Seal the sneaky gaps that leak your heat all winter
Draughts make a warm room feel cold and pull your heating bill up. A weekend with a few euros of foam strips, a door brush and a draught snake fixes most of them for good.
A draught is heat you’ve already paid for, walking out of the building. Warm air rises and escapes through gaps high up — loft hatches, the tops of windows — and cold air is drawn in low down through door bottoms, letterboxes and worn seals to replace it. The result is that maddening combination of a thermostat reading 21°C and a room that still feels chilly, with cold ankles by the sofa.
The fix is among the cheapest in the home-energy toolkit. Self-adhesive foam strips, a door brush and a chimney balloon together cost less than a takeaway, and most of the work is just cleaning a surface and pressing on a strip. The payoff is double: a lower bill, and a home that simply feels more comfortable and less breezy, which often lets you nudge the thermostat down a degree on top.
The one rule worth repeating is that some ventilation is deliberate and necessary. Trickle vents, extractor fans, air bricks and the airflow around gas appliances are there to carry away moisture and combustion gases — seal those and you trade a small heating saving for damp, mould or worse. Done sensibly, you’re closing the accidental gaps while leaving the intentional ones open, which is exactly the balance a healthy, efficient home needs.
How to do it
- On a windy or cold day, run the back of a damp hand around door and window frames, the letterbox, the loft hatch and any unused fireplace — you'll feel the cold streams of incoming air.
- Clean the frames, then stick self-adhesive foam or rubber weatherstrip around the edges where the window or door closes against the frame, so it compresses into a seal.
- Fit a brush or rubber-blade draught excluder along the bottom of external doors, and a brush plate behind the letterbox flap.
- Block the big single offender — an unused chimney — with a removable chimney balloon or wool draught excluder, and pop a draught snake along leaky internal doors to cold rooms.
- Leave trickle vents, extractor fans and air bricks clear — these are deliberate ventilation, not draughts, and you need them to keep the air healthy.
Pro tips & pitfalls
- Don't seal a home airtight. Kitchens, bathrooms and any room with a gas appliance need airflow to clear moisture and combustion gases — over-sealing invites damp and mould. The goal is to stop uncontrolled draughts, not all ventilation.
- For a quick test of where strips have worn out, hold a lit candle or incense stick near a closed frame on a breezy day and watch the flame or smoke lean.
What it's good for
Good for the planet
- Saves energy Uncontrolled draughts can account for a meaningful share of a home's heat loss; sealing them means your heating warms the room, not the street.
- Cuts CO₂ Less heat leaking out means less gas or electricity burned to replace it, every cold hour of the winter.
Good for you
- Saves money Draught-proofing the main gaps typically costs €20–60 in strips and excluders and often pays back within a single heating season.
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