How to Find and Stop Window and Door Draughts Before Winter

Stopping a draught is the easiest way to prepare your home for the winter chills, and the one most people put off every year. A seal that has hardened or shrunk allows cold air to seep in, and because it happens gradually, there is rarely a moment when you notice it has gone. Instead, you’ll see your heating bills creep up every year as your home becomes less efficient.

Autumn is the perfect time to check, while the weather is still mild enough to have a window repaired for ten minutes. Here's how to find a draught, work out what is causing it, and put it right before the cold sets in.

Why draughts show up in autumn

Rubber gaskets move with the weather. Like the rest of your home, you will find expansion and contraction as the mercury rises and falls. 

Through summer, they sit warm and relaxed. As temperatures drop, they stiffen and contract, and eventually crack and break.

That is also why seals tend to pull back from the corners first. Each winter the material shrinks a little, and over several seasons it does not fully recover. If you can see a gap at the top corners of a window, the seal has reached the end of its working life.

Four ways to find a draught

1. The paper test. Close a sheet of paper in the window or door, then pull. If it slides out freely at one point but grips elsewhere, the seal is not meeting the frame at that spot.
2. The hand test. On a cold, windy day, run the back of your hand slowly around the opening edge. This is useful for finding the bigger gaps quickly.
3. Look at the corners. Gaps where the seal has shrunk back are visible with the window open, and they are the most common failure point.
4. Press the rubber. A healthy gasket springs back. One that stays squashed, or feels hard and brittle, has flattened and will not seal under compression.

Where the draught is tells you what to fix

This part saves a lot of wasted effort, particularly on doors.

A draught along the opening edge of a window. The frame gasket has gone. Replace the seal, and our Seal Centre will help you identify the profile.

A draught on the hinge side of a door. Either the gasket or hinge compression. Adjusting the hinges pulls that edge tighter against the seal, and our guide on how to adjust uPVC door hinges covers it.

A draught on the lock side of a door. Not the hinges, and often not the seal either. That edge is pulled in by the multipoint locking points meeting their keeps, so the keeps are what need looking at.

A draught around the glass rather than the opening. The glazing seal, which is a wedge gasket rather than a frame gasket.

When it is the seal, and when it isn't

Not every cold window is a failed gasket. A single-glazed or older double-glazed unit will always feel cooler than a modern one, and cold radiating off glass is not the same as air moving past a seal. Our guide on window sealant or window seal explains which is which.

Your autumn draught check

1. Work round the house one window at a time, with the paper test.
2. Note which openings fail, and whether the gap is along the opening edge or at the corners.
3. Check the doors separately, and note which edge the draught is on.
4. Measure the openings that need doing, adding all four sides of each sash together.
5. Identify the profile before you order. Our Seal Centre walks through it, and a sample pack is the surest way if you are not certain.

Shop replacement seals with GB DIY

Replacing a seal is one of the cheapest jobs in the house, and one of the few that pays you back every day of the winter. Browse window and door seals for bubble, flipper and wedge gaskets, cut by the metre in black or white, with same-day dispatch before 3pm.

Not sure which profile you need? Send us a photograph with a tape measure next to it, or get in touch here, and we will identify it for you.

Window draught FAQs

How do I know if my window seals need replacing?

Close a sheet of paper in the window and pull it out. If it slides free with no resistance, the seal is not meeting the frame there. Look too for rubber that has gone hard, flattened, or shrunk back from the corners. Any of those means the gasket has reached the end of its life.

Can I stop a draught without replacing the seal?

Sometimes. On a door, adjusting the hinge compression pulls the hinge edge tighter against the seal, which can be enough if the gasket is still supple. If the rubber has hardened or flattened, adjustment will not bring it back and the seal needs replacing.

When is the best time to replace window seals?

Early autumn. The rubber is still warm and flexible, which makes it easier to fit, and you are doing the job before the weather makes an open window unwelcome.

Will new seals reduce my heating bills?

They will stop cold air coming in and warm air escaping around the openings, which makes rooms noticeably more comfortable. How much that saves depends on how bad the seals were and how you heat the house, so treat it as a comfort fix first.