Home Insulation Explained

Insulating your home is essential if you want to keep it warm, and a well-insulated house will be more cost-efficient. This guide outlines some key types of insulation and approximately how much different insulation methods cost. 

Insulating your home will make it warmer and more comfortable. It can also mean that you hear less outside noise, such as vehicles. If the house is warmer through insulation, you will spend less on energy bills to warm your home. Effective insulation is one of the best ways of decreasing your energy bills, as some key insulation measures are ‘low cost’, meaning that they pay for themselves in less than five years. Not only is this beneficial financially, but it also reduces the negative impact on the environment. 

Heat can be lost through the roof, walls, floor, windows and door. An uninsulated house loses a quarter of its heat through the roof, but this can be prevented with loft insulation. Most modern properties already have wall insulation, but older properties may not. You can also get floor insulation.  

The amount of heat being lost from different parts of the home will depend on the type of house or flat you live in. Usually, the house will lose the most heat (between 30-40%), the roof will lose around 25% and the floor, of the lowest storey, about 10%. 

Loft insulation typically costs about £400, but you could save up to £250 a year on energy bills, so in the long-term, you will save money. It is usually effective for at least 40 years. 

The majority of lofts are insulated with rolls of foil-backed or mineral fibre. The first layer is fitted between the beams, and a second layer is put down across the joists at right-angles. If you use the loft for storage, you should lay boards over the joists. 

If you have walls with a cavity, they can be filled with polystyrene, mineral wool or foam. Cavity wall insulation costs vary, but it is usually £700 for a detached house, which can save you £250 per year on gas and electric bills. If your home was built before the 1920s, it is likely to have solid walls which can be insulated either from the inside or outside. This will be more expensive, but also cost-effective in the long-term. 

You generally only need to insulate the ground floor. Homes with solid concrete floors can have rigid floor insulation laid on top, and timber floors can be insulated by pulling up the floorboards and installing mineral wool insulation supported by netting between the beams. 

Heat can escape through draughts around windows, external doors and loft hatches. You can draught-proof your home through buying tools such as foam strips for windows and letterbox brushes from DIY stores. This is one of the cheapest and effective ways to save energy. This can also be done by a professional who will know the best materials to use.

Pipe insulation involves a foam tube that covers exposed pipes between your hot water cylinder and boiler. This reduces the amount of heat loss and water remains warmer for longer. You can usually find the correct size from a DIY store and place it around the pipes. 

Planning permission is usually not needed to fit insulation into your home. There may be some restrictions if you live in a listed property or conservation area in terms of solid wall insulation and glazing. Also, you should ensure that any work you do complies with your building regulations. Check with your local council’s building control department to find out what these regulations are. 

This depends on the type of insulation, as some can be completed yourself. If the insulation work needs to be professionally carried out, search for a company that is a member of an organisation such as the National Insulation Association to do this. This will mean that they have reached certain standards, and it is also good to check whether the work comes with a recognised guarantee. 

Many energy suppliers pay towards the cost of loft and cavity wall insulation, allowing you to get free or cheap insulation. You do not always have to be a customer to be eligible for this, but it is usually required that you receive income-related benefits. Check on energy suppliers’ websites to find out about what help is on offer, and to see if you are eligible. For example, with the government’s ECO scheme, you can get free loft and cavity wall insulation if you are eligible to improve your home’s energy efficiency and are a customer of certain energy suppliers.