their new home and potential running costs.  Similarly it provides builders with a means of differentiating their homes from others on the market.

Energy efficient lighting falls within the energy and CO2 emissions element of the code with varying requirements depending on which star rating is aimed for (1 is lowest, 6 is the highest – a home rated 6 would have zero net carbon emissions during the year).