What is the difference between an ERV and an HRV for a Toronto home?

The core difference is simple: an HRV (Heat Recovery Ventilator) transfers only heat between incoming and outgoing airstreams, while an ERV (Energy Recovery Ventilator) transfers both heat and moisture. This single distinction has significant practical implications for comfort, energy costs, and indoor air quality in a GTA home across all four seasons.

Both units perform the same basic function — they bring fresh outdoor air into the home and exhaust stale indoor air, using a heat exchanger core to recover energy from the outgoing air before it leaves. A modern unit recovers 70 to 85 percent of the thermal energy, meaning that in January when it is minus 15 degrees Celsius outside and 21 degrees inside, the incoming fresh air arrives pre-warmed to roughly 10 to 15 degrees rather than hitting your furnace at minus 15. This saves substantial energy compared to simply opening a window.

Where they differ is moisture handling. An HRV's core (typically aluminum or plastic plates) transfers heat but allows moisture to pass through unchanged. In winter, dry outdoor air enters the home at its original low humidity, and the moist indoor air is exhausted, taking its moisture with it. This means an HRV tends to dry out the home in winter — helpful if you have condensation problems on windows, but potentially uncomfortable if your indoor air is already too dry. In summer, an HRV brings in outdoor air at Toronto's full outdoor humidity — often humidex values above 40 — dumping that moisture load onto your air conditioning system.

An ERV's core (typically a polymer membrane or treated paper) transfers both heat and moisture. In winter, the core retains a portion of the moisture from the outgoing air and transfers it to the dry incoming air, helping maintain indoor humidity in the comfortable 30 to 40 percent range without over-relying on a humidifier. In summer, the core strips moisture from the incoming humid outdoor air before it enters the home, reducing the dehumidification load on the air conditioning system. For an air-conditioned Toronto home, this moisture transfer can reduce cooling energy consumption by 5 to 15 percent during the humid months of June through September.

Which Is Right for Your GTA Home?

Choose an ERV if your home has central air conditioning (the vast majority of GTA homes), you want to maintain comfortable humidity levels year-round without excessive humidifier or dehumidifier use, or you are building new and want the most versatile system. An ERV costs $3,000 to $6,000 installed with dedicated ductwork.

Choose an HRV if your home does not have air conditioning and you primarily need winter ventilation, you have persistent condensation problems on windows that indicate excess indoor humidity, or your budget is tighter. An HRV costs $2,500 to $5,000 installed with dedicated ductwork.

Both systems require dedicated ductwork with supply points in bedrooms and living areas and exhaust points in bathrooms, kitchens, and laundry rooms. Both need annual filter cleaning and core washing, and both require professional balancing at installation to ensure equal supply and exhaust airflows. The Ontario Building Code requires mechanical ventilation in new homes and significantly air-sealed existing homes, and either an ERV or HRV meets this requirement.

If you are unsure which system suits your home, a ventilation assessment by a qualified HVAC contractor will determine the right choice based on your home's air-sealing level, cooling system, and humidity patterns. Toronto Ductwork can connect you with ventilation specialists across the GTA through the Toronto Construction Network.