Blower door testing in Delta

Delta gets about 2,768 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 −4.4°C. Those figures come from the climate data for Vancouver International in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. That's the 4th-lowest heating demand of the 70 cities we cover. Mild, wet winters: heating bills are modest, so moisture control and comfort matter as much as cutting heat loss.

Leaks also let damp air into walls and attics, so the coast's wet winters are a reason to find them before adding insulation. Delta also gets hot spells and heat waves, so plan how the house will stay cool: air sealing, attic insulation and shading help, and a heat pump adds efficient cooling. Wildfire smoke reaches Delta in some summers. The Government of Canada's advice is to keep windows and doors closed, limit exhaust fans and use the best filter your system can handle, so ask the advisor what your furnace or HRV can take.

Of Delta's 31,845 houses (single-detached, semi-detached, row houses and duplexes), 8% were built before 1961 and 74% 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.

• Combustion safety. In the Vancouver area, the main heating energy is natural gas for 42% 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 Delta
• Radon. Sealing shifts the pressure balance between the house and the soil. In Health Canada's 2012 survey, none of the 69 homes tested in the Fraser South Health Service Delivery Area health region were above the guideline, a small sample that doesn't rule radon out. The larger 2024 Cross-Canada survey reports 0.9% (1 in 113) of houses at or above the guideline for Vancouver Metro Area (Vancouver CMA). Test before and after big air-sealing jobs. Radon testing in Delta

A blower door test is part of every EnerGuide evaluation rather than a separate purchase. There's no provincial price list; the City of Nanaimo quotes $400–$500 as typical for an existing home. Several B.C. municipalities subsidize evaluations for their residents (see local programs below).

• 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.

The blower door test in detail.