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Energy-efficient homes

Energy efficiency

There are a number of different considerations around the subject of energy efficiency, including whether or not an application for Building Regulations (BR) approval might be required for specific projects. In addition, homes must be rated for energy and water efficiency.

For more information, see our 'Code for Sustainable Homes' and 'Building regulations' sections.

More information about the range of energy efficiency measures possible can be found on the Energy Saving Trust's (EST) website.

Solar panels

If you wish to add a solar panel to the roof of your home, BR approval is likely to be needed. The adequacy of the existing roof to carry the load (weight) from the panel will need to be checked and proven. Some strengthening work may be needed. Also, as for example, roof tiles will be removed or omitted to locate and fix the panel(s), the reinstatement should ensure the roof has adequate weather resistance.

Internal lights

Fixed internal lighting will need to have reasonable provision made to obtain the benefits of efficient electric lighting whenever:

  • A dwelling is extended
  • A new dwelling is created from a material change of use
  • An existing lighting system is being replaced as part of re-wiring works

A way of making your internal lighting more energy efficient is to provide lighting fittings (including lamp, control gear and appropriate housing, reflector, shade or diffuser or other device for controlling the output light) that only take lamps having a luminous efficacy greater than 40 lumens per circuit watt.

The types of light fittings that would meet the above requirements are fluorescent and compact fluorescent light fittings. Fittings for GLS tungsten lamps with bayonet cap or Edison screw bases, or tungsten halogen lamps would not.

A general way of meeting these requirements is to provide one fitting for every:

  • 25m2 of dwelling floor area (excluding garages); or
  • one per four fixed light fittings.

Lighting fittings in less used areas such as cupboards and other storage areas, would not count towards a fitting. If constructing an extension, it may be more appropriate to install the energy efficient light fitting in a location that is not part of the building work. e.g. to replace the fitting in the hall or landing when creating a new room - depending on the likely extent of use of the new room light compared to the hall or landing.

Insulation in a loft

Installing insulation to your loft area requires an application for BR approval. Care should be taken not to block any ventilation at the edges (eaves).

Re-cycling water tanks

These are tanks that recycle surface water (rainwater) that is collected from the roof and ground, so that it can then be re-used within the house for other uses such as toilet flushing or general washing. These tanks are generally placed underground in the rear garden if there is space. An application for BR approval is required to check the new drainage system running to the tank.


Any new radiator installed will require a thermostatic radiator valve (TRV) to be installed. A TRV gives better control over the individual room temperatures. It is also encouraged to fit TRV's to existing radiators.

Pipe lagging

Pipe lagging is the insulation that covers pipes and does not normally require BR approval.

Thermal elements

Making significant changes to thermal elements would normally require BR approval and require the thermal insulation of the element to be upgraded to a reasonable standard. The following are defined by Regulation 2(a) of the BRs as being thermal elements:

  • Walls
  • Floors
  • Roofs

The extent to which the work on the element is controlled and the amount of upgrading needed depends on what the element separates (i.e. what is each side of it) and how much renovation of the element is proposed.


It is now a general aim to make our buildings as energy efficient as possible. You are required to install efficient electric lighting to your house in specific circumstances including:

  • When your dwelling has been extended
  • When your existing lighting system is being replaced as part of re-wiring works

An example of efficient lighting is where reasonable provision should be made to enable effective control and/or use of efficient lamps such that either lamp capacity does not exceed 150 watts per light fitting and the lighting automatically switches off when there is enough daylight and when it is not required at night; or the lighting fittings have sockets that can only be used with lamps having an efficacy greater than 40 lumens per circuit-watt.

External lights

If you are installing an external light which is supplied from your electrical system and fixed to the exterior surface of your house, then you should ensure that reasonable provisions are made to enable effective control and/or use of energy efficient lamps. Two options for achieving this are:

  • Installing a lamp with a capacity which does not exceed 150W per light fitting and the lighting automatically switches off both when there is enough daylight and also when it is not required at night
  • Ensuring that the lighting fittings you use have sockets that can only be used with lamps having an energy efficacy greater than 40 lumens per circuit-watt

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