When planning for winter, look for projects that will reduce home heating costs. Insulation is usually the first thought, while air sealing is a close second. Two critical areas of the home to insulate are the attic and basement. Each area lends itself to a different type of insulation product.

Attic Insulation

Before adding any insulation, check the attic for air leakage. Warm air from inside the house can leak directly into the attic around recessed light fixtures, exhaust fans, the attic hatch, and penetrations like vent stacks. The warm air can condense on the cold underside of the roof, which can lead to wood deterioration.

Foam lining the inside of an electrical receptacle

Check for Indirect Air Leaks via Wall Openings

Common culprits include electrical receptacles and around baseboards. Foam gaskets can be used to cover electrical receptacle plates. Acrylic latex sealants or urethane foam can be used to seal other leakage openings into the attic.

Gloved hand applying foam insulation around an attic entryway

Seal & Insulate with Foam Insulation

Use small cans of one-component spray foam for most insulating/sealing jobs around the house. For bigger projects, like sealing and insulating the spaces between the second floor joists in a storey-and-a-half house (a major source of air leakage), use large froth-paks of two-component foam.

Metal tube on the ceiling of a room

Keep the Soffit Clear of Insulation

Air circulation from the soffit is necessary in removing any humid air that might still escape into the attic. Install vents between the rafters so the required air space is maintained, and make sure the soffit itself is actually vented instead of installing vented aluminum soffit panels directly on solid, unventilated wood soffits.

Insulation surrounding a pot light

Avoid Directly Insulating Recessed Potlight Fixtures

Unless specifically designed for such use, don't directly insulate recessed potlight fixtures. Doing so can cause heat to build up, which can create a potential fire hazard. The construction of an airtight drywall box around the fixture is a good way of allowing heat from the potlight to dissipate.

Basement Insulation

For basements, rigid or semi-rigid insulation is the most appropriate. There are two options when insulating a basement wall: inside and outside. Outside is usually the best option, as it allows you to address water penetration issues, such as installing drainage tile, repairing wall cracks, and applying waterproofing or damproofing.

Drainage layer lining the base of a brick wall

Add a Filtered Drainage Layer

A filtered drainage layer is especially useful in fine-grained soils where water can run through faster than normal. A filter cloth, during the service life of the building, can prevent fine soil particles from accumulating behind the drainage layer, which reduces the chances of water leaking into the basement.

Person

Plan for Basement Wall Condensation with Interior Insulation

Exterior insulation is the better approach, as interior insulation can cause condensation on the basement wall. To prevent studs and strapping from deteriorating, keep them away from direct contact with the basement walls by installing extruded polystyrene insulation to the back of studs, or even to the entire wall. You can also keep the bottom plate off the basement floor and keep the drywall about 50 millimetres off the floor.

Man checking insulation in basement wood framing

Avoid Insulating in Frost-Susceptible Soil

When it comes to the interior of a block basement wall, don't insulate it in frost-susceptible soil, like silt. Interior insulation will cause the block's exterior to be cold, and adfreezing (soil frost adhering to the block's exterior) can occur. The combination of frost heave and adfreezing may cause the blocks to displace.

Finished basement with overstuffed leather chairs and brick fireplace

Take Comfort into Account

When it comes to insulating and air sealing projects, think of more than just cost savings to justify the expense. Having quality insulation and air sealing in place also means many years of comfort ahead of you.

Quick & Easy Winterization Tips

Here are some simple maintenance projects you can do yourself. They require minimal effort and utilize tools you likely already have at home.

  • Programmable thermostat on a wall with a light coloured living room in the background

    Install a Programmable Thermostat

    A programmable thermostat lowers the furnace setpoint when additional heat isn't needed, such as when asleep or away at work. Different models allow for a seven-day per-week scheduling, weekday/weekend scheduling, and even multiple cycles within a day.

    SHOP PROGRAMMABLE THERMOSTATS
  • Man on a ladder cleaning his gutters

    Clean Gutters

    Removing leaves and other debris from the gutters helps ensure that water will drain freely in the eaves.

    SHOP GUTTER GUARDS
  • Package of electric snow melting cables

    Install Snow-Melting Cables

    Using electric cables on the roof will help prevent ice damming.

    SHOP ELECTRIC ROOF CABLES
  • Person vacuuming a furnace filter

    Change or Wash Furnace Filters

    A clean furnace filter not only removes particulates from the air better than a clogged, dirty one, it also improves furnace performance by providing less resistance to airflow. While High Efficiency Particulate Air (HEPA) filters are the most effective, they also provide the most resistance to airflow and can compromise a furnace's performance not designed for HEPA use.

    SHOP FURNACE FILTERS
  • Wood ceiling fan in a room

    Reverse the Direction of Ceiling Fans

    Cooler air tends to sink while warmer air rises, as cooler air is denser than warmer air. In the summer, ceiling fans should be set to push air downwards, creating a cooling draft. In the winter, set the ceiling fan to circulate air upwards to avoid the cooling draft (as well as gently mix the warm air with the cool air for a more uniform room temperature).

    SHOP CEILING FANS

Don't Forget the Windows & Doors

Since up to 25 percent of heat energy in a house can be lost through windows and doors, winterizing them can help save energy.

  • Upper corner of a door showing what the frame looks like on the inside

    Winterize Windows & Doors to Reduce Lost Heat Energy

    Techniques like adjusting or replacing hardware and adjusting sash back to square are simple improvements you can do to reduce air leakage.

    SHOP WINDOW & DOOR HARDWARE
  • Brush weather stripping for a door

    Replace Weather Stripping & Door Sweeps

    It can be impossible to find exact replacements, so try to replace like with like (e.g. replace compression gaskets with compression gaskets, etc.) and don't worry if the new part doesn't install in the kerf like the original. You can simply secure weather stripping to the face of the kerf or side of the jambs instead.

    SHOP WEATHER STRIPPING
  • A hand spraying foam insulation between a door and its frame

    Seal & Insulate Window & Door Perimeters

    Try to remove the interior trim and insulation in the gap between the studs before spraying a low-expanding one-component polyurethane window and door foam (make two passes). The first pass should be tight against the outside trim or trick mold and no more than 25 millimetres deep. Let the foam dry completely. The second pass should also be no more than 25 mm. deep, but inside of the gap so there's an air space between the layers.

    If you can't remove the interior trim, apply an acrylic latex sealant around the casing's perimeter instead.

    SHOP WINDOW & DOOR INSULATION

Other Ways to Winterize Windows


  • Install solar window film to help reflect some of the heat back into the house.
  • Install shrink wrap to the window frame to create a still air space that improves the heat flow resistance of the window.
  • Replace leaky windows — a particularly cost-effective strategy if the windows are single-glazed.
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