In addition to the tips below, visit myEnergy Marketplace for additional information on what to look for in energy-efficient products, as well as cost-saving rebates.

Up to 25% of your home heating costs may be attributed to leaking through doors, windows, outlets and vents. Proper air sealing and insulation can reduce energy use, make your home more comfortable year-round and lower your carbon footprint.

4 signs you may need more insulation and air sealing

1 Unusually high heating and cooling bills
2 Cold floors and walls in the winter
3 Drafty rooms
4 Mould on walls or in the basement

How much insulation do you need?


Insulation is rated with an R-value, and the amount your home needs depends on the climate zone you live in. Higher levels of R-value in your insulation will help reduce your energy loss. Most homes in northern Ontario are in Zone 3, and need more insulation than homes in Zone 2. For more information on how to prevent heat loss in your home, visit the ENERGY STAR® Energy Savings at Home section.

Map of Ontario zones

How to stop air leaks


The first step is to detect where air is escaping. Then, a thorough job of caulking, weatherstripping and insulating can help reduce your heating and cooling costs significantly.

Start with this simple test: on a windy day, light a stick of incense and move it slowly around windows, doors, and where walls meet the floor and ceiling. If the smoke flutters, you may have a leak. Spider webs can also be a sign of air leaks.

Top spots for air leaks

Air leakage breakdown in the average home:

Floors, walls and ceiling
Ducts 15%
Fireplaces 14%
Plumbing penetrations 14%
Windows 10%
Fans and vents 4%
Electrical outlets 2%

Invest to improve

Start with the attic, basement and exterior walls, then move to windows and doors. For some projects, you may need to hire a qualified contractor. Be sure to get at least three quotes to compare, check references and ask about installation options and warranties.
  • 1

  • Attic
    • Seal around the attic hatch, plumbing stack vent and any recessed lights.

    • Add insulation over ceiling joists.

  • 2

  • Basement
    • Seal around your dryer vent and outdoor faucet.

    • Seal around the sill plate (a large source of air leaks). Use butyl rubber caulking or an acoustical sealant to fill gaps. If the joists rest on the wooden sill, caulk around the joists, too.

  • 3

  • Walls
    • Seal around your kitchen fan vent.

    • Seal around the exterior top plate.

    • Insulating interior walls is easiest when you are doing major renovations; once you have the drywall or plaster off, you can lay insulation between wall studs and joists.

  • 4

  • Windows and doors
    • Consider replacing single pane windows and uninsulated doors with more energy-efficient models. Talk to a contractor about your buying options.

    • Check windows for rot, mould, glass condition, putty and paint. If they are beyond repair, consider high-efficiency replacements.

    • If they are in good condition, check the trim. If you can easily remove it, stuff insulation between the window and your home’s frame. If it does not come off easily, caulk around it.

    • Check out our Guide to Window Savings to find out how& you can& save energy by upgrading to ENERGY STAR® certified windows, plus no-cost and low cost DIY energy saving tips.

More low-cost, no-cost tips

Close Your Damper
Close Your Damper

No fire burning? That open flue damper sucks warm air out of your home. If you no longer burn wood, consider sealing it.


Don't forget your home's exterior! Make sure to use insulated electrical outlet boxes with proper sealing to prevent air leaks.

Clean the Tracks
Clean the Tracks

Remove dust and debris from the track on your sliding glass door to ensure it keeps air in.

Add a Skirt

A properly fitted door closes firmly and does not allow air to leak in on the sides, top or bottom. For a few dollars you can buy rubber weatherstripping to skirt the doorframe.

Add a Skirt

Shopping tips

Caulking comes in a wide variety of colours and applications. Use this handy buying checklist to help choose the right type for the job.
  • Is it for use indoors, outdoors or both?

  • Is it the right colour?

  • Is it paintable?

  • What surfaces will it adhere to?

  • What size gap will it seal?

  • What preparation is required?

  • How long will it last?

  • How much does it cost?

  • What is the recommended temperature for application?

Remember! Always ventilate properly when caulking to let fumes escape.