How St. John's is built
- Before 1961 22%
- 1961–1990 42%
- 1991–2000 11%
- 2001 or later 26%
Why air leakage matters in St. John's
St. John's gets about 4,578 heating degree-days a year, a measure of how much heating its climate needs, and its winter design temperature, the cold day heating systems are sized for, is −12.8°C. Those figures come from the climate data for St-John's International in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. That's about 16% more heating demand than the middle of the 70 cities we cover. A long heating season: air sealing and insulation pay back well, and every leak costs money for months.
Of St. John's's 42,120 houses (single-detached, semi-detached, row houses and duplexes), 22% were built before 1961 and 64% before 1991, according to the 2021 Census. Older houses usually test leakier than newer ones, and an EnerGuide report compares your result with homes of the same era, so you can see whether your house is typical or a problem.
After you seal: two checks
- Combustion safety. In the St. John's area, the main heating energy is oil for 12% of households. A tighter house changes how fuel-burning appliances vent, so the spillage check should be repeated after serious air sealing. Combustion safety testing in St. John's
- Radon. Sealing shifts the pressure balance between the house and the soil. Health Canada's 2012 survey found 4% of 100 homes tested in the Eastern Regional Integrated Health Authority health region above the guideline. In the City of St. John's free test-kit program, about 345 kits went out in November 2024 and 278 homes completed testing over the winter; about one in ten of them were above Health Canada's 200 Bq/m³ guideline. The participants were volunteers, so it isn't a random survey. Test before and after big air-sealing jobs. Radon testing in St. John's
What it costs in St. John's
A blower door test is part of every EnerGuide evaluation rather than a separate purchase. There's no province-wide price; takeCHARGE lists the service organizations working in the province without prices.
How the test works
- A calibrated fan is fitted into an exterior door and pulls air out until the house is at 50 pascals, the standard test pressure.
- The result is air changes per hour at 50 Pa (ACH50): how many times an hour the whole volume of air would leak out and be replaced at that pressure.
- While the fan runs, you and the advisor walk the house and feel for leaks at the attic hatch, rim joists, pot lights, trim and plumbing and wiring penetrations.
- A second test after the work shows what changed, and it is what most rebates pay on.
Atlantic Canada Maritimes and Newfoundland
What this means in St. John's’s climate
Damp, windy, icy winters and costly oil: switch to heat pumps, seal, test for radon.
Why it matters here: Finds wind-driven leakage paths; a before-and-after test shows what sealing achieved.
Best timing: December to March, on a calm day.
- Seal wind-driven leaks and the attic. Wind pushes cold air through gaps, and heavy, wet snow with frequent freezing rain makes a leaky attic prone to ice dams. Ask: Ask for a blower door test on a calm day, with a thermal scan to find wind-driven leaks.
What else homes in St. John's need →
Sources for this climate guide · checked October 26, 2026
- National Building Code of Canada 2020, climate data (NRC)
- Canadian Climate Normals 1991–2020 (ECCC)
- Keeping the Heat In (NRCan)
- Heat pumps, Canada Greener Homes (NRCan)
- Heat pump basics (NRCan)
- Heating and Cooling With a Heat Pump (NRCan)
- Primary heating systems by household, Table 38-10-0286-01 (Statistics Canada)
- Household heating oil prices, Table 18-10-0001-01 (Statistics Canada)
- Electricity price comparison, April 2025 (Hydro-Québec)
- Prevent oil tank spills (Government of Nova Scotia)
- Canada's top weather stories of 2019 (ECCC)
- Canada's top weather stories of 2022 (ECCC)
- Canada's top weather stories of 2023 (ECCC)
- 2024 Cross-Canada Survey of Radon Exposure
- Guide for Radon Measurements in Homes (Health Canada)
- Conditions for thermal scans, ASTM C1060 summary (Cx Associates)
- Canada's top weather stories of 2020 (ECCC)
- Canada's top weather stories of 2021 (ECCC)
NRCan-licensed service organizations serving St. John's
A service organization is a company that Natural Resources Canada (NRCan) licenses to deliver EnerGuide evaluations; its registered energy advisors do the home visit. A blower door test is part of every EnerGuide evaluation, so any organization below can do one in St. John's. Ask to walk the house with the advisor while the fan runs.
- AmeriSpec Profile
- Canada Energy Audit Profile
- CLEAResult
- Homesol Building Solutions
- Sustainable Housing and Education Consultants Incorporated
- ThermalWise Green Building Cooperative
- Ecostep Energy Services
Programs that include a blower door test in St. John's
Blower door test in St. John's: common questions
Where can I get a blower door test in St. John's?
Book an EnerGuide evaluation with any of the 7 NRCan-licensed organizations serving St. John's; the blower door test is part of every evaluation.
How much does a blower door test cost in St. John's?
It is included in an EnerGuide evaluation. There's no province-wide price; takeCHARGE lists the service organizations working in the province without prices.
What is a good blower door result?
Lower is better. Your EnerGuide report compares your air changes per hour at 50 Pa with homes of the same era, which is more useful than a single target number.
Does air sealing affect radon?
It can. Tightening a house changes the pressure difference with the soil, so test for radon before and after major air sealing.