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How HRVs save energy in Canadian homes
A Heat Recovery Ventilator brings fresh outdoor air into the home and exhausts stale indoor air, passing both airstreams through a heat exchanger core without mixing them. As warm stale exhaust air passes through, it transfers sensible heat to the cold incoming fresh air, preheating it before it reaches the furnace or enters the home's distribution system. This dramatically reduces the heating energy needed to condition ventilation air compared to passive infiltration or exhaust-only ventilation.
HRV sensible recovery efficiency is certified by HVI (Home Ventilating Institute) or under CSA standards at standardized test conditions, typically reported at both 0°C and -25°C since efficiency varies somewhat with temperature. Most residential cross-flow or counter-flow core HRVs achieve 60-80% sensible recovery efficiency. The preheated supply air temperature equals outdoor temperature plus efficiency times the temperature difference to indoor temperature.
Calculating annual energy savings
Annual energy savings from an HRV are calculated using heating degree days (HDD), a measure of how much and how long outdoor temperature stays below a base temperature (typically 18°C) over the year. The ventilation heating load avoided by heat recovery equals airflow times specific heat times HRV efficiency times HDD, converted to the appropriate energy units and divided by system efficiency (AFUE for gas, COP for heat pumps). This calculator applies Canadian climate data and current Canadian energy pricing to estimate realistic annual dollar savings for your specific city and heating system.
In a cold climate city like Winnipeg or Edmonton with 5,000+ heating degree days, the energy savings from a properly sized HRV running continuously are substantial — often paying back the incremental cost of the HRV system within a few heating seasons through reduced furnace runtime.
HRV vs ERV: which is right for your climate?
HRVs recover sensible heat only, leaving humidity unaffected. This is the standard choice for most of Canada, where winter air is already very dry and you don't want to recover and retain exhaust moisture that could promote condensation issues. ERVs (Energy Recovery Ventilators) also recover latent heat (moisture), which is more valuable in hot, humid summer climates where you want to keep humid outdoor air's moisture from entering. Use the ERV calculator to compare total energy recovery for climates with significant summer humidity loads, such as southern Ontario or the Maritimes.
Frequently Asked Questions
An HRV transfers heat from outgoing exhaust air to incoming fresh air through a heat exchanger core without mixing the airstreams. Exhaust-only ventilation simply expels indoor air and lets unconditioned outdoor air infiltrate, requiring the furnace to heat it from outdoor temperature all the way to room temperature. An HRV with 70% efficiency preheats incoming air partway, cutting heating energy for ventilation air by roughly 70%. At -20°C outdoor design temperature, this saves several hundred dollars per heating season for a typical Canadian home. Use the calculator above with your city's heating degree days for an exact estimate.
Start from the ASHRAE 62.2 requirement: Qfan = 0.03 × floor area (ft²) + 7.5 × (bedrooms+1) CFM. A 2,000 sq ft, 3-bedroom home needs about 90 CFM (42 L/s) continuous. Most residential HRVs are rated 100-200 CFM at 0.4 in. static pressure to allow margin for duct losses and boost mode. Size the HRV's rated airflow at your actual external static pressure, not the maximum free-air rating. Use the ventilation rate calculator to get your exact requirement first.