How to Seal Drafty Windows and Doors for Better Insulation
Does your home feel colder than it should in the winter, even when the heat is on? Or do you notice your air conditioner running nonstop in the summer? If so, drafty windows and doors could be silently sabotaging your comfort and energy efficiency. These air leaks not only make your living space less comfortable but also force your HVAC system to work overtime—leading to higher utility bills and unnecessary wear on your heating and cooling equipment.
The good news is that sealing these leaks is both easy and affordable. With just a few tools and materials, you can reduce drafts, save money, and improve your indoor comfort year-round.
1. Identify the Drafts
The first step is pinpointing exactly where air is leaking into—or out of—your home.
Here’s how to find them:
✔ Wait for a windy day, then walk around your home with a lit candle or incense stick.
✔ Hold it near windows, doors, baseboards, and attic access points.
✔ If the flame flickers or the smoke wavers, you’ve likely found a draft.
✔ Feel for cool air around window frames or under doors—your hands can be a helpful tool.
In many homes, the most common areas for air leaks include older windows, poorly sealed exterior doors, and gaps around vents or wall penetrations.
2. Seal Windows with Caulk
Once you’ve identified which windows are leaking air, the next step is to seal them using weatherproof caulk.
Follow these steps:
✔ Apply caulk around the window frame, where it meets the exterior wall.
✔ Focus on any cracks, gaps, or spaces in the trim.
✔ Use clear or paintable caulk for aesthetic flexibility.
✔ For added insulation, use interior window insulation kits, which include plastic film that shrinks with a hairdryer to create a tight seal over the glass.
Properly sealed windows prevent heat from escaping in the winter and block hot air from entering in the summer, helping your HVAC system run more efficiently.
3. Use Weatherstripping on Doors
Doors are another major culprit when it comes to air leaks, especially around the edges and the bottom threshold.
Improve insulation by:
✔ Installing adhesive-backed weatherstripping around the door frame.
✔ Choosing from materials like foam, rubber, felt, or vinyl based on your needs.
✔ Adding a door sweep or draft stopper to seal the gap at the bottom of the door.
✔ Inspecting your garage door as well—especially if it’s connected to the house.
Proper weatherstripping can reduce drafts significantly and improve indoor temperature consistency throughout the home.
4. Add Insulated Curtains or Window Film
Sometimes, even well-sealed windows can still lose heat or allow solar gain due to the type of glass or lack of window treatments.
Enhance your insulation by:
✔ Installing thermal curtains or insulated drapes, which trap heat in the winter and block sunlight in the summer.
✔ Applying window film, which adds a thin, transparent barrier over the glass to reduce heat transfer.
✔ Using cellular shades, which have a honeycomb structure that acts as natural insulation.
These simple upgrades not only improve energy efficiency but also add a decorative touch to your home.
5. Schedule an HVAC Efficiency Check
Sealing up leaks is a great first step—but your HVAC system also needs to be in top shape to take full advantage of your efforts. Even a tightly sealed home can lose energy if your system is running inefficiently.
Consider the following:
✔ A professional HVAC tune-up will ensure your system is clean, calibrated, and operating at peak performance.
✔ Changing your air filters regularly can boost airflow and improve indoor air quality.
✔ Upgrading to a smart thermostat allows better temperature control and automatic adjustments when you’re away from home.
✔ Having your ductwork inspected and sealed can also eliminate energy loss from leaks in hidden areas.
Boost Efficiency with Marsh Heating & Air Conditioning
At Marsh Heating & Air Conditioning, we understand that comfort and efficiency go hand in hand. Sealing windows and doors is an important part of improving energy performance—but we also make sure your HVAC system is doing its part. Our team offers:
Professional system tune-ups and inspections
Installation of energy-efficient Lennox equipment
Smart thermostat upgrades
Air quality solutions to keep your indoor environment fresh and balanced
📞 Call Marsh Heating & Air Conditioning today at 763.536.0667 or visit MarshHeating.com to schedule your HVAC efficiency check and make your home more comfortable—no matter the season.
