Before you buy any seals, spend half an hour tracking down where the air is actually getting in. You will probably find the biggest leaks in places you would not have thought of.
Choose the right day
A cool, breezy day is perfect. The wind pushes air through gaps and the temperature difference makes it easier to feel.
Prepare the house
- Close all windows, doors and curtains.
- Turn off extractor fans and cooker hoods.
- Make sure no fires or boilers that need airflow are running.
Three simple tests
- The hand test. Run the back of your hand slowly along frames and gaps. It is very sensitive to a cool breeze.
- The tissue test. Hold a thin strip of tissue near the gap and watch for movement.
- The incense test. Hold a lit incense stick near the gap and watch the smoke. If it is pulled in or pushed out sideways, you have a draught. Keep it away from curtains and other flammable materials.
A room-by-room checklist
Doors. Check under the door, around the frame, around the keyhole and through the letterbox.
Windows. Feel round the sash, the handles and the gap between the frame and the wall.
Chimneys. Hold your hand in the fireplace opening. Cold air falling down is a clear sign.
Floors and skirting. Check along the edge of skirting boards and gaps between floorboards.
Loft hatch. Stand under it on a cold day. You may feel cold air from the loft, or warm air escaping upwards.
Pipes and cables. Check where they enter through walls or floors, for example under the kitchen sink.
Make a list
Write down each leak with a rough size: narrow gap, wide gap or hole. That tells you which product to buy:
- Narrow frame gap: draught tape
- Gap under a door: excluder or seal
- Open chimney: chimney excluder
- Letterbox: brush cover
Re-test afterwards
Once you have fitted the seals, repeat the tests to make sure you have closed the leak, and see if any new ones have become more obvious.