Fitting Insulation: A Complete Guide

The Loft, Tanks & Pipes
Insulate Walls, Windows & Floors

Confronted by a horrible heating bill? Insulate your home – or improve what you already have – and save money and energy.

By Sarah Warwick

Insulating The Loft

A whopping 25% of heat loss in an uninsulated home is through the roof. Even if you already have some loft insulation, adding more to bring it to the maximum level (for example 270mm for mineral wool insulation), is well worthwhile.

A loft that's easy to access and that doesn't have damp or condensation problems can be a DIY job. Depending on the type of insulation you put in, you may need protective equipment. Find out more about installing loft insulation at the Energy Saving Trust.

Beware Of Asbestos

If you are adding to existing insulation, beware of loose asbestos, which was used to insulate lofts. It's fluffy and may be blue-grey or white. Don't disturb it, but read our feature to find out what to do.

Call In The Professionals

If access is difficult, or you don't want to take the DIY route, call in a professional. Contact the National Insulation Association or the Energy Saving Trust.

Loft Insulation Types

There are several different types of loft insulation:

Rolls, such as mineral wool, or sheep's wool.
Loose fill, such as cork granules, vermiculite, mineral wool or cellulose fibre.
Blown insulation, made from cellulose fibre, recycled newspaper or mineral wool. This needs to be installed by professionals.
Rigid insulation boards, generally made from foamed plastic. Fitting needs skill.

For DIY insulation, look for Energy Saving Trust recommended products.

How Much Insulation Do You Need?

How much insulation you need depends on the product's thermal conductivity (K-value). The lower the thermal conductivity the better insulator it is, so you’ll need a thinner layer to get the same results as insulation with a higher value. If you’re DIYing, and need to calculate the depth of insulation necessary, check out the Energy Saving Trust's guide to insulation materials.

Loft insulation is effective for at least 40 years, and will pay for itself over and over in that time, according to the Energy Saving Trust.

Lagging Water Tanks & Pipes

Fit a jacket to your hot water cylinder and you can cut heat loss by over 75%. It should be at least 75mm thick, so it's worth upgrading from a thinner existing version, too.

You can also insulate exposed hot water pipes running between the cylinder and the boiler. If they’re hard to get at, call on a professional to help. You’ll find the foam insulation tubes at DIY stores. Find recommended products at Energy Saving Trust.