How Sherbrooke is built
- Before 1961 18%
- 1961–1990 42%
- 1991–2000 13%
- 2001 or later 27%
Why air leakage matters in Sherbrooke
Sherbrooke gets about 4,517 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 −25.8°C. Those figures come from the climate data for Lennoxville in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. That's about 15% 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.
Sherbrooke summers are hot and humid, so the air sealing and insulation that cut heating bills also keep the house cooler, and a heat pump can do the cooling more efficiently than an old air conditioner.
Of Sherbrooke's 41,360 houses (single-detached, semi-detached, row houses and duplexes), 18% were built before 1961 and 60% 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
- Radon. Sealing shifts the pressure balance between the house and the soil. Health Canada's 2012 survey found 9.3% of 54 homes tested in the Région de l'Estrie health region above the guideline. The larger 2024 Cross-Canada survey reports 24.9% (1 in 4) of houses at or above the guideline for the Sherbrooke, QC (Sherbrooke CMA) metro area. Test before and after big air-sealing jobs. Radon testing in Sherbrooke
What it costs in Sherbrooke
A blower door test is part of every EnerGuide evaluation rather than a separate purchase. In Quebec, EnerGuide evaluations are booked through the provincial Rénoclimat program: the pre-retrofit evaluation costs $150 plus taxes, reimbursed when you receive financial assistance under the program, and the first post-retrofit evaluation is free.
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.
Great Lakes–St. Lawrence Southern Ontario and southern Quebec
What this means in Sherbrooke’s climate
Cold winters and hot, humid summers: seal the attic, dry the basement, plan cooling.
Why it matters here: Measures leakage (ACH50) and, with a thermal scan, finds where air gets in.
Best timing: Any season; pair it with a thermal scan in winter.
- Seal air leaks and top up the attic. Air sealing is still the first retrofit. In the snowier Ottawa–Montreal–Sherbrooke belt, a leaky, under-insulated attic also causes ice dams. Ask: Ask for a blower door test and attic inspection, and whether old vermiculite insulation needs testing before any attic work.
What else homes in Sherbrooke 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)
- Air-Source Heat Pump Sizing and Selection Guide (NRCan)
- Heating and Cooling With a Heat Pump (NRCan)
- Heat pump basics (NRCan)
- Gas and heat pump hybrid systems (NRCan)
- Primary heating systems by household, Table 38-10-0286-01 (Statistics Canada)
- Electricity price comparison, April 2025 (Hydro-Québec)
- Canada's top weather stories of 2018 (ECCC)
- Canada's top weather stories of 2022 (ECCC)
- Canada's top weather stories of 2023 (ECCC)
- Canada's most impactful weather stories of 2024 (ECCC)
- Canada's top weather stories of 2025 (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 2019 (ECCC)
NRCan-licensed service organizations serving Sherbrooke
In Quebec, EnerGuide evaluations for existing homes run through the provincial Rénoclimat program; the organizations below are the ones NRCan lists for Sherbrooke postal codes.
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 Sherbrooke. Ask to walk the house with the advisor while the fan runs.
- ENERGIE3R
- Expertbâtiment Services-Conseils
- Les Services ecoPlus
Blower door test in Sherbrooke: common questions
Where can I get a blower door test in Sherbrooke?
Book an EnerGuide evaluation with any of the 3 NRCan-licensed organizations serving Sherbrooke; the blower door test is part of every evaluation.
How much does a blower door test cost in Sherbrooke?
It is included in an EnerGuide evaluation. In Quebec, EnerGuide evaluations are booked through the provincial Rénoclimat program: the pre-retrofit evaluation costs $150 plus taxes, reimbursed when you receive financial assistance under the program, and the first post-retrofit evaluation is free.
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.