Best Draught Proofing for a Sash Window in a Rented Flat

Renters who want to stop a cold sash window leaking air have a narrow set of options: anything fitted must come off again at move-out without damaging paint, frames or glass. This roundup covers the five best draught proofing products for a sash window in a rented flat, from brush pile seals that slide into existing channels to shrink film that turns the whole pane into a sealed barrier. Budget renters, tenants in period conversions with original sashes, and anyone heating a single cold room will each find a match below. The overview table compares every pick first; detailed reviews follow.

The Picks at a Glance

Product	Key Spec	Best Use	Price Tier
Sliding Sash Windows Tape Pile Brush Seal	5mm x 12mm brush pile, 16 ft roll	Sealing the sliding channels of a sash	Budget
XFasten Transparent Window Weather Sealing Tape	2-inch x 30-yard clear tape, no residue	Sealing gaps around a closed sash	Budget
Strong Self-Adhesive Weather Stripping	0.35-inch wide foam strip, 65 ft, 2 pack	Filling wider gaps on frames and sills	Budget
Holikme Draft Blocker 4-Pack	65 ft transparent adhesive strip, 4 rolls	Whole-flat gap coverage, invisible finish	Mid-range
Duck Brand Window Insulation Kit	Shrink film 62 in x 420 in, fits up to 10 windows	Sealing the entire window for winter	Mid-range

Best Overall for Sliding Channels: Sliding Sash Windows Tape Pile Brush Seal

Type: Brush pile seal strip
Profile: 5mm x 12mm
Length: 16 ft (5m)
Color: Gray
Intended Use: Sliding sash window and door channels

16 Ft (5m) 196 Inch Sliding sash Windows Doors Tape Pile Draught excluder Brush Seal Strip weatherstrip 5mm x 12mm (3/16 1/2 Inch, Gray)

This is the pick built specifically for the way a sash window works. The strip is a dense brush pile on a flexible backing, sized to sit in the narrow channel where the sash slides up and down, so the brushes block airflow while still letting the frame move. It suits the vertical runners and the meeting rail of a traditional box sash, and the gray tone blends into most painted frames. Installation is a cut-and-press job along the channel rather than a full dismantle.

It earns its place because it targets the biggest leak on a sash — the sliding gap that foam and tape cannot reach without jamming the window. The catch is that brush pile is a friction fit: a channel that is already tight or full of old paint may need cleaning out first, and the strip will not seal a warped frame or a gap wider than its profile.

Trade-off: The brush seal only works where the channel is clean and correctly sized, so worn or painted-up sashes may need prep before it sits right.

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Best for a Quick, Clean Seal: XFasten Transparent Window Weather Sealing Tape

Type: Clear weather sealing tape
Width: 2 inch (50.8mm)
Length: 30 yards (27.43m)
Finish: Transparent
Adhesive: No-residue claim
Intended Use: Window draft isolation

XFasten Transparent Window Weather Sealing Tape, 2-Inch x 30 Yards (50.8mm x 27.43m), Clear Window Draft Isolation Sealing Film Tape, No Residue

This is the simplest renter-friendly option: a wide clear tape that bridges the gap between the moving sash and the frame, sealing the window shut for the cold months. The transparent finish keeps the glass looking normal from inside and out, and the no-residue claim is the key selling point for anyone worried about the deposit. The 2-inch width covers a decent gap in one pass and the 30-yard roll handles several windows.

It suits tenants who want the job done in minutes and are happy to leave the window closed until spring. The limitation is that sealing the join means the sash can no longer be opened for ventilation, and clear tape on old, dusty or damp frames may not hold as well as it does on clean paint.

Trade-off: Taping the sash shut stops the draught but also stops the window opening, so it is a winter-only fix.

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Best for Wide Gaps and Sills: Strong Self-Adhesive Weather Stripping

Type: Self-adhesive foam weather strip
Width: 0.35 inch
Thickness: 0.2 inch
Length: 65 ft, 2 pack
Color: Gray
Intended Use: Window and door draft sealing, sound and dust reduction

Strong Self-Adhesive, Soundproofing, Draft Blocker, Dustproof, Suitable Doors/Windows Winter 0.35"Wide x 0.2"Thick Grey 65Ft-2 Pack-Weather Stripping Windows Seal Insulation/Doors Draft Stopper

This foam strip is the pick for the places a brush seal cannot reach — the outer frame, the sill line and the meeting rail where the two sashes close against each other. The compressible foam takes up uneven gaps and adds a little sound and dust buffering along with the draught block. Two 65-foot rolls give plenty of spare strip for a whole flat or a second attempt if a run goes on crooked.

It suits renters in older conversions where the frame itself is out of true and simple tape will not bridge the gap. The caution is thickness: 0.2 inch of foam on the sliding face can make a tight sash bind, so it is better used on fixed edges and the closing rail than in the runners themselves.

Trade-off: The foam is thick enough to stop a tight sash sliding freely if it is applied to the moving face rather than the fixed frame.

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Best Invisible Finish: Holikme Draft Blocker 4-Pack

Type: Transparent adhesive draft seal strip
Length: 65 ft
Pack Size: 4 rolls
Finish: Clear
Adhesive: Strong adhesive
Intended Use: Doors, windows and glass panels

Holikme Draft Blocker 4-Pack

The Holikme pack is the tidy option for a renter who wants the draught gone without visible foam or gray brush lines. The strip is clear and adhesive-backed, so it reads as part of the frame rather than an add-on, and four rolls of 65 feet cover a lot of window and door edges. It works on the frame and on glass, which makes it flexible across a flat.

It earns a place for anyone sealing multiple windows or combining window and door draughts in one order. The trade-off is the same as any adhesive strip: it needs a clean, dry, flat surface to stay put, and clear film can lift at the corners over a long, cold winter on a surface that flexes.

Trade-off: The clear strip hides well but relies on a spotless, flat surface, and corners can lift on frames that flex or sweat.

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Best for Whole-Window Sealing: Duck Brand Window Insulation Kit

Type: Shrink film window insulation kit
Film Size: 62 in x 420 in
Coverage: Fits up to 10 windows
Finish: Crystal clear
Included: Window tape
Intended Use: Indoor winter window sealing

Duck Brand Window Insulation Kit, 62 in x 420 in, Fits up to 10 Windows

This is the heaviest-duty answer to a draughty sash: a clear shrink film that is cut to size, taped to the frame and tightened with heat to form an airtight second pane over the whole window. The kit includes its own tape, and the roll is generous enough for a full flat of windows, which makes it good value for a renter sealing a cold property for the season.

It suits tenants who want the maximum draught block and do not need to open the window until spring. The catch is that film covers the whole opening, so the sash cannot be used while it is up, and getting a clean, tight result takes a little patience with the tape and the shrinking.

Trade-off: The film gives the best seal of the five but turns the window into a fixed pane for the winter.

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Before You Buy

• Material: Match the seal to the gap — brush pile for sliding channels, foam for uneven frames, film for a full-window barrier.
• Size: Measure the channel or gap before ordering; a strip that is too thick will bind the sash and one that is too thin will not seal.
• Compatibility: Check that the sash still needs to open. Anything taped or filmed shut is a winter-only fix.
• Rental safety: Favor peel-clean tapes and films with a no-residue claim, and test a small patch on old paint before a full run.
• Surface prep: Clean and dry the frame first; dust, damp and flaking paint are the main reasons adhesive seals fail.
• Care: Wipe brush pile and foam clean rather than soaking them, and remove film and tape gently at the end of the season.
• Included accessories: Kits that bundle tape save a second order, and spare strip is worth having for a second attempt.

Frequently Asked Questions

1. Can a renter draught proof a sash window without damaging it?
   Yes. Peel-clean tapes, brush pile in the existing channels and shrink film all come off at the end of the season, provided the frame is prepared and the tape is removed slowly.

2. What is the best draught proofing for a sash window in a rented flat overall?
   Brush pile in the sliding channels seals the biggest leak without stopping the window working; clear tape or film is the better choice when the window can stay shut for winter.

3. Will draught proofing stop a sash window opening?
   Only if it seals the moving join. Brush pile and foam on fixed edges keep the sash usable; tape over the join and shrink film both lock the window closed.

4. How much strip is needed for one sash window?
   Measure the full perimeter of the frame and the sliding channel, then add a little spare. A 16 ft roll covers a single window; multi-roll packs suit a whole flat.

5. Does draught proofing help with noise as well as cold?
   A little. Foam and brush pile buffer some sound and dust along with the draught, but a full acoustic fix needs more than a seal strip.

6. When should the draught proofing come off?
   Remove film and tape in spring, before warm weather, so the window can open again and the adhesive does not bake onto the frame.

Bottom Line

For most renters, the Sliding Sash Windows Tape Pile Brush Seal is the best draught proofing for a sash window in a rented flat: it targets the sliding channel that actually leaks, keeps the window working, and comes off without a trace. Tenants who can leave the window shut for the season should pair it with the Duck Brand film kit for a full barrier.

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