LISA Salmon taps up the Energy Saving Trust for their guide to insulating

ACCORDING to the Energy Saving Trust (EST,, in an uninsulated home, 45% of heat loss is through solid walls, 33% through other walls, 25% through the loft or roof space, and 20% through windows and doors, so properly insulating your home is an environmentally-friendly move that could save you a fortune over the years.

Here are the six main areas the EST says need insulating in the home, and how much you could save...

ROOF AND LOFT: Insulating the loft or attic is a simple and effective way to reduce heat loss and heating bills, and it should pay for itself many times over, says the EST. If access is easy and loft joists are regular, you can use rolls of mineral wool insulation. This will keep your house warmer but make the roof space above colder, meaning pipes and water tanks in the loft could freeze more easily, so you'll need to insulate them too. Also fit an insulated loft hatch and put draught-excluding strips around it. If there's damp a professional installer should be used.

How much can you save? Roof insulation costs are between £285-£395, and fuel bill savings can be between £115-£215 a year.

CAVITY WALLS: Heat will always flow from a warm area to a cold one, so the colder it is outside, the faster heat from your home will escape. Houses built from the 1990s onwards usually have wall insulation, but older houses may not and could be losing a lot of heat.

Most types of wall can be insulated, though you need to identify what sort of walls you have. If a house was built after the 1920s, it's likely to have cavity walls (two walls with a gap in-between). Older houses are more likely to have solid walls. You can tell which type of wall your house has by looking at the exterior brickwork: if the bricks have a regular pattern, the house usually has cavity walls, and if there's an alternating pattern, it probably has solid walls.

How much can you save? The EST says cavity wall insulation can cost between £330-£720 to install, depending on the type of house, and savings on heating bills can be anything from £65 a year for a flat to £250 a year for a detached house.

SOLID WALLS: Solid walls let through twice as much heat as cavity walls, but they can be insulated, either from the inside or outside. Internally, rigid insulation boards are fitted to the wall, or a stud wall is built and filled in with insulation material. Externally, a layer of insulation material is fitted to the wall, then covered with a special type of render or cladding.

How much can you save? Solid wall insulation usually costs more than insulating a standard cavity wall, but heating bill savings are bigger. The EST says external wall insulation costs between £8,000-£22,000 and internal costs £4,000-£13,000. Savings can be anything from £115-£415 a year,

FLOORS: You can seal the gaps between floors and skirting boards yourself with a DIY store sealant. Older homes are more likely to have suspended timber floors, which can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists. Many homes, especially newer ones, will have a solid concrete ground floor. This can be insulated when it needs replacing, or can have rigid insulation laid on top.

How much can you save? Insulating the floor can cost anything from £950-£2,200, and savings range from £25-£65 a year.

TANKS, PIPES AND RADIATORS: Lagging water tanks and pipes and insulating behind radiators reduces the amount of heat lost. Fitting a hot water cylinder jacket is straightforward, says the EST. Pipe insulation is simply a foam tube that covers the exposed pipes between the hot water cylinder and boiler. It can be bought from a DIY store and slipped on.

How much can you save? Installing a hot water tank jacket on an uninsulated tank will cost about £15 and save around £89 a year.

DRAUGHT-PROOFING: Draught-proofing is one of the cheapest and most effective ways to save energy, and it's as simple as using sealant to block unwanted gaps around areas including windows and doors, and around pipework leading outside.

How much can you save? Professionals can draught-proof your home at a cost of around £200, but it's often easy and much cheaper to do it yourself. Make sure you don't block any intentional ventilation. Draught-proofing around windows and doors could save around £25 per year.

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