If your heating bills are high then it might be worth checking the insulation in your loft. If you are not confident you can do it safely then ask a neighbour or friend or family member to help you. Try not to disturb the insulation, since some properties can have insulation that may be irritant or dangerous. Just note down what type it is (take a photo if you don’t know) and the thickness it is from the ceiling below. You should be able to do all this from the access hatch without needing to get into the loft (if you do go in the loft then be aware that the insulation is very often resting on the fragile gypsum boards of the ceiling below – walking and moving in the loft needs to be done with care and only on the structural beams or joists).

If you have fibre or soft wool-like insulation then you should have at least 270 mm to achieve the latest UK guidance. Many people use 300 mm as a rule of thumb. This is 300 mm thickness in its soft as-rolled condition. Do not compress the insulation or lay boards over it and compress it as it will not be effective. Boarded lofts need to have a small gap under the board to the insulation (say at least 30 mm) to ensure that insulation underneath is not compressed.

If you have insulation in poor condition (damp, evidence of insect or animal damage or droppings) then you may need to have the insulation removed and to start again with the insulation. In this case it may be worth getting someone in to help. Any roof leaking issues must be addressed prior to laying new insulation. If the insulation is very old then it might be of a dangerous type and it is always a good idea to get someone knowledgeable to check it prior to anyone touching it. Read section 1 of our reference article on insulation to get up to speed with loft insulation.

The improvement in heat retention in the property can be impressive. Example 1 of our reference article on U-values show that a bare loft may have a U-value of 3.4 W/(m²K), a loft with 100 mm layer between the joists has a U-value of 0.38 W/(m²K) and a loft with an additional 150 mm layer across the joists has a U-value of 0.16 W/(m²K). In heat loss terms, if the loft area is 20 m² (this is a small loft, and it could be even double this) and the outside temperature is 0°C and the home heated to 20°C then that is 1360 W (uninsulated loft), 152 W (100 mm insulation) and 64 W (topped-up loft insulation). Over 24 hours this would cost £2.90 or £0.32 or £0.14 in gas bills (using 8p/kWh gas unit rate and a gas boiler efficiency of 90%). The top up alone is worth 19p per day and roughly £35 to £40 per year.

Section 1 of our reference article on insulation indicated that missing insulation is more common than people are aware of around the exterior edges of rooms close to the soffit boards (where the roof tiles or slates start on the external walls). The other area that insulation may be completely missing is above tight gable dormer windows. The roof timbers are so tight in some of these gable dormer sections that access to inspect is really difficult, let alone space to lay insulation in there. If you have these and the rooms they are in always feel cold then that might be your problem. Just one of these with a ceiling area of 2 m² would lose 136 W, perhaps as much as the entire rest of the loft!

So if you think your loft insulation is inadequate, get in touch with your energy supplier and see if they can help. If you do not qualify for free help – do not worry – the payback from energy savings make this change worthwhile whether you pay someone to do it for you or perhaps even do it yourself.