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Person draftproofing the window.

Seal up gaps and cracks to reduce drafts and save

Gaps and cracks around windows and doors can let cold air in during the winter months and warm air in during the summer months. This causes your heating and cooling systems to have to work harder, increasing your home's energy use.

Draftproofing – also known as weather stripping – is one of the simplest and most affordable ways to improve your home's energy efficiency.

On this page:

First, check for drafts around windows and doors

Here are four ways to help identify drafts around windows and doors:

  1. Use a thermal detector: Point the detector anywhere you suspect heat could be escaping or getting in. If you see a 5°C or more change in either direction, you know you have a leaky spot.
  2. DIY smoke test: On a cool and windy day, light a stick of incense and hold it up close to the areas you suspect air might be leaking. If the smoke moves back and forth, or if it's blown out, there's a leak.
  3. Noise check: Open the window or door a fraction and listen to the noise level coming from outside, then close the window or door. If you can still hear the outside noise clearly, there's a draft. A good seal would cut out most of the noise.
  4. Blower door test: If you want a professional assessment, energy auditors can come in and use a powerful fan to evaluate the overall air tightness of your home.
Dave demonstrates how to use a thermal detector to check for drafts around your home’s windows and doors. This video was filmed during the summer but the same draft checks can be done during the colder winter months.

Once you've identified any drafts in your home, follow the tips below to learn how to apply simple draftproofing to seal up those gaps and cracks.

How to apply draftproofing

V-seal weather stripping is great for sliding windows, and foam weather stripping is a champion inside door frames.

Pick up your supplies

If this is your first time attempting DIY fixes around your home, you might be wondering where to get draftproofing supplies. Most home hardware stores carry V-seal and foam weather stripping, as well as foam insulator pads for your outlets and light switches that are on external walls.

Instructions for foam weather stripping

Foam weather stripping creates a barrier against drafts around doors and windows. It's applied to the part of the frame that touches the exterior side of your door or window.


  • Foam weather stripping
  • Measuring tape


  1. Once you've identified the area you want to seal, make sure it's nice and clean before you start.
  2. Measure out the length of the area you’re looking to seal. For example, if you’re sealing around your door, measure the door from top to bottom.
  3. Cut your foam weather stripping to measured length and peel off the plastic from the adhesive side.
  4. Stick the adhesive side of the foam weather stripping to the area you want to seal. Double-check that the adhesive is applied properly all the way from the top to the bottom.

Instructions for V-seal weather stripping

V-seal weather stripping is made from plastic and is folded into a "V" shape that opens up to fill gaps. Use this for areas such as double-hung or sliding windows and on the top and sides of doors.


  • V-seal weather stripping
  • Measuring tape


  1. Start by measuring the length of the window or door before you cut the v-seal.
  2. Fold the v-seal in a line down the middle, creating a v-shape with the adhesive side on the outside.
  3. Peel off the protective backing as you apply the strip, then press into place.
  4. Close the door or window to check that the strip compresses slightly for a snug fit.
Dave shows how to apply foam and V-seal weather stripping to reduce drafts in your home.

A draftproofing don't

When sealing cracks and gaps around windows and doors, make sure that you do so in a way that still allows you to open and close them as needed. Don't apply caulking or double-sided tape as a quick fix for draftproofing in a way that will seal your windows and doors shut.

Checklist: common spots to draftproof

Here are five of the most common heat-escaping spots in your home to seal up.

  • Window and door frames – These are prime spots for cool air to creep in. Luckily, foam and v-seal weather stripping are your draftproofing heroes.
  • Bottom of exterior doors – There’s often a gap that lets drafts and noise through. A door sweep is an inexpensive way to block the cool air that can seep in. You can find door sweeps at most major home renovation stores for as little as $9.
  • Light switches and electrical outlets – On exterior walls, these are sneaky spots for heat loss. Get little foam gaskets that fill the space to stop the draft. They cost as little as $1 each.
  • Window panes – If you have older, single pane windows, window insulating film is a great solution for you.
  • Air ducts, vents, pipes and cables – Take a look at where air ducts, vents, pipes and cables enter or exit your home and use caulk or spray foam to fill the gap for a tight, draft-blocking seal.

Insulate outlets and light switches

Outlets and light switches in the walls that separate your home from the outdoors can be a source of heat loss. Insulating these areas using pre-cut foam insulator pads (also known as foam gaskets) can help reduce drafts.


  • Screwdriver
  • Foam outlet gasket
  • Foam light switch sealer


  1. Turn off the electricity at the circuit breaker before you start.
  2. Remove the cover plate from your outlet or switch with a screwdriver that matches the plate screws.
  3. Choose a foam pad with pre-cut holes that match the job.
  4. Remove the extra material from the holes, then place the pad over the outlet or switch.
  5. Put the cover plate over the foam pad and re-attach it to the wall with your screwdriver.
  6. Insert safety caps on any unused outlets.
Watch Dave explain how to make your baseboard heating more efficient.