A draught under a door is a small thing that adds up. You heat a room, and a steady trickle of warm air escapes under the door while cold air slides in to take its place. Over a winter, that costs you comfort, and it costs you money on heating.
The good news is that the under-door gap is one of the easiest draughts to fix.
The short version: close the gap between the door and the floor. A weighted draught stopper is the quickest, cheapest fix. It sits against the gap, stops warm air escaping and cold air pushing in, and needs no tools or installation. For the under-door gap, it is the easiest win in the house.
Why draughts under doors cost you heat
Draughts are uncontrolled air movement. Warm air leaves, cold air comes in, and your heater works harder to keep up. Older or draughty homes can lose roughly 15 to 20 percent of their heat through draughts, and draught-proofing is consistently listed among the cheapest ways to cut heating costs. The UK's Energy Saving Trust, for example, estimates that draught-proofing a home saves around £85 a year.
The gap under a door is one of the most common draughts, and one of the easiest to close. A 3mm gap doesn't sound like much. Run it across the full width of a doorway and it adds up to roughly the same opening as a small hole cut straight through the wall. That is heat you have already paid for, leaving the room.
Do draught stoppers actually work?
Yes, for the gap they cover. A draught stopper blocks air moving through the space under a door, so the room feels warmer and steadier almost straight away. The honest part: if a door is already well sealed, you will notice less. On a typical draughty door, you will notice a lot.
It won't replace insulation or double glazing, and it isn't meant to. It handles one specific, common gap, for very little money. If you want to dig into whether they're worth it and how to choose one, see do draught stoppers actually work.
What makes a good draught stopper
A good draught stopper does two things a towel can't. It stays in place, and it holds its shape. Weight keeps it pressed to the floor so it doesn't shift when the door swings. A dense fill stops it sagging flat and leaving the gap open. The material decides how long it keeps doing both.
| Option | Stays in place | Holds its shape | Looks right in a room | Lasts |
|---|---|---|---|---|
| Rolled-up towel | No | Flattens quickly | No | Messy, needs resetting |
| Foam strip or door sweep (fitted) | Yes, screwed on | Yes | Hidden | Years, if installed well |
| Light polyester-filled stopper | Mostly | Sags over time | Varies | Short |
| Felted wool draught stopper | Yes, weighted | Yes, dense fill | Yes, in colour | Years |
A fitted door sweep is a good permanent option if you want to fix it to the door and forget it. A weighted stopper needs no installation, and you can move it between doors as the weather changes.
Why wool works well
Felted wool is dense, breathable, and holds its shape for years. It doesn't flatten like foam, hold damp like some synthetics, or carry a chemical smell. That makes it well suited to a job that depends on staying firm and staying put.
Our felted wool draught stopper is filled with flaxseed for weight, with a little dried lavender through the fill. Each one is made by hand in our workroom, in fourteen colours, so the thing blocking your draught doesn't have to be an eyesore.
How to use a draught stopper
- Measure the width of your door at the base. Choose a stopper the same length, or a touch longer, for a clean seal.
- Set it on the warm side of the door, snug against the gap.
- Use the loop at one end to lift it and hang it away when the season turns.
- Try it against a single-glazed window sill, where cold air tends to pool.
- Keep it dry. Spot clean with a damp cloth, and don't soak it.
Other easy ways to stop draughts this winter
The under-door gap is the obvious one, but it isn't the only one. A few low-cost fixes make a noticeable difference:
- Close your curtains before it gets dark to hold heat in the room.
- Add weatherstripping or foam tape around door and window frames.
- Seal small gaps where pipes and wiring pass through walls.
- For single-glazed windows, window film or a secondary-glazing kit cuts a lot of heat loss for little money.
Done together, these take an afternoon, and draught-proofing is one of the cheapest places to start.
Frequently asked questions
Do draught stoppers really work?
Yes, on the gap they cover. They block air moving under a door, which makes a room warmer and steadier almost straight away. The benefit is largest on draughty doors and smaller on doors that are already well sealed.
Where should I put a draught stopper?
On the warm side of the door, pushed against the gap. Use them on exterior doors that open outside, on internal doors to unheated rooms, and along single-glazed window sills where cold air collects.
What is the best filling for a draught stopper?
Something dense and heavy that holds its shape. Natural fills like flaxseed and felted wool stay put, breathe, and don't flatten. Light polyester fills are cheaper but sag over time and leave the gap open again.
Wool or foam, which is better?
Both work. A fitted foam door sweep seals well and stays on the door permanently. A wool draught stopper needs no installation, moves between doors, looks better in a room, and won't carry a synthetic smell. Choose by whether you want permanent or flexible.
Will it fit my door, and can I get a custom length?
Most internal doors are a standard width, so a standard stopper fits. Measure the base of your door to be sure. If your doorway is an odd size, ask us about a custom length before you order.
Do draught stoppers help in summer?
Yes. The same seal that keeps warm air in during winter slows warm air entering a cooled room in summer. Many people leave them in place year-round.
Keep the heat where you want it
A draught stopper won't replace insulation. It will make a room warmer tonight, for very little, with no installation. On a cold winter evening, that is a fair trade. Browse the draught stopper in fourteen colours and pick one to suit the room it sits in.
