"Promoting a better use of energy                   
                  to counter climate change"

Energy Advice > Saving Energy > Insulation

Save money by adding insulation to your home

In a typical British home, around one-third of the heat produced by a central heating system is rapidly lost through the roof, ceiling and walls. This does not have to happen: simple insulation measures can eliminate this loss almost completely.

Through the roof

• As much as 20% of your energy bill can be saved by good loft insulation. Lofts should be insulated to a minimum depth of 150mm (6 inches) - preferably 200mm (8 inches) - and this can be done by either a contractor or DIY. Mineral wool (such as Rockwool or Rocksil), fibreglass and recycled paper products all work well. Remember to wear a facemask, goggles and protective clothing if you do it yourself, and leave sufficient gaps around the eaves to avoid condensation.
  
• Do not insulate under water tanks that may freeze and ensure all pipework and the loft hatch are insulated.

Through the walls

• Most heat (up to half the total) is lost through the walls of an uninsulated house. Wall insulation can reduce this loss by two-thirds and make your home more comfortable. If there are cavity walls they can usually be safely filled with insulating fibre, beads or foam.
  
• If the walls are solid, internal insulation (often applied in the form of an insulated board fixed to the wall) is highly effective, but means rooms have to be redecorated and may lose architectural detail. This can be done by competent DIYers and may be done on a room by room basis at the same time the home is redecorated. External insulation usually needs planning permission and should only be carried out by specialist companies.

Through the windows & doors

• Draughts are the most uncomfortable and obvious signs of a badly insulated house and can be fixed easily with either draughtproofing, secondary or double glazing. Don't be tempted to save money by fixing cheap foam draughtstripping, as it only last a couple of years before it becomes permanently compressed. Polypropylene tubes are a little more expensive but last longer and are more effective. BEWARE! Don't add draughtstripping to a room with an open fire or a gas fire that does not have a balanced flue, where there is no airbrick near the fire. Fires need a good flow of air to burn safely and there is a danger of being poisoned by Carbon Monoxide fumes if a room is too tightly sealed.
  
• Double glazing is the UK's most popular energy saving measure, although it actually saves less from a typical fuel bill than putting in (much cheaper) cavity wall insulation. If your windows need replacing, make sure that you specify "Low-e" glazing, which has a special heat-reflective coating between the two panes of glass. This will reduce heat loss through the glass by nearly half. You can also ask for Argon gas filled windows: argon is a gas found naturally in ordinary air, but it transmits heat much less readily than the other gases in air, so helps you save even more money. Finally, look at the air gap between the panes; 6mm or 8mm are not really adequate, but 12mm to 20mm are much better are stopping heat losses (and also for reducing noise transmission).
• Through the floor

• You can lose as much as 10% of heat through uninsulated floors. There are a number of ways of solving this problem, including insulating blankets under suspended floors and laying boards over concrete floors - ask your energy advisor for details.