Chilly winds might be the first sign you have a draft problem, but leaky windows and doors aren’t just a winter nuisance. Drafts can undermine your comfort and energy efficiency all year long, whether you're heating your home in the colder months or trying to keep it cool during the summer.

One of the best ways to combat this is by focusing on your windows, doors, and other areas prone to air leakage. Year-round weatherproofing not only lowers your energy bills and carbon footprint but also helps maintain a comfortable indoor temperature in every season.

Roller blinds in a modern bedroom with an arched wall headboard detail.
Using smart shades and curtains can improve energy efficiency year-round. Credit: Graber

Why It’s Important to Seal Drafts

"Proactive home maintenance will always be an optimal option versus reactive home maintenance," shares Anthony Perera, Founder of Peak Roofing Partners. "Ensuring that your roof, windows, and doors are properly sealed and secure throughout the year will afford you the necessary time to have repairs and maintenance completed before winter temperatures set in, or you're faced with a catastrophic weather event."

Before we dive into the how-to, let’s quickly talk about the "why." Drafty windows and doors can account for up to 25-30% of heat loss in a home, according to the U.S. Department of Energy. Westlake Royal Building Products notes that about 25% of energy escapes through the roof as well.

This isn't just a cold-weather issue. In hot climates, the same gaps that let in cold air during winter also allow cool, conditioned air to escape, raising your energy costs and stressing your HVAC system.

By sealing these gaps with cost-effective solutions like foam tape, weatherstripping, or window film, you can retain both heat and cooled air. This leads to tighter seals, reduced heat transfer, and fewer hot or cold spots in your home. Whether you’re dealing with a drafty spot in January or struggling to retain AC in August, a little preventative maintenance goes a long way. A win-win!

A person uses a weighted strip to prevent drafts under the door.
Prevent drafts around your windows and doors to save energy and keep your home warm this winter. Credit: daisy-daisy / Getty Images

Step-by-Step Weatherproofing for Year-Round Comfort

1. Inspect for Drafts

The first step is locating the source of air leakage. A super simple way to do this is the "candle test." Light a candle and hold it near the edges of your windows and doors. If the flame flickers or blows out, you've found a draft.

Jeramy Sibley, the President of Glass Doctor, a Neighborly company also cites a (flame-free) technique known as the "paper test," explaining "You can use a paper to test for drafts around the window by closing a piece of paper in the door or window jamb; if it slides out easily, there's a gap."

Mark those spots so you can come back to them and create a tighter seal.

2. Seal Gaps and Cracks

Once you've identified the drafty areas, it's time to seal them. "Windows are one of the most common places for leaks that let in cold winter air and moisture," highlights Kriss Swint, director of marketing communications and design lead at Westlake Royal Building Products.

The same holds true for warm air in summer.

She highlights that homeowners should "check for air leaks, clean the window tracks of any debris that may interfere with seals and repair any missing or damaged sealant."

Clean out window tracks with a putty knife. Use caulk or rope caulk to close off gaps, especially around window casings or older, single-pane windows.

These practical solutions help create a tight seal that reduces air leakage and energy consumption.

Man adds weatherstripping to the area around windows and doors.
Weatherstripping helps seal gaps in windows and doors. It's easy to install, and affordable, too. Credit: Availablelight / Getty Images

3. Apply Window Film

For windows that are especially prone to cold drafts, consider adding a layer of transparent window film. It isn't a permanent solution, but plastic sheeting is a quick, cost-effective way to improve insulation without blocking your view or light.

Plastic film offers an additional layer of insulation to drafty windows year-round. It’s not just a winter hack—during warmer months, it can help reflect solar heat and block UV rays. This temporary solution attaches with double-sided tape and is tightened using a hair dryer to create an airtight seal.

4. Install Draft Stoppers or Door Sweeps

Gaps at the bottom of doors are a major culprit for energy loss. "Door sweeps create an airtight seal underneath entryways, another common leak location," notes Swint. "They come in two forms: u-shaped pieces that slide under aluminum or steel doors and metal strips that screw, nail or staple to door bottoms."

She adds, "Door sweeps have an attached strip made of vinyl, plastic, sponge brush or other air-blocking material. Use it to fill the gap between the bottom of your door and the threshold. To install, measure your door, fit the strip (cut to the correct length if necessary), drill pilot holes and tighten with screws."

Fabric draft stoppers are another option, and they're particularly nice for renters. These draft guards can be used seasonally to manage both cold drafts and summer air conditioning loss.

Testing the attic insulation with thermal imaging.
How to Test HVAC Energy Efficiency
The National Comfort Institute shared three ways homeowners can check for air flow issues within their HVAC system.
Read More

5. Use Insulating Window Treatments

Another easy way to prevent heat loss is by installing insulating curtains or heavy drapes. Heavy fabric, like thermal-lined curtains, acts as an extra layer of insulation for your windows.

Consider installing cellular shades or layered curtains for a cost-effective solution that works year-round. Close-fitting drapes add another layer of protection against unwanted heat transfer.

6. Expose Air Vents

"Consider rearranging your rooms," recommends Swint, as she cautions that furniture can trap heat or cooled air in the wrong spots. "If you’re struggling to find a perfect arrangement for your furniture, do your best and then supplement with a vent extenders or deflectors. These nifty little tools push air into a part of the room that your vent doesn’t reach, whether because of placement or obstruction."

A modern living room with big, potentially drafty, windows.
Insulate your windows in your home or apartment. Credit: Morsa Images / Getty Images

7. Install Storm Windows and Doors

If your home has storm windows or storm doors, now’s the time to make the extra glass pane is properly installed and in good condition.

While often thought of as a winter upgrade, storm windows and doors also reduce energy loss from air conditioning. Double-hung windows provide an additional glass pane and air pocket that minimizes temperature fluctuations and outdoor air infiltration.

8. Replace or Upgrade Weatherstripping

Weatherstripping wears down over time. "[Updating] your windows’ interiors with felt rolls, foam tape, or rope caulk is a cost-effective solution for older windows with worn out putty or insufficient sealing and caulking," notes Swint. "For the exteriors, sealing cracks or gaps with decorative trim can make a difference in keeping the heat in and chilly air out."

You can pick up weatherstripping at any hardware store—it’s affordable and easy to install. Just make sure to follow the package instructions to get the best fit.

A thermal camera on a smartphone highlights where heat is lost between attic joists.
Improve your attic insulation while you can. Finder S2 is a sample that was sent to me, and it works really well. Credit: Emily Fazio

9. Insulate Your Attic

“Approximately 25% of a home’s heat escapes through the roof,” reminds Swint. But in summer, poor attic insulation also lets excessive heat in.

Upgrading your attic insulation with fiberglass, rockwool, or cotton helps maintain a more stable indoor temperature and can reduce your heating and cooling costs.

Air conditioning units in the windows on a brick building.
How to Insulate a Window AC Unit For Winter
Special insight for both homeowners and apartment dwellers!
Read More

Extra Tips for Maximizing Energy Efficiency

  • Switch to energy-efficient windows: If sealing and temporary fixes aren’t cutting it, consider window replacement. Energy-efficient windows—like double-pane or low-emissivity glass—offer excellent insulation against both cold and heat. “If you notice unwanted condensation inside the window glass or around the perimeter, these could be signs that the seal is failing,” notes Sibley.
  • Use draft snakes: These handy fabric tubes can block cold air in winter and retain cooled air in summer. Use them on window frames, door bottoms, or wherever a drafty gap exists.
  • Weatherproofing kits: Look for all-in-one weatherproofing or window insulation kits, which usually include weatherstripping, plastic sheets, and adhesive tape. These cost-effective solutions can quickly enhance your home’s airtight seal and reduce your utility bills throughout the year.