A window insulation kit is the cheapest real upgrade an old or drafty window can get. For the price of a takeout lunch you tape a sheet of clear plastic over the inside of the frame, shrink it tight with a hair dryer, and the cold air that slid around the sash all winter is gone. The Department of Energy estimates that about 30% of a home’s heating energy is lost through windows, which is why this fix makes such a noticeable difference on single-pane glass.
For most homes, the Duck Brand Window Insulation Kit (10 windows) is the best buy: two cut-to-size rolls that fit almost any window. For standard-size windows, the Frost King 9-pack of pre-cut sheets is simpler. Pets or kids? Get the twice-as-thick Duck MAX Strength. A sliding door you keep closed all winter needs a patio door kit.
Affiliate note: As an Amazon Associate, The Low Bill Home earns from qualifying purchases. Buying through our links costs you nothing extra. We have not tested every product hands-on: picks are based on the makers' published specs, official energy-saving guidance and long-term buyer feedback, and we say where a product falls short.
Two 62-inch-wide rolls you cut to size, enough for up to ten 3 x 5 ft windows.
Check price on AmazonWhy we picked it ↓Nine pre-cut 42 x 62-inch sheets: no measuring rolls, one sheet per window.
Check price on AmazonWhy we picked it ↓Film about twice as thick as standard kits and puncture-resistant.
Check price on AmazonWhy we picked it ↓Shopping on Black Friday? Add it to your Amazon cart now so it is ready when the deals start (Black Friday is November 27, Cyber Monday November 30, 2026).
Which kit for which window
Measure the outside edge of the trim you will tape to, not the glass. The film has to be a little bigger than that area, about an inch extra on every side, so you have something to hold while you press it on.
| Your windows | Best kit type | Our pick |
|---|---|---|
| Mixed sizes, or windows up to about 5 ft in one direction | Cut-to-size rolls | Duck 10-window kit |
| Standard double-hung windows, trim no larger than about 40 x 60 in | Pre-cut sheets | Frost King 9-pack |
| Cats, dogs, kids, or a window you bump into | Heavy-duty film | Duck MAX Strength |
| Sliding patio door or picture window you keep closed in winter | Extra-large sheet | Frost King V76H |
| A window you cannot film, or small gaps at the sash only | Clear sealing tape | XFasten clear tape |
| A window you must be able to open | No film: thermal curtains and removable caulk | Thermal curtains |
Comparison table
Contents and sizes as listed by the makers on Amazon in October 2026.
| Kit | Film | Covers | Tape | Best for |
|---|---|---|---|---|
| Duck 10-window | 2 rolls, 62″ x 210″ | Up to ten 3 x 5 ft windows | 2 rolls, 0.5″ x 83 ft | Most homes |
| Frost King V73/9H | 9 pre-cut sheets, 42″ x 62″ | Nine standard windows | Included | Standard sizes |
| Duck MAX Strength | 1 roll, 62″ x 210″, about 2x thicker | Up to five 3 x 5 ft windows | 1 roll, 0.5″ x 84 ft | Pets, kids, high traffic |
| Frost King V76H | 1 sheet, 84″ x 110″ | One patio door or big window | Included | Doors kept closed in winter |
| XFasten clear tape | Tape only, 2″ x 30 yd | Sash gaps and seams | — | Odd frames, quick seals |
How we chose
- Proven brands. Duck and Frost King have sold window kits for decades and dominate this category. 3M’s indoor kits are also widely sold, but buyer feedback on their tape is more mixed, so we left them out.
- The right format for the window. Rolls for mixed sizes, pre-cut sheets for standard windows, heavy film for homes with pets, an extra-large sheet for patio doors.
- The complaints. The common failures are tape letting go and film tearing. We say how to avoid both in the install guide below.
We have not tested these products in our own home. Picks are based on the makers’ published specifications, safety certifications and patterns in long-term buyer feedback, especially the complaints.
The picks
Duck Brand Window Insulation Kit (10 windows)
The kit most people should buy. Instead of pre-cut sheets it comes as two 62-inch-wide rolls, so you unroll and cut exactly what each window needs, from a narrow bathroom window to a wide living-room one. The rolls cover up to ten standard 3 by 5-foot windows, and the double-sided tape is included. All you need is scissors and a hair dryer. Once tightened, the film is crystal clear, and it comes off at the end of the season.
- 2 rolls of film, 62″ x 210″ each
- 2 rolls of tape, 0.5″ x 83 ft
- Up to ten 3 x 5 ft windows
- For painted or finished wood, aluminum or vinyl
Good: fits almost any window, very clear once shrunk, enough for a whole small house.
Watch out: you cannot open the window until spring; the tape can lift fresh paint and is not for drywall or plaster.
Skip it if: every window you have is the same standard size: pre-cut sheets are quicker.
Frost King V73/9H Indoor Shrink Window Kit (9-pack)
If your windows are ordinary double-hung windows, pre-cut sheets save the fiddly part. You get nine 42 by 62-inch sheets with tape, one per window. Frost King is honest in its own listing that the tape can eventually fail from sunlight and the window’s normal movement, and suggests a fresh kit every year, which matches how these kits work in practice.
- 9 pre-cut sheets, 42″ x 62″
- Tape included
- Indoor use
- One sheet per standard window
Good: no measuring or cutting rolls, easy to do one room at a time.
Watch out: sheets cannot cover trim wider than about 40 inches or taller than about 60; plan on a new kit each fall.
Skip it if: your windows are large or unusual sizes.
Duck MAX Strength Window Insulation Kit
Standard film is thin, and a curious cat or a stray elbow can split it. Duck’s MAX Strength film is about twice as thick as its standard kits and puncture-resistant, while still clear once shrunk. This version is one 62 by 210-inch roll with tape, enough for five standard windows; a ten-window size is also sold.
- 1 roll of film, 62″ x 210″, about 2x standard thickness
- 1 roll of tape, 0.5″ x 84 ft
- Up to five 3 x 5 ft windows
- Cut to size
Good: resists pets, kids and bumps, still very clear.
Watch out: covers fewer windows per box than the standard kit; thicker film takes a little more heat to shrink.
Skip it if: nothing is likely to touch the windows: the standard kit covers twice as many.
Frost King V76H Patio Door Shrink Kit
Sliding glass doors are often the coldest spot in a house. This kit is one big 84 by 110-inch sheet, large enough to cover a standard patio door or a picture window in one piece. The obvious catch: once it is on, that door is closed until spring, so use it only on a door you do not need in winter, and never on a door that is a required exit.
- 1 sheet, 84″ x 110″
- Tape included
- Indoor use
- For patio doors and large windows
Good: one-piece coverage for the biggest, coldest glass in the house.
Watch out: the door cannot be used until you remove the film; big sheets are easier with two people.
Skip it if: you use the patio door in winter: close thermal curtains over it at night instead.
XFasten Transparent Window Weather Sealing Tape
Some windows do not suit a film kit: odd shapes, narrow basement windows, frames with no flat trim, or the gaps around a window air conditioner. Clear sealing tape goes straight over the gap between sash and frame and stops the air without blocking the view. XFasten’s 2-inch tape is made to stay put through temperature swings and, according to the maker, removes without residue. A 30-yard roll does a lot of windows.
- 2″ wide x 30 yards
- Clear, pressure-sensitive adhesive
- Maker says it removes cleanly
- For window seams, sash gaps and AC unit gaps
Good: nearly invisible, quick, works where film cannot.
Watch out: seals gaps but does not add the insulating air layer that film does; the window stays shut while taped.
Skip it if: the whole window feels cold, not just the edges: use film.
How to install it (and remove it in spring)
- Pick a mild day, and keep the heat on. The tape bonds best at room temperature. Install indoors with the room warm.
- Clean and dry the trim. Wipe it with a little rubbing alcohol. Dust and grease are why tape fails.
- Tape the trim. Run the double-sided tape around the face of the trim, pressing firmly. Leave the paper backing on for now.
- Cut the film about an inch bigger than the taped area on every side.
- Attach the top first, then the sides, then the bottom, peeling the backing as you go. Do not stretch it; small wrinkles disappear in the next step.
- Shrink it. Hair dryer on high, held a few inches from the film, moving steadily. Start at the corners and work toward the middle. Never touch the film with the dryer.
- Trim the excess with a sharp blade along the outside edge of the tape.
In spring: warm the tape with the hair dryer and peel it back slowly, pulling along the surface, not straight out. Leftover adhesive usually comes off with rubbing alcohol.
Film vs curtains vs tape vs bubble wrap
| Option | Stops drafts | Insulates glass | Window usable | See through |
|---|---|---|---|---|
| Shrink film kit | Yes | Yes (still-air layer) | No, until spring | Yes |
| Thermal curtains | Partly, when closed | Some, at night | Yes | No, when closed |
| Clear sealing tape | Yes, at the seams | No | No, while taped | Yes |
| Removable caulk cord | Yes, at the seams | No | No, until removed | Yes |
| Bubble wrap on the glass | No | Some | Yes | Blurry |
The best combination for a cold room is film on the windows you never open, plus thermal curtains closed at night. For a window you need to open, use removable caulk cord in the gaps and curtains over the glass. Note that tinted or solar-control window films are a different product: the Department of Energy’s Building America Solution Center notes they can increase winter heating needs.
Mistakes to avoid
- Taping to drywall or plaster. It will pull off paint and paper in spring. Tape to trim only.
- Stretching the film by hand. Let the hair dryer do the tightening, or the film tears at the tape.
- Filming every window in a bedroom. Keep one window that opens, for ventilation and as an emergency exit.
- Covering a drafty frame but ignoring the door. The gap under the door is often just as bad: see the best door draft stoppers.
FAQ
Do window insulation kits really work?
Yes, especially on single-pane and drafty windows. The film stops air leaking around the sash and holds a layer of still air in front of the cold glass, which is why a room feels less drafty the same day. The gain is smaller on modern double-pane windows that already seal well.
Will a window insulation kit damage my paint?
The double-sided tape can lift fresh or poorly bonded paint and should not go on drywall, plaster or unfinished wood. Apply it to painted or finished wood, vinyl or aluminum trim, and in spring warm the tape with a hair dryer and peel it back slowly along the surface.
Can I open the window with plastic film on it?
No. Once the film is on, the window stays closed until you remove it in spring. Leave one window per room unfilmed if you need it for ventilation or as an emergency exit, and seal that one with removable caulk cord or clear sealing tape instead.
Should window insulation film go inside or outside?
Standard kits are made for the inside of the window, where the tape stays dry and the film is protected from wind. Outdoor kits exist but are less common and harder to keep tight.
How long does window shrink film last?
One heating season. Sunlight and the window's normal movement eventually loosen the tape, so plan to remove it in spring and apply a fresh kit next fall.
Is window insulation film the same as window tint film?
No. Shrink film kits create an air barrier in front of the window. Tinted or solar-control window films stick directly to the glass to block sun; the Department of Energy's building research program notes these films can actually increase winter heating needs, so they are a summer product.
Keep going
- Best thermal curtains and how to hang them
- How to stop window and door drafts: 7 cheap fixes
- How to keep a cold bedroom warm at night
- 20 ways to lower your heating bill this winter
Sources
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