02 / WINDOWS
The best window draft stoppers, and when to buy something else
Most people searching for this want a fabric tube for the sill. Sometimes that is right. Often the cheaper, permanent fix is a strip of weatherstrip in the sash gap — so this page covers both.
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If your sash rattles, buy weatherstrip for the gap — it seals, it costs a few dollars, and it works with the window shut or open. Buy a laid draft stopper only for a window that is staying shut all winter. A tube on the sill blocks bulk air; it cannot seal a gap the way a compressed strip does.
Two different products, one search term
Search for a window draft stopper and you will be shown fabric tubes. Some of them are good. But a large share of the people typing that phrase have a sash that does not close tightly against its frame, and for them a tube on the sill is treating the symptom while the hole stays open.
The distinction is simple once you see it. A laid stopper sits against the opening under its own weight. Nothing holds it there and nothing compresses it, so it slows the air moving across the sill without closing the path. A weatherstrip is pushed or stuck into the gap itself, and when the window closes it is squeezed between two surfaces. That squeeze is what makes a seal.
Both are on this page, because both are legitimate. What we will not do is let the more photogenic product take credit for the other one's job.
Match the part to your gap
Measure at the widest point. Then read across. If your measurement sits on a boundary, take the larger band — a seal that is slightly too big compresses, and one that is too small does nothing at all.
| Your gap | Part type | Our pick | Price |
|---|---|---|---|
| Sash rattles in its frame | T-profile sash weatherstrip |  Kneelisa T-Shape Sash Window Weather Stripping, 118 inSeals the gap instead of covering it. The right answer for most people who searched for a draft stopper. | $8.99 · CHECK ON AMAZON |
| Cold sill, window staying shut | Laid draft snake, window-rated |  FILTERWOW Draft Stopper for Door Bottoms and Window SillsThe maker names window sills specifically rather than selling a door part and hoping. | $13.95 · CHECK ON AMAZON |
| Exposed sill, tube gets blown aside | Weighted laid stopper |  KAKICLAY Weighted Draft Stopper for Doors and Windows, 36 in, 2.2 lbPublishes a 2.2 lb weight. Weight is the only meaningful spec on a laid seal. | $16.99 · CHECK ON AMAZON |
| Gaps you cannot fit a strip into | Rope caulk |  Frost King B2 Mortite Fingertip Caulking Cord, 1/8 in x 90 ftPressed into an irregular gap and peeled off in spring. The renter's answer and often the best one. | $6.67 · CHECK ON AMAZON |
What weight actually buys you
Among laid stoppers, weight is the one specification worth paying attention to, and almost the only one anybody publishes. A light fabric tube on an exposed sill gets pushed aside by the very draft it was bought to stop — not dramatically, just a half-inch over a few hours, which is enough to open the path again.
One of our picks publishes 2.2 lb for a 36 in tube. That is heavy enough to stay put in a gusty room and heavy enough to be a genuine nuisance to lift off a sill twice a day. Which of those matters more depends entirely on whether the window opens, which is why the honest recommendation changes with the room.
The renter's case for rope caulk
Rope caulk deserves a mention here because it solves the problem that defeats both other categories: a gap that is not a consistent shape. Old sashes are not straight, and a strip of weatherstrip bridges a warped gap at its widest point and stands off it everywhere else.
Rope caulk is a non-hardening putty rope pressed into the gap with a thumb. It takes the shape of whatever it meets, it seals genuinely well, it costs very little for ninety feet, and it peels off in spring without residue. It is on this page rather than buried in rope caulk vs V-seal vs film because for a rented flat with rattly sashes it is frequently the correct answer and almost nobody suggests it.
The catch, and it is a real one: the window is sealed shut until you remove it. On a bedroom window that is a fire-safety decision, not a comfort one. Make it deliberately.
The picks
Quick picks
Ranked for fit, not for hype. Tap a row to jump to the full write-up, or go straight to the listing.
| # | Product | Best for | Gap range | Price |
|---|---|---|---|---|
| 1 | Kneelisa T-Shape Sash Window Weather Stripping, 118 inThe pick for people who arrived looking for a window draft stopper and actually need weatherstrip — a T-profile strip made for the sash gap itself. | Sealing the sash instead of covering it | Not published as a range; a T-profile sized to a sash channel | $8.99 · CHECK ON AMAZON |
| 2 | FILTERWOW Draft Stopper for Door Bottoms and Window SillsOne of the few draft snakes whose maker actually names window sills as a use rather than leaving you to assume it, which is the difference between a door product and a window product. | A window sill you can lay a tube along | Not published — a laid tube conforms to whatever gap it covers | $13.95 · CHECK ON AMAZON |
| 3 | KAKICLAY Weighted Draft Stopper for Doors and Windows, 36 in, 2.2 lbThe heavy one — a published 2.2 lb means it stays where you put it when the wind gusts, which is the failure mode of every light fabric tube. | A sill in a windy spot | Not published — a laid seal, weighted rather than fitted | $16.99 · CHECK ON AMAZON |
| 4 |  Frost King DS2 Door or Window Draft Stop Cloth Seal, 3 ftFrost King publishes this one for windows as well as doors, which puts a real weatherseal brand behind a category otherwise full of unbranded fabric tubes. | A named window part from an established maker | Not published; Frost King publishes a 3 ft length | $22.26 · CHECK ON AMAZON |
| 5 | Frost King B2 Mortite Fingertip Caulking Cord, 1/8 in x 90 ftRope caulk: pliable putty you press into a gap in October and peel out in April, leaving no adhesive behind. | Seasonal window sealing | Published 1/8 in cord; fills gaps of roughly 1/16 in to 1/4 in when pressed | $6.67 · CHECK ON AMAZON |
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Sealing the sash instead of covering it
Kneelisa T-Shape Sash Window Weather Stripping, 118 in
Published gap range
Not published as a range; a T-profile sized to a sash channel
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The pick for people who arrived looking for a window draft stopper and actually need weatherstrip — a T-profile strip made for the sash gap itself.
Where the number comes fromA T-profile pushes into the gap between the sash and the frame rather than lying on the sill. That makes it a genuine seal instead of a windbreak, but it only works if there is a channel or a consistent gap to push it into. The listing publishes a 118 in length and the T shape; it publishes no working gap range, so test the fit on a short offcut before committing the whole roll.
- Published length
- 118 in
- Profile
- T-section
- Built for
- Sash windows
- Fitting
- Self-adhesive
- Published gap range
- None
- Mounting
- Pressed into the sash-to-frame gap, self-adhesive backing
What it does well
- Actually seals the sash gap rather than covering the sill below it
- 118 in does a whole double-hung window with margin
- Cheapest real fix on this page per window
Where it fails
- Only works where there is a consistent gap for the T to seat in — a warped sash defeats it
- The window has to stay shut; this is not a strip you fit and then open daily
- No published gap range, so the fit is trial-and-error on the first foot
Who this is forAn old double-hung whose sash rattles in its frame.
A window sill you can lay a tube along
FILTERWOW Draft Stopper for Door Bottoms and Window Sills
Published gap range
Not published — a laid tube conforms to whatever gap it covers
#ad · how we are funded · price as of October 17, 2026
One of the few draft snakes whose maker actually names window sills as a use rather than leaving you to assume it, which is the difference between a door product and a window product.
Where the number comes fromNothing in this category publishes a working gap range, and the honest reason is that a laid tube does not have one: it rests against the opening and blocks bulk airflow rather than compressing into a measured gap. That makes it a good fix for a leaky sash meeting rail or a cold sill, and a poor substitute for weatherstrip where the two surfaces actually close against each other.
- Published use
- Door bottoms AND window sills
- Fitting
- Laid in place, no adhesive
- Removable
- Completely
- Published gap range
- None
- Reusable
- Yes — lift and re-lay
- Mounting
- Laid along the sill or the bottom of the sash; nothing is fixed
What it does well
- The maker names window sills specifically, rather than selling a door part and hoping
- No adhesive, no fixings, nothing to damage a rented window
- Lifts out in a second when you want the window open
Where it fails
- A laid tube slows bulk air; it cannot seal a gap the way compressed weatherstrip does
- Has to be moved every time you open the window, which is why people stop using them
- No published dimensions on the listing beyond the product form
Who this is forA window that is staying shut all winter and a sill that is visibly cold.
A sill in a windy spot
KAKICLAY Weighted Draft Stopper for Doors and Windows, 36 in, 2.2 lb
Published gap range
Not published — a laid seal, weighted rather than fitted
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The heavy one — a published 2.2 lb means it stays where you put it when the wind gusts, which is the failure mode of every light fabric tube.
Where the number comes fromThe listing publishes a 36 in length and a 2.2 lb weight, and names both doors and windows. Weight is the only meaningful spec on a laid draft stopper: it is what keeps the tube against the opening instead of being pushed aside by the very draft you are trying to stop. No gap range is published.
- Published length
- 36 in
- Published weight
- 2.2 lb
- Published use
- Doors and windows
- Fitting
- Laid, not fixed
- Published gap range
- None
- Mounting
- Laid against the sill or door bottom
What it does well
- A published weight, which almost nothing else in this category states
- Heavy enough to hold position against a real draft
- 36 in covers a standard sash or a door bottom
Where it fails
- 2.2 lb on a window sill is a lot to lift off every time you open it
- Still a laid seal — bulk airflow only
- The listing leans on noise-reduction language that names no test we can check
Who this is forAn exposed sill where a lighter tube has already been blown out of place.
A named window part from an established maker
Frost King DS2 Door or Window Draft Stop Cloth Seal, 3 ft
Published gap range
Not published; Frost King publishes a 3 ft length
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Frost King publishes this one for windows as well as doors, which puts a real weatherseal brand behind a category otherwise full of unbranded fabric tubes.
Where the number comes fromFrost King publishes the DS2 as a 3 ft cloth draft stop for a door OR a window. Three feet is the figure to check against your sash width — a typical double-hung is close to that, a picture window is not. No working gap range is published, which is standard for a laid seal.
- Published length
- 3 ft
- Published use
- Door or window
- Maker
- Frost King (Thermwell)
- Pack
- Sold as a pack of 12
- Published gap range
- None
- Mounting
- Laid along the sill or door bottom
What it does well
- An established weatherseal maker rather than an anonymous reseller
- Published explicitly for windows, not just adapted to them
- 3 ft suits a standard double-hung sash without trimming
Where it fails
- **Sold by the case.** The listing we verified is a pack of twelve, so the price shown covers twelve pieces, not one — right for a whole house, absurd for a single window
- Same limitation as every laid seal: it blocks bulk air, it does not close a gap
- 3 ft is short for a wide window and cannot be joined neatly
Who this is forA house with a lot of cold sills and a willingness to buy in bulk.
Seasonal window sealing
Frost King B2 Mortite Fingertip Caulking Cord, 1/8 in x 90 ft
Published gap range
Published 1/8 in cord; fills gaps of roughly 1/16 in to 1/4 in when pressed
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Rope caulk: pliable putty you press into a gap in October and peel out in April, leaving no adhesive behind.
Where the number comes fromFrost King publishes the cord diameter (1/8") and length (90 ft). Rope caulk deforms into the gap, so one cord covers a range — press two strands together for a wider gap.
- Published diameter
- 1/8 in
- Published length
- 90 ft
- Removal
- Peels out, no residue when fresh
- Tools
- None — fingertip pressure
- Color
- Gray
- Mounting
- Pressed in by hand, no tools
What it does well
- Genuinely removable, which is why renters and old-window owners keep buying it
- No adhesive to fail and no surface prep beyond wiping dust off
- 90 ft does a lot of window
Where it fails
- Left in through summer heat it gets harder to remove cleanly
- Seals a window shut — no ventilation until you pull it
- Looks like what it is: putty in a gap
Who this is forOld double-hung windows you want sealed for winter and openable in spring.
What we would skip, and why
Nobody in this category ever declines to recommend something. That is what makes universal praise worth ignoring. Here is what we would not buy.
A draft stopper on a window you need to open
This sounds obvious and it is the single biggest reason these products end up in a drawer by February. A laid tube has to be lifted off and put back every time the window is used, and a weighted one is genuinely heavy. If the window is a fire escape route, a bathroom vent or the one you open to cool the kitchen, buy weatherstrip that stays in the gap instead — it works whether the window is shut or not.
Expecting a laid tube to seal like weatherstrip
A tube resting on a sill blocks bulk airflow. It does not seal, because there is nothing compressing it against a mating surface — it is a windbreak, not a gasket. On a genuinely leaky sash it will reduce the draft you feel at ankle height and leave the air path itself open. That is a real improvement and it is not the same thing as sealing the window, and no listing in this category is straight about the difference.
Buying the case pack for one cold window
Two of the better-known products in this category are sold in multipacks — one of our picks is a pack of twelve. For a whole house of cold sills that is good value. For the single bedroom window that woke you up at 3am it is eleven pieces of wasted money. Check the pack quantity before you check the price, because the price shown is for the pack.
A draft stopper where the real leak is the frame
Old windows leak at the sash, but they also leak where the frame meets the wall — behind the architrave, where nothing you lay on the sill can reach. A smoke pencil or a damp hand on a windy day will tell you which within a minute. If it is the frame, the fix is caulk and backer rod, and it is permanent.
How we picked
- We start by splitting the category, because the search term hides two different products. A laid draft stopper is a tube you rest against the opening. Sash weatherstrip is a strip that lives in the gap. Both are bought by people typing the same words, and they behave completely differently.
- For laid stoppers we rank on the two things a maker can honestly publish: whether the product is rated for windows at all rather than adapted from a door part, and its weight, which is what stops the draft pushing it aside.
- For weatherstrip we rank on published profile and length, and we say plainly when a listing publishes no working gap range — which is most of them.
- Nothing here is tested by us. No lab, no inventory, no credentials — the full method says so and explains what we do instead.
We have not tested these products and we do not claim to have. The full method, including what we refuse to claim, is on how we pick.
Complete the kit
The parts that decide whether the seal you just bought actually holds. Skip these and you will be doing the job again in March.
Removing old weatherstrip adhesive
Goo Gone Pro-Power Adhesive Remover Spray, 16 fl oz, with Scraper
The step everybody skips: the new tape will not stick to the residue the old tape left behind.
Deep gaps before caulking
Frost King C21CP-C Caulk Saver Backer Rod, 3/8 in x 350 ft
Backer rod: the foam you push into a deep gap so the caulk over it is a seal rather than a bottomless hole.
Trying it on one room
3M Indoor Window Insulator Kit, Two Pack
The two-window box: the right way to find out whether film solves your problem before committing a whole house to it.
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When the answer is film, not a stopper
If the sash is sound, the frame is sealed and the room is still cold near the window, what you are feeling is very likely not infiltration at all. Cold glass chills the air touching it, that air gets denser and falls, and it runs across the floor. It feels identical to a draft and there is no hole to find.
Nothing on this page fixes that. Shrink film does, by putting a still air layer in front of the glass, and it is the one product in this category whose mechanism we can explain without hand-waving. We also wrote about whether it is worth it at all in does window film actually work, including the situations where the answer is no.
Questions people actually ask
- Do window draft stoppers actually work?
- A laid tube reduces the draft you feel across the sill, which is a genuine comfort improvement. It does not seal the air path, because nothing compresses it against a mating surface. If your sash has play in it when locked, weatherstrip or rope caulk in the gap will do more, cost less, and keep working when the window is open.
- What is the difference between a draft stopper and weather stripping?
- A draft stopper is laid against the opening and held by its own weight. Weatherstrip sits inside the gap and is compressed when the window closes. Compression is what makes a seal, which is why weatherstrip closes an air path and a laid tube only slows the air moving past it.
- Can I use a door draft stopper on a window?
- Often yes, if the length suits the sill, and several products are sold for both. What to check is whether the maker actually publishes window use — some are door products with a window photo. The bigger question is the same either way: is your problem a gap to be sealed, or cold air spilling off the glass?
- Will a draft stopper stop condensation on my windows?
- No, and it may slightly increase it. Condensation forms when humid room air meets cold glass. Blocking a draft does not warm the glass, and reducing air movement at the sill can leave more moisture sitting there. Warming the glass with film or reducing indoor humidity are the levers that actually move that problem.
Read next
The best weather stripping tape for windows
Tape, V-strip and rope caulk placed by gap and by where on the window they can survive.
Rope caulk, V-seal or film: three ways to seal a window
Three ways to seal a window, decided by one question: does it still have to open?
The best window insulation kits, by published coverage
Shrink-film kits ranked by published coverage and film weight, plus the frame checks that decide whether the tape holds.
Draft fixes for renters that leave no trace
Rope caulk, stoppers and removable film — the fixes that come out clean at move-out.