The first cold night in our old rental taught me something I should have known: my curtains were moving, and nobody was touching them. I stood at the living room window holding a candle, watched the flame lean sideways, and realized the heating bill was escaping through a gap I could fit a fingernail into. Learning how to weatherproof windows for winter turned out to be one of the cheapest, fastest projects I have ever done, and I did it with a caulk gun, a hair dryer and a rolled-up towel. Because I link to a few of the supplies I used, I will be upfront: as an Amazon Associate, I earn from qualifying purchases, which costs you nothing extra and helps keep this blog running. Here is the exact order I follow every October, so you can finish before the first freeze.
How Do You Weatherproof Windows for Winter?
To weatherproof windows for winter, find the leaks first, then seal them in layers: caulk the gaps around the frame, add weatherstripping to the parts that move, cover the glass with shrink film, block the sill with a draft stopper, and finish with thermal curtains. Most homes can do all five in a single weekend.
Think of it as stacking small wins. Each layer stops a different kind of heat loss, and none of them requires replacing a window, which can cost thousands. The Virginia Energy Sense program notes that up to 30 percent of a home’s heat can escape through windows, and says homeowners can save up to 10 percent a year just by sealing and insulating them. You can read their full rundown on DIY window insulation tips. If your goal is a lower bill overall, our list of heating bill finds to buy before winter hits pairs nicely with this project.
What Materials Do You Need to Insulate Windows?
Gather everything before you start, because the work goes quickly once you are in a rhythm. This is the full list for a typical house with six to ten windows.
- Caulk gun and a tube of exterior-grade latex or silicone caulk
- Putty knife or flat screwdriver for removing old caulk
- Self-adhesive foam tape or V-strip weatherstripping
- Window insulation film kit (film, double-sided tape)
- Hair dryer
- Draft stoppers (store-bought, or an old sock and some rice)
- Thermal curtains and a rod wide enough to cover the frame
- Rope caulk for leaky windows you never open
- Scissors, utility knife, measuring tape, damp cloths, a candle or incense stick
Budget is modest. The U.S. Department of Energy rates the caulking project as easy, at roughly $3 to $30 and one to two hours of work, with energy savings of 10 to 20 percent. Weatherstripping a double-hung window is rated moderate, about $5 to $10 and an hour per window, for 5 to 10 percent savings. The caulking numbers come from the Energy Department’s seal air leaks with caulk guide, the weatherstripping ones from its double-hung window weatherstripping project, and your own results will vary with the age and condition of your windows.
Step 1: How Do You Find Drafty Windows?
Do this on a cold, breezy evening with the heat running. Close the window, turn off ceiling fans, and hold a lit candle or a stick of incense about an inch from the frame. Move slowly along all four sides, the meeting rail where the two sashes join, and the sill. If the flame flickers or the smoke streams sideways, you have found a leak.
Mark each spot with a small piece of painter’s tape. A quick no-flame version works too: run the back of your hand along the frame and feel for cold air. Also check where the trim meets the wall and around nearby outlets and exhaust fans, since drafts like to show up in unexpected places.
Write down which windows are worst. You will start with those, and the Energy Department gives sensible advice on order of attack: “Air takes the path of least resistance, so you should aim to seal the big holes first.”
Step 2: How Do You Caulk Windows for Winter?
Caulk is for gaps that never move, such as the joint between the window frame and the siding or interior trim. Do not caulk the moving parts of the sash, because you will glue your window shut. Plan on roughly half a cartridge per window, according to the Energy Department.
Good caulk work is mostly preparation. The caulk gun and tube are the heart of this step, and a smooth, dripless gun makes the bead far neater, so it is worth skipping the flimsiest model. Look for a tube labeled for exterior use and rated for temperature swings.
Shop caulk guns and exterior window caulk on Amazon
Caulking steps
- Clean the joint. Scrape out old, cracked caulk and loose paint with a putty knife or screwdriver, then wipe the area and let it dry completely.
- Cut the tip. Snip the nozzle at a 45-degree angle, making the opening only as wide as the gap. Practice a line on newspaper first.
- Apply one steady bead. Hold the gun at roughly 45 degrees to the crack and pull it toward you in a continuous line, rather than pushing it.
- Tool the bead. After two or three feet, dampen a fingertip and press the caulk into the crack for a smooth, sealed joint.
- Wipe and cure. Clean off smears right away with a damp rag, and allow the full cure time on the package, typically about 24 hours.
One more tip: caulk does not last forever. Tom’s Guide recommends redoing it about every five years, depending on quality, so check yours each fall. If you are in the middle of a bigger refresh, our guide to making DIY cafe curtains is a good companion project for finishing a freshly sealed kitchen window.
Step 3: What Is the Best Weatherstripping for Windows?
For the parts that open and close, you need weatherstripping, which compresses to make a seal when the window is shut. The right type depends on the gap and how much friction the strip will face.
- Self-adhesive foam tape: the easiest choice. Cut it to the length of the sash and press it onto the top and bottom of the window sash.
- V-strip (tension seal): a folded strip of vinyl or metal that springs open to fill the side channels of double-hung windows. Home Depot notes that nailed-in V-strips are more secure than adhesive-backed versions, though harder to install.
- Felt: cheap but short-lived. As Home Depot puts it, “Felt is an inexpensive choice, but it tends to last only a year or two.”
- Tubular vinyl or silicone gaskets: flexible barriers that adapt to uneven surfaces; good for older, warped frames.
For most renters and first-timers, adhesive foam or rubber strips are the sweet spot. They cost little, cut with scissors, and come off cleanly at the end of a lease. The key is measuring honestly, because a gap you skip is a gap that still leaks. The Energy Department suggests totaling the perimeter of all your windows and adding about 10 percent for waste.
Browse self-adhesive window weatherstripping on Amazon
Weatherstripping steps
- Wash the frame with soap and water and let it dry fully, since tape will not stick to dust or damp wood.
- Measure each side and cut the strip, adding about an inch if you are fitting V-strip.
- Open the window fully and press the strip into the channel or along the sash edge, peeling the backing a few inches at a time.
- Close the window and check that it latches without binding. If it fights you, the strip is too thick.
- Repeat on the lower sash, the upper sash, and the bottom edge so the material compresses when the window closes.
Step 4: How Do You Put Plastic Insulation Film on Windows?
Window insulation film is the dramatic upgrade in this guide. Tom’s Guide describes it as “essentially a large sheet of shrink-wrap plastic with some double-sided adhesive tape,” which is exactly right. You stick the tape around the frame, attach the film, and shrink it tight with a hair dryer. The sealed pocket of air between film and glass cuts drafts and adds an insulating layer, and when you press it flat it is nearly invisible.
Kits usually cover three to five standard windows. Choose a kit sized to your biggest window, and buy extra for sliding glass doors. Use film on windows you rarely open, because you will need to peel it off to use the window.
See indoor window insulation film kits on Amazon
Window film steps
- Clean and dry. Wipe the frame and glass with a damp cloth and let everything dry, because the tape needs a clean surface.
- Apply the tape. Stick double-sided tape to the flat part of the frame all the way around, pressing it firmly into corners.
- Cut the film. Unroll it and cut a piece a couple of inches larger than the window on every side.
- Attach the film. Starting at the top, remove the tape backing and press the film on, smoothing downward to avoid big wrinkles.
- Shrink it. Run a hair dryer on high, a few inches from the film, until it pulls tight and clear. Do not hold it in one spot.
- Trim the edges. Cut off the excess with a utility knife for a tidy finish.
Home Depot also lists a version that uses a spray bottle and squeegee, which suits glass-mounted film designed to be reusable. Whichever type you buy, follow the packaging, because the shrink method and the squeegee method are not interchangeable.
Step 5: How Do You Use Draft Stoppers on Windows?
A draft stopper, sometimes called a draft snake, is a fabric tube that sits along the sill or the bottom of the sash and blocks low, creeping cold air. Tom’s Guide describes it as a stuffed foam and fabric tube you place horizontally along the base of your window. It takes ten seconds to use and removes cleanly in spring, so it is perfect for rentals and for windows you open often.
Buying one saves time, but making one is easy. Fill a long sock or a sewn fabric tube with dry rice, beans or sand, tie off both ends, and lay it along the sill. A heavier fill holds its shape better than a floppy one. For tall frames, place two stoppers end to end. If a sill is too narrow for a tube, tuck a rolled towel behind the curtain.
Compare draft stoppers for windows on Amazon
If your window sits in a reading corner, this is a great excuse to build one. Our walkthrough on building a DIY window seat reading nook with storage shows how to turn a chilly spot into the coziest seat in the house once it is properly sealed.
Step 6: Do Thermal Curtains and Cellular Shades Really Help?
Yes, as a final layer. Heavy curtains and cellular (honeycomb) shades trap air against the glass, so the room loses less warmth at night. Virginia Energy Sense notes that heavy curtains retain daytime heat and reduce nighttime losses, while Tom’s Guide points out that they cost more than sealing methods. That is why they come last: seal the leaks first, then add fabric.
For the best result, hang the rod a few inches above and wider than the frame so the curtain overlaps the wall, and let the panels reach the sill or the floor. Open them on sunny days to let free heat in, and close them at dusk. If you want a refresh that goes beyond weatherproofing, our roundup of cozy fall home finds shoppers keep reordering has more ideas for warming up a room.
Find thermal insulated curtains on Amazon
Can Renters Weatherproof Windows Without Damaging Anything?
Absolutely. Every method below removes without harming paint or trim.
- Rope caulk: a pliable putty you press into gaps with your fingers, with no tools or drying time. Bob Vila lists it as a temporary fix for small cracks, and it peels away in spring.
- Film that attaches with removable tape or magnets: Home Depot mentions magnetic tape as a removable alternative.
- Draft stoppers and rolled towels: zero installation.
- Plug-and-pull curtains: a tension rod and a pair of lined curtains do the job.
Rope caulk is the one I recommend most often for old single-pane windows you will not open until April. Pack it into the gap between sash and frame, press until it is snug, and trim stray bits.
Shop removable rope caulk on Amazon
Weatherproofing also fits into the broader trend of homeowners fixing what they have instead of replacing it, which we covered in the repair economy and why 2026 spending turned practical.
When Should You Weatherproof Windows Before Winter?
Aim for early to mid fall, before nights drop below freezing. Caulk and window tape both need a dry surface and moderate temperatures, and most caulk labels list a minimum application temperature, so read yours. If you wait until the first cold snap, you will be working in a cold house with cold fingers.
A simple fall schedule keeps it painless. Do the leak test in the first week of October, caulk and weatherstrip the following weekend, and install film and curtains right before heating season begins. Then recheck everything each year, because as Virginia Energy Sense warns, “Caulk and weatherstripping can dry out or shrink over time.”
Mistakes to avoid
- Caulking over dirt, old paint flakes or damp wood, which causes peeling within months.
- Caulking the sash itself and painting your window shut.
- Using thick weatherstripping on a tight window, which can keep it from latching.
- Applying film to a cold, dusty frame, so the tape lets go in a week.
- Sealing every vent in the house. Keep fresh air moving, especially near gas appliances, and never block bathroom or kitchen exhaust.
For a bigger picture of preparing a house for harsher weather, read our look at climate-proofing your home, and keep the weatherproofing in mind as the foundation of any winter prep plan.
Frequently Asked Questions
What is the cheapest way to insulate windows for winter?
The cheapest options are rope caulk, adhesive foam weatherstripping and a homemade draft stopper made from a sock and rice. Each costs only a few dollars, according to the Energy Department’s project estimates of $3 to $30 for caulking and $5 to $10 for weatherstripping. Plastic film kits are the next step up and are still inexpensive.
Does window insulation film really work?
Yes, when it is installed airtight. The film creates a sealed air pocket against the glass and blocks drafts, and a hair dryer tightens it. Tom’s Guide calls it essentially shrink-wrap with double-sided tape. It works best on single-pane or older windows you will not open all winter, and it can be removed in spring.
How much energy can you save by sealing windows?
It depends on how leaky your home is. The Department of Energy estimates 10 to 20 percent savings for air sealing with caulk, and 5 to 10 percent for weatherstripping double-hung windows. Virginia Energy Sense says homeowners can save up to 10 percent annually by sealing and insulating windows. Older homes with visible gaps tend to gain the most.
Should you caulk or weatherstrip drafty windows?
Use both, for different jobs. Caulk fills stationary gaps, like the joint between the frame and the wall, while weatherstripping seals the moving parts, such as the sash and the meeting rail. Caulking a moving part can glue the window shut, so match the product to the type of gap you find.
Weatherproofing windows is not glamorous, but it is the rare project where one weekend and a few dollars changes how the whole house feels: no cold spot by the sofa, no curtain swaying in a draft, and a thermostat that stops fighting you. Start tonight with a candle test at your worst window, caulk and weatherstrip it this weekend, and add film and a draft stopper before the first freeze. By January you will be glad you did.