Why Old Windows and Doors Are Worth Keeping

There is something deeply comforting about an old house in winter: thick walls, low beams, and the smell of woodsmoke drifting from the grate. But that same character comes with a catch. Sash windows that have settled over a century, timber doors that have swollen and shrunk with every season, and a letterbox that seems to whistle in the wind can let in more cold air than you would believe. A single draughty gap the width of a two-pound coin can feel like leaving a small window open all day.

The good news is that you do not need to rip out your period joinery or spend a fortune on replacements. With a few inexpensive materials and an afternoon's work, you can make old windows and doors noticeably warmer, quieter, and kinder to your heating bill — without losing the charm that made you fall in love with the place.

Start by Finding the Draughts

Before you buy a single strip of foam, work out where the cold air is actually getting in. On a windy day, hold a lit candle or a thin strip of tissue near the edges of each window and door. Watch where it flickers. You will usually find draughts in four predictable places:

• Around the frame, where the timber meets the masonry or plaster.
• Between the sash and the frame on older windows, especially along the meeting rail where the two sashes overlap.
• Under the door, where a gap of a few millimetres is normal and often overlooked.
• Through the letterbox, which funnels cold air straight down the hallway.

Make a note of each spot. It is far easier to fix them methodically than to guess and end up with a half-finished job by teatime.

Draught-Proofing Old Windows

Original sash windows deserve care. They were built to last, and a little maintenance will keep them working smoothly for decades. Start by cleaning the frame and the channels the sashes slide in, then check that the sash cords and pulleys are sound. A window that rattles will never seal properly.

For gaps between the moving sashes and the frame, self-adhesive foam or rubber draught excluder is the simplest fix. Choose a slim profile — around 6mm — so the window still closes without straining. Press it into the rebate where the sash meets the frame, trimming with scissors at the corners. For the meeting rail in the middle, where the two sashes overlap, a brush or wiper seal works better than foam because it does not stop the sashes sliding past each other.

Sash windows also have a nasty habit of letting air in around the pulley wheels at the top. A small square of foam pushed behind the pocket piece will sort that quietly. If your window has a permanent gap between the frame and the wall, fill it with flexible acrylic sealant rather than cement, which cracks as the house moves. Press it in with a finger dipped in washing-up liquid for a neat finish.

Finally, a heavy pair of thermal curtains or a Roman blind hung close to the window makes a real difference on the coldest nights. Close them at dusk and the room will hold its warmth far longer.

Sealing Doors and Frames

Doors are usually the biggest offender. An external door that has swollen in the damp can have gaps at the top and bottom all at once. Begin by checking the hinges and latch — a door that does not sit square will never seal, no matter how much excluder you fit.

For gaps down the sides and across the top, a brush or rubber seal fixed to the door stop is the neatest option. These press against the door as it closes and last far longer than foam in a doorway, which gets kicked and caught. For the base of the door, fit a brush draught excluder or a screw-on aluminium carrier with a rubber strip. Measure the width carefully and cut slightly long, then trim to fit once the door swings freely.

If the gap under the door is more than about 10mm, consider a retractable automatic door seal that lifts when the door opens and drops as it closes. It is a little more expensive, but it seals beautifully and does not scrape along a stone threshold. Around the frame itself, run a bead of acrylic sealant where the architrave meets the wall, and remember to do the same on internal doors that adjoin cold hallways or unheated rooms.

Don't Forget the Letterbox

The letterbox is the sneakiest draught in the house. It sits low on the door, so cold air pours straight into the hallway and pools around your feet. Fitting a letterbox flap with a brush or rubber seal on the inside makes an immediate difference. Most are screwed to the inside face of the door in minutes, and many come with a draught-proof brush already attached.

If you already have an internal flap, check that it closes fully against the door. A small self-adhesive rubber strip along its edge will often be all it needs. For a belt-and-braces approach, a fabric draught excluder hung behind the letterbox will catch anything the flap misses.

Keep It Breathable, Keep It Cosy

One word of caution from someone who has seen the damage a sealed-up cottage can suffer: old houses need to breathe. Blocking every vent and sealing every crack can lead to condensation, damp patches, and black mould on cold walls. Fix the obvious draughts, but leave air bricks and trickle vents alone — they are there for a reason.

Work through your windows and doors one room at a time, testing each seal as you go. A well-fitted draught excluder should be invisible, silent, and lasting. Do that, and you will spend the rest of winter with the fire lit, the kettle on, and not a whisper of cold air sneaking under the door.