Draughts are bad news and you should work to seal them up, they are uncontrollable ventilation and they waste your heat, they reduce comfort and they bring in dust and dirt from outside.
To find them first of all look for them, if you can see daylight through a letter plate, keyhole or beside a door there will be a draught there. Look in the top of your airing cupboard, often there will be gaps or holes through the ceiling into the loft. Any crack that is discoloured black could well have a draught coming in through it, look under window sills, round window and door frames, under thresholds, round pipes etc.
The next method of locating draughts is to feel for them, dampen the back of your hand and hold it close to a socket outlet, window sill board, window sash, skirting board or crack, if it feels cold then then there is very likely a draught. Other methods of finding draughts include using a candle flame, puffing with talcum powder, using tracer smoke matches or pellets. You can also use a thermal imaging camera to find cold places, but with all the other methods it is not generally necessary to use one.
Places to look are; round, through and under doors, windows and frames, beside pipes, under skirting boards, through electrical fittings, between floorboards, key holes, and any gaps or cracks.
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