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HOME Keeping the heat in

Money falling through the  cracks?

Keep the heat in, the cold out and the energy bills down

In the home
Andy Wilson

As stated in the first of this series of articles on saving money on your energy bills (Tuesday, October 26, available on, the average house loses over one-fifth of its heat from air leakage. This ‘average’ figure can be quite deceptive, as it is boosted by the small percentage of houses that are actually quite airtight. Needless to say, some houses are much worse than the average, and this applies to new houses as well as older ones.
A simple air-leakage audit of your own home can be accomplished simply by holding a wet hand close to any suspect areas during a windy day. Remember, if wind can get in, then certainly warm air from the house can get out.

External doors are frequently among the worst culprits for air leakage. A sure sign is being able to see daylight around the edge of the door. In such cases, the air leakage test is hardly necessary. Fortunately the situation is often quite easy to remedy, by installing a weather proof strip to the door frame on the outside. The cost is less than €20 per door. The weather-proofstrip should be fitted when the door is closed and should butt tightly against the door.
For some doors (those with no protruding mat inside), it is also possible to fit a draught-proof brush strip along the inside of the door. This should also be fitted when the door is closed, and should be low enough to make a seal with the floor. 
Draught-excluder strips (the thin strips of foam sticky on one side) can be fitted along the jambs of doors and windows, to help make an even tighter seal.

Loft hatches are another place where warm air frequently escapes. Even fitting a draught-excluder strip – the kind mentioned above – between hatch and hatch frame can make a difference. Weighting the hatch by screwing on extra timbers can help it fit more securely.
Another trick is to fasten part of an old quilt to the top of the hatch, so that it acts like an extra draught-proof layer when the hatch is closed. The piece of quilt should be big enough to overlap the hatch by at least 100mm (4 inches) in all directions.

Probably the worst offenders in terms of air leakage are open fireplaces. They are like a big open hole up the middle of the house, and often are big and high enough to create a ‘stack’ effect that draws in cold air from outside whilst hastening the departure of any warm air within the building. And this is when the fire isn’t even lit!
When the fire IS going, some two-thirds to four-fifth of all combustion heat is lost up the chimney. The solution is simple (though not necessarily cheap): Replace all open fireplaces with solid fuel stoves. The stoves do not necessarily have to be super high-tech, as almost any stove with a tight fitting door will be at least twice as efficient as an open fire.

Crackas and gaps
The final bit of advice on air leakage is to go round all those cracks, gaps and holes on the inside of the building with filler or sealant. Large gaps in walls around pipes (check under sinks or in presses), around window frames (particularly under sills) may be plastered over with rigid filler, while gaps between materials where some movement is to be expected (between skirting and floor boards, for example) can be filled with a flexible sealant, such as silicone. Where holes are large, pieces of wire or plastic mesh can be pushed in first to provide a base for the filler.

NEXT TIME Insulation, and how to get best value for money.

Andy Wilson works part time as a domestic energy consultant. He can be contacted at 087 6714075 or email