Reducing Draughts in Old Windows and Doors

Why Old Windows Feel Cold — And Why That's Not Always a Fault

If you live in a period moorland property, you'll know the feeling: a fire roaring in the grate, a thick rug underfoot, and yet a persistent chill curling around your ankles from the window seat. Original sash windows and panelled doors were never designed to be airtight. They were built to move, to settle, and to let a little air pass through so that timber could dry out and damp wouldn't take hold behind the paint. Sealing them up completely with modern foam and silicone is the surest way to end up with rotten sills and swollen frames.

The trick is to slow the air down without stopping the joinery from breathing. Fortunately, there's a whole family of discreet measures — brushes, seals, beading and heavyweight textiles — that do exactly that, and most are reversible if you ever need to take them out.

Draught-Proofing Sash Windows Without Locking Them Shut

Vertical sliding sashes are the biggest culprits in a stone cottage or Georgian farmhouse. Cold air sneaks in around three places: the meeting rail where the two sashes overlap, the sides where they run in their grooves, and the gap under the bottom rail.

Start with the meeting rail. A self-adhesive brush seal fitted to the inner face of the top sash's lower rail will close that gap while still allowing the sashes to slide past one another. Look for brush pile with a fin, roughly 5–7mm deep, and choose a colour that matches your paintwork so it disappears into the shadow line.

For the sides, carrier or parting-bead brushes are the neatest option. These sit inside the existing groove, held in place by the bead itself, and are fitted during a strip-down and re-cord rather than as a quick fix. If you're not taking the window apart, a slim brush strip pushed into the gap will make a measurable difference.

• Fit brushes to the meeting rail first — it's the single largest source of draught.
• Check whether the sashes rattle. A rattle means a worn bead, and no amount of sealant will fix it.
• Add a sash lift or fitch catch to pull the sashes together tightly when closed.
• Leave the pulley wheels and cords alone — never pack them with sealant, as moisture needs to escape.

Doors: Thresholds, Letterboxes and the Gap You Can't See

Old panelled doors rarely sit flat in their frames. A gap of 4mm along the hinge side can let through as much cold air as a small open window. Before you buy anything, do the candle test on a windy evening — pass a lit tea light slowly around the door's perimeter and watch where it flickers. It's a crude method, but it's honest, and it tells you exactly where to spend your effort.

For the hinge and lock sides, a carrier-style brush seal screwed into the frame rebate is more durable than self-adhesive foam, which crushes flat within a season and then peels. For the top and bottom, a compression seal — the sort with a hollow rubber bulb in a rigid carrier — will hold its shape far better.

At the threshold, thin brush strips work well over flagstones and slate, and they cope with the slight unevenness that comes with an old floor. If your door has a letterbox, a brush-lined internal flap on the inside face is the single most effective thing you can do for a draughty hall; the outer flap alone rarely seals properly.

Heavy Curtains Do More Than You'd Think

Textiles are the traditional answer, and they still work. An interlined wool curtain hung on a proper track, with the leading edges overlapping by 5–10cm at the centre, will cut perceived draughts dramatically. The trick is to hang it close to the wall, with returns at each side, so cold air is trapped behind rather than spilling around the edges into the room.

Curtains should reach the floor — or, better, sit on a sill-height pelmet that hides the track entirely. A pelmet isn't just decorative; it stops warm air from rising into the box and drawing cold air down the glass. In a stone cottage with deep reveals, fix the track inside the reveal where you can, and let the fabric pool slightly against the wall. The heavier the fabric, the more it will deaden sound from outside too, which matters if you're near a lane or open moorland wind.

Making the Most of Shutters, Blinds and Secondary Glazing

If your property still has its original timber shutters, use them. Closed internal shutters create a still air pocket between glass and panel that's worth more than any seal. Where the shutter leaves have shrunk and no longer meet, a slim brush strip or a strip of self-adhesive felt along the closing stile will restore the seal.

Secondary glazing is the quiet hero here. A slim, clear acrylic or glass panel fitted inside the reveal with magnetic or brushed seals can reduce heat loss substantially, and it's fully removable for cleaning and summer ventilation. It also leaves the original window untouched — essential in a listed building, and simply good practice in any period home.

• Choose a secondary panel that's easy to lift out; you'll want the window open on warm days.
• Never seal a window so tightly that condensation forms on the inner face of the glass.
• Roman or roller blinds hung close to the glass help, but avoid linings that trap damp against the frame.

Keeping Timber Healthy While You Keep Warm

Every seal you fit should be a draught seal, not a vapour barrier. Paint is the real enemy of breathability: thick modern gloss on an external face traps moisture in the wood, which then blows the paint and softens the timber from behind. Stick to breathable finishes — linseed oil paint, microporous stains — on external joinery, and let the seals do the work of keeping warm air in.

Check your seals each autumn. Brush pile flattens, rubber hardens, and self-adhesive strips give up. A half-hour of inspection and a handful of replacement lengths will keep a moorland home noticeably warmer all winter, and your original joinery in fine fettle for another century of wind and weather.