The Best Door Draft Stoppers and Window Insulation: 4 Compared (and One to Skip)

RBE top pick

Frost King Premium Aluminum and Reinforced Rubber Door Sweep

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The Frost King sweep fixes the door gap properly and carries a lifetime guarantee on the rubber. The Duck kit handles the window side of winter heat loss for very little effort.

Winter heat loss around doors and windows comes down to a few cheap parts, and most of the choice is picking the right type for the gap you have. The field splits into screw-on sweeps, stick-on sweeps, fabric snakes that sit on the floor, and shrink film for windows. We checked four current models from Frost King, Duck and M-D Building Products against the makers' own pages. Two are easy picks, one depends on your door, and one is a popular type we would pass on. Pair this with our guides on space heaters, electric blankets and humidifiers if you are sorting out a cold room.

RBE top pick

Frost King

Frost King Premium Aluminum and Reinforced Rubber Door Sweep (A79/36A)

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Buy it

A screw-on aluminum and rubber sweep with a lifetime guarantee on its weathersealing, and the one to get for an exterior door.

Best for: Anyone with a drafty exterior door who is willing to drill once.

$ · mid-range

Why we like it

• The rubber sweep is reinforced and the maker guarantees it will keep its weathersealing ability for life.
• It is a rigid, screw-mounted profile that stays put when the door swings, unlike a stick-on strip.
• The 2 inch by 36 inch size covers a standard door width and comes in silver, white, gold and satin nickel finishes.

Know before buying

• It needs a drill and 1/8 inch bit, so it is more work than a peel-and-stick strip.
• The maker page gives no product-specific install steps, so you rely on the instruction PDF.
• A sweep that is mounted too low can drag on carpet or rub the threshold.

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Duck

Duck Brand Rolled Shrink Film Window Insulation Kit, 62 in. x 210 in. (5 windows)

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Buy it

The cheapest way to stop a drafty window from leaking heat for the winter, with a roll format that needs no measuring.

Best for: Renters and anyone with older single-pane or leaky windows who wants a cheap winter fix.

$ · budget

Why we like it

• One roll of crystal clear shrink film plus window kit tape is listed as covering 5 windows.
• No measuring is required because you apply the film and cut off the excess afterward.
• The maker says it removes cleanly from painted or finished wood, aluminum or vinyl, which suits renters.

Know before buying

• It is a seasonal fix: the film comes off in spring.
• The page warns it is not safe for plaster, drywall, wallboard or unfinished wood surfaces.
• You need a hair dryer and scissors, and a poor tape seal on a dusty frame will let the film sag.

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M-D Building Products

M-D Building Products Aluminum and Vinyl CINCH Self-Adhesive Door Sweep (43301)

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It depends

A stick-on sweep with a triple-fin vinyl seal that suits flat thresholds and renters, and is only as good as the surface it sticks to.

Best for: Renters or anyone who cannot drill into the door and has a clean, flat door bottom.

$ · mid-range

Why we like it

• It uses a 3M adhesive and needs no hardware, so you cut it to length and stick it to the door.
• The maker lists it as sealing gaps up to 1 inch with a triple-fin vinyl seal.
• It comes in white, bronze, silver and black, so it can match a door finish.

Know before buying

• Adhesive hold depends on a clean, flat door bottom, and a flexing or textured door may let it peel.
• It seals against the side of the threshold, so it suits some door setups better than others.
• The maker page lists no warranty and no reviews.

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We'd skip it

Frost King

Frost King Door or Window Double Draft Stop (DDS1)

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Skip it

A fabric-covered foam snake that slides on under a door, with a maker page that says little about what it is made of or how much it helps.

Best for: A door you rarely open, such as a spare room or storage door, where a quick temporary block is enough.

$ · budget

Why we like it

• It needs no tools: you slide it under the door, or close a window on it.
• The foam tubes can be cut and the ends folded over to fit narrower doors and smaller windows.
• It is 1-1/4 inches wide and up to 36 inches long, which covers a standard door.

Know before buying

• The maker page does not state the cover material and only mentions foam tubes in its FAQ.
• The claims are general (blocks drafts and dust, reduces energy loss) with no figures or test method behind them.
• The maker states it is not rigid enough to stop all bugs from crawling under a door.
• It sits loose on the floor and shifts when the door is used, so it is a fix you have to reposition.

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How we judged the field

Five things matter with draft stoppers. Type decides whether the gap is actually closed: a sweep is fixed to the door, a snake is loose on the floor, and film covers a window. Adjustable height and cut-to-length matter because doors and thresholds vary. Install method decides whether you will do it right, whether that means drilling, sticking, or taping. Material decides durability, and a maker that does not name the material gives you less to go on. Finally, the maker’s stated size range tells you whether it will fit your door or window before you buy.

The field splits into rigid sweeps, stick-on sweeps, fabric snakes and window film. We picked one of each from makers whose own pages gave sizes and install details. Frost King covers the screw-on sweep and the snake, Duck covers window film, and M-D covers the stick-on option. We kept the snake as the skip because it is the most commonly bought type and the least documented. For heating the room itself, see our space heater and electric blanket reviews, and for dry winter air see the humidifier review.

The Frost King A79 is the one we would buy first for an exterior door. It is a 2 inch by 36 inch aluminum profile with a reinforced rubber sweep along the bottom, and it screws to the door. That gives it a rigid, fixed position, which matters because a sweep has to touch the threshold every time the door closes. The maker backs the rubber with a lifetime guarantee that it will keep its weathersealing ability, though the page does not spell out the terms. Frost King’s general advice is to mount most sweeps on the inside of an in-swinging door and to use a 1/8 inch drill bit for pilot holes. The trade-off is effort. You need to check that 36 inches suits your door width, drill, and set the height so the rubber touches the threshold without dragging. If your door has a gap you can see light through, this is the fix that lasts. It is for homeowners who would rather do the job once.

Door gaps are only part of winter heat loss, and old windows are the other. The Duck rolled shrink film kit is the budget answer. One roll of clear shrink film comes with window kit tape and is listed as covering five windows at 62 inches by 210 inches total. The roll format means you do not measure each window: you apply the film and trim the extra afterward, then use a hair dryer to tighten it. The maker says it removes cleanly from painted or finished wood, aluminum and vinyl, but warns that it is not safe for plaster, drywall, wallboard or unfinished wood. The page also says savings of up to 10 percent on energy costs depend on a home that is properly sealed and insulated, and that this is an estimate. Treat that as a ceiling. It is a one-season product, because you take it down in spring. It suits renters and anyone with leaky windows that cannot be replaced.

The M-D CINCH is a self-adhesive sweep for people who cannot or will not drill. It is a 36 inch by 2 inch aluminum and vinyl strip with a triple-fin vinyl seal, and the maker lists it as sealing gaps up to 1 inch. You cut the aluminum with a hacksaw, trim the vinyl with scissors, peel the liner and press it to the door. The adhesive is 3M and no hardware is required. The catch is the surface. Adhesive holds best on a clean, flat door bottom, and doors that flex or have textured finishes can let it lift over a winter of swinging. It also seals against the side of the threshold, so check that your threshold suits that before you buy. The maker page lists no warranty. It depends on your door: good for a rental with a smooth door, a worse bet if you need the strip to last for years.

A fabric draft snake is the most commonly bought fix and the weakest on evidence. The Frost King Double Draft Stop (DDS1) is a brown, 1-1/4 inch wide tube up to 36 inches long that you slide under a door. The maker says it insulates both sides of a door or window at once, blocks drafts and dust, and reduces energy loss. The page does not name the cover material, mentions foam tubes only in the FAQ, and gives no figures for how much it helps. It also states it is not rigid enough to stop all bugs from crawling under a door. A snake sits loose on the floor, so it slides and has to be repositioned, and it does not close a gap the way a screwed or stuck sweep does. It is fine as a temporary block on a door you rarely open. For a door you use every day, buy a sweep.

Frost King Premium Aluminum and Reinforced Rubber Door Sweep (A79/36A) vs Duck Brand Rolled Shrink Film Window Insulation Kit, 62 in. x 210 in. (5 windows): which should you buy?

The Frost King sweep and the Duck film kit solve different gaps, so they are not really rivals. The sweep fixes the bottom of an exterior door for good and carries a lifetime guarantee on the rubber. The Duck kit covers windows for one winter and then comes off. If your cold spot is a door, buy the sweep. If it is a window, buy the film.

If you have both problems, buy both, since together they cost little. If you cannot drill into your door, the M-D CINCH is the alternative to the Frost King. Pick the screw-on sweep when you own the door and plan to stay, and pick film for any window you cannot replace.

What to look for

• Sweep over snake: a sweep fixed to the door closes the gap each time the door shuts, while a loose snake moves when you use the door.
• Install method: screw-on is the most durable, stick-on is easiest and best for renters, and film needs tape plus a hair dryer.
• Stated size: match the length to your door width and check the gap range, since the CINCH lists gaps up to 1 inch.
• Adjustability: look for a sweep you can cut to length and set to the right height so it touches the threshold without dragging.
• Material named: a maker that names the material and gives sizes is easier to trust than one with general claims only.
• Surface limits: film and adhesive both depend on a clean, dry, suitable surface, so read the warnings about plaster, drywall and unfinished wood.

Our final take

For a door, buy the Frost King A79 sweep and install it properly. For windows, the Duck film kit is the simplest winter fix, and it comes off in spring. Pick the M-D CINCH only if you cannot drill and your door bottom is clean and flat. Skip the Frost King Double Draft Stop, because a loose foam tube with a vague maker page is a stopgap, not a fix. Whatever you pick, measure the door and check the gap first, because the right type for your gap matters more than the brand.

Deciding between the top two? See our head-to-head: Frost King Premium Aluminum and Reinforced Rubber Door Sweep (A79/36A) vs Duck Brand Rolled Shrink Film Window Insulation Kit, 62 in. x 210 in. (5 windows).

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