Best Window Insulation Kits for Drafty Windows (2026)

Buy the 3M Indoor Window Insulator Kit if you want the cleanest default for several standard windows. Its tape-and-film system is the best all-around choice in Bob Vila’s hands-on testing, and the five-window format is enough for a small room or two.

If coverage is the priority, the Duck Brand Indoor 5-Window Shrink Film Insulator Kit is the budget pick. If the film will live around pets, kids, or a high-traffic room, spend more for the heavier Duck MAX Strength kit. First, make sure film is the right fix: our repair guide shows how to separate a temporary comfort measure from a leak or damaged frame that needs repair.

Quick comparison

Top pick: 3M Indoor Window Insulator Kit, 5-window pack

The 3M Indoor Window Insulator Kit is our buy-for-most-people choice. Bob Vila’s 2025 hands-on test named the 3M kit Best Overall, citing film that can be repositioned before it is pressed down and wrinkles that shrink out quickly with a hair dryer. The five-window pack is sized for up to five standard 3-by-5-foot interior windows.

Why it wins:

• It is the strongest all-around option in an independent hands-on comparison.
• The 3M kit’s tape-and-heat-shrink approach is familiar and manageable for a first-time installer.
• One package can cover several standard windows without buying separate sheets.

Watch out for:

• Finding the edge of the film can be a small nuisance. Like other film kits, it is a seasonal setup: a covered window generally should not be opened until the film comes down.

Budget pick: Duck Brand Indoor 5-Window Shrink Film Insulator Kit

Choose the Duck Brand Indoor 5-Window Shrink Film Insulator Kit when you have several ordinary windows to cover and want to keep the outlay down. The roll is cut to fit, and Duck’s instructions for its rolled kits call for clean, dry painted or finished wood, aluminum, or vinyl frames. The clear film is meant to preserve daylight while creating another interior air barrier.

Why it wins:

• It covers up to five standard windows at a lower typical price than the heavier-duty option.
• Rolled film lets you size each piece to the frame rather than work around a pre-cut sheet.
• Duck’s standard shrink-film format is intentionally simple: tape, film, then a hair dryer to tighten it.

Watch out for:

• This is standard film, not the brand’s puncture-resistant MAX Strength film. A window beside active pets or a busy doorway is a better case for the upgrade.

Upgrade pick: Duck MAX Strength Heavy Duty Insulating Film Window Kit

The Duck MAX Strength Heavy Duty Insulating Film Window Kit is the sensible upgrade when ordinary thin film is likely to take a hit. Its 1.5-mil film is twice the thickness of many standard kits, according to Duck and Bob Vila’s product comparison. This three-window size covers up to three standard 3-by-5-foot windows, so it makes most sense for a small set of vulnerable openings rather than a whole house.

Why it wins:

• The heavier, puncture-resistant film is better suited to high-traffic rooms and homes with pets.
• It still uses the familiar interior tape-and-heat-shrink installation.
• Independent testing identifies the 1.5-mil construction as a meaningful distinction from standard film.

Watch out for:

• You pay more per covered window, and this three-window kit does not stretch as far as a five-window standard kit.

How we chose

We limited this list to interior shrink-film kits because they solve the same seasonal problem: reducing the chilly airflow and cold-surface feeling around a drafty window without altering the window permanently. We compared fit, coverage, film thickness, installation approach, and where the extra cost makes sense.

Bob Vila’s hands-on testing supplied the independent product comparison. We then checked manufacturer documentation for the products’ intended use and sizing. We did not treat advertised energy savings as a promise: house condition, installation quality, climate, and the underlying window all matter. Film is also not a cure for rot, water entry, failed glazing, or a sash that will not close.

Troubleshooting & FAQ

Are window insulation kits worth it?

They can be worth it as a low-cost seasonal measure when the issue is a cold, drafty room and the window is otherwise sound. They add a still-air layer on the room side of the window. They will not repair damaged frames, leaking water, or broken hardware.

What size window insulation kit do I need?

Measure the frame opening you plan to cover, then compare it with the kit’s stated coverage. The 3M and standard Duck picks here are intended for up to five standard 3-by-5-foot windows. The Duck MAX Strength pick covers up to three. Leave enough film to tape all four sides before trimming.

Can I open a window after installing shrink film?

Not normally. The film is taped across the interior frame and shrunk tight, so opening the sash will break the seal. Reserve film for windows you can leave closed for the season, and keep an accessible egress window where local safety rules require one.

Do I need a hair dryer?

Yes. A hair dryer tightens the film after it is taped in place, which removes wrinkles and makes the layer clearer. Follow the kit’s temperature and distance instructions; do not use an open flame or a high-heat tool that could damage the film or paint.

Why is there condensation after I put up the film?

Condensation can signal humid indoor air meeting a cold surface, an incomplete seal, or a window problem outside the film’s scope. Check that the frame is dry and the tape is fully adhered. If water is entering the frame or condensation persists between panes of insulated glass, investigate the window itself.