Q. I want to save on heating bills and insulate my loft properly. There’s already some insulation material there but no one is able to tell me how much I need. Can you help?

A. Run an electric car, stop flying, install a wind turbine — you can do all these things for the good of the planet but the single most important step you can make in the battle against climate change is to insulate your roof space. Compared with many other countries, our homes are dreadfully fuel-inefficient.

Without adequate loft insulation, about 25 per cent of heat disappears through the roof. By insulating a previously uninsulated house you stop up to one tonne of carbon dioxide entering the atmosphere each year.

As the sun comes out and the heating is shut off, it’s easy to forget winter chills and mounting power bills. Yet with DIY stores desperate to offload winter stock, there’s no better time to grab some rolls of insulation and head to the loft.

To conform to latest building regulations you’ll probably need 270mm of insulation in the loft — quite a hefty jump from the standard 50mm of the old days. First you need to carefully point a tape measure down from the top of your existing insulation to the ceiling slats or plasterboard. Then do the maths.

Also check on the consistency of your existing insulation — if it’s as flat and lifeless as a piece of yesterday’s toast, replace it. Remember always to wear a face mask: modern products tend to be dust and itch free but the older ones can cause nasty sneezing and scratching.

Ideally, 170mm of insulation should be laid between the ceiling joists, with the other 100mm cross-laid over the top. Investing in rolls of fibre is pointless if holes are left for precious warmth to seep through. Pay particular attention to areas where pipes come up into the loft.

Various products are on the market, most of them designed to last more than 20 years. The terminology of insulation is confusing: the most important things to look for are materials with a high “R” or “resistivity” value, and a low “U” rating — the relative speed heat is lost from a material. Insulation made up of recycled materials is now available — cellulose fibre from recycled paper, glass wool from recycled glass and products made from recycled plastic bottles.

With patience and care, insulating a loft should not be a difficult business. The Energy Trust (energysavingtrust.org.uk) has practical advice and information on grants available.

So, get up there and investigate. Not only will you be doing your environmental duty — you’ll also be saving money.

Keiran Cooke

Send your eco-dilemmas to greenandconfused@thetimes.co.uk.

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