Canadian winters impose a wide range of stresses on residential buildings — from below-freezing temperatures in southern Ontario to extreme cold snaps in Prairie provinces. A home that isn't prepared before November typically accumulates problems that compound into costly repairs by spring. This guide works through the main systems of a house in a logical order, so nothing gets skipped.
Attic and Roof
Heat loss through an inadequately insulated attic is one of the single largest sources of wasted energy in Canadian homes. The Natural Resources Canada guide on attic insulation recommends a minimum of RSI-8.6 (R-49) for most of Canada outside of the warmest coastal regions.
Before insulating, check the attic ventilation. Proper soffit-to-ridge airflow prevents moisture accumulation, which leads to mould and premature sheathing rot. Blocked baffles — a common issue in homes where insulation has shifted — should be cleared and reinstalled before adding any new material.
Roof Inspection Points
- Look for missing, curled, or cracked shingles — these allow ice and water to infiltrate decking
- Check flashing around chimneys, skylights, and vents for gaps or rust
- Clear gutters completely — ice dams form when melting snow refreezes in clogged gutters and backs up under shingles
- Ensure downspouts direct water at least 1.8 m away from the foundation
Windows and Doors
A single-pane window has roughly RSI-0.18 (R-1) insulating value. Even a double-pane unit with air fill sits around RSI-0.35. The thermal difference between a well-sealed double-pane and a drafty single-pane matters significantly when outdoor temperatures reach −25 °C.
In the short term, rope caulk — a temporary, removable sealant — applied to leaking window frames at the start of each season costs under $10 per window and eliminates a measurable amount of heat loss. It pulls off cleanly in spring.
Door weatherstripping degrades over three to five years of regular use. The standard test: hold a dollar bill in the closed door gap. If it pulls out without resistance, the seal is inadequate. Replace the weatherstripping with EPDM rubber rather than foam, which compresses and loses effectiveness faster.
What to Check on Each Exterior Door
- Door sweep — no light visible beneath the door when closed
- Weatherstripping along the frame — no compression gaps
- Lock alignment — if the bolt is stiff, the frame has shifted from summer humidity and needs adjustment
- Threshold seal — a draughty threshold on a steel door accounts for a surprising amount of heat loss
Heating System
A forced-air furnace should be inspected and cleaned by a licensed HVAC technician at least once a year — ideally in September before the heating season begins. A tune-up typically costs $100–$180 in Canadian markets and verifies heat exchanger integrity, combustion efficiency, and carbon monoxide safety.
Furnace filters should be changed monthly during peak heating season in homes with pets or high dust levels, and at minimum every three months otherwise. A clogged filter reduces airflow, making the furnace run longer and increasing wear on the blower motor.
Supplemental and Alternative Heating
- Wood stove or fireplace: Annual WETT inspection is required for most home insurance policies in Canada
- Electric baseboards: Dust accumulation reduces efficiency — vacuum the fins before first seasonal use
- Heat pump systems: Ensure the outdoor unit is not obstructed and the refrigerant charge is current
- Propane or oil systems: Check tank levels and confirm delivery schedule before November
Exterior and Landscape
Outdoor tasks are best completed in mid-October in most of Canada, before the ground freezes. Detach and drain garden hoses — a hose left connected traps water in the exterior shutoff valve, which can split the valve body when temperatures drop.
Exterior Task Order
- Disconnect all garden hoses and store indoors
- Shut off exterior tap valves from inside the basement and open the outdoor tap to drain remaining water
- Inspect the foundation perimeter for cracks wider than 3 mm
- Grade soil away from the foundation if it has settled inward — water pooling against the foundation accelerates freeze-thaw damage
- Drain and winterize irrigation systems (blow-out method with compressed air)
- Cover or store patio furniture, gas grills, and garden equipment
- Remove dead annuals and turn compost before the ground freezes solid
Garage and Outbuildings
An attached garage is often the weakest thermal boundary in a home. Cold air infiltrates through the door-to-house passage, garage door gaps, and uninsulated walls. If the garage shares a wall with living space, insulating that wall to at least RSI-2.1 (R-12) and weatherstripping the entry door makes a noticeable difference in heating costs.
Detached garages used as workshops benefit from a low-wattage electric heater on a thermostat set to 2 °C — enough to prevent damage to stored fluids, tools, and any plumbing lines running through the structure.
Carbon Monoxide and Smoke Detectors
Heating-related carbon monoxide incidents spike in winter. Ontario, British Columbia, and several other provinces legally require CO detectors in homes with attached garages or fuel-burning appliances. A detector should be installed on each floor and within 5 metres of every sleeping area. Replace units every 7 years — the electrochemical sensing cells degrade over time regardless of whether an alarm has triggered.