Should I install an ERV or HRV in my Toronto home for fresh air ventilation?

For most Toronto homes with central air conditioning, an ERV (Energy Recovery Ventilator) is the better choice because it manages both heat and moisture transfer — a significant advantage during the GTA's humid summers. If your home does not have air conditioning and you primarily need ventilation for winter moisture control, an HRV (Heat Recovery Ventilator) is the more appropriate and less expensive option.

Both ERVs and HRVs bring fresh outdoor air into your home while exhausting stale indoor air, passing the two airstreams through a heat exchanger core that recovers 70 to 85 percent of the energy from the outgoing air. The critical difference is that an ERV's core transfers both heat and moisture, while an HRV's core transfers only heat. In practical terms for a GTA homeowner, this means an ERV prevents hot, humid outdoor air from dumping its moisture load into your air-conditioned home during July and August — the ERV's core strips some of that humidity out before the air enters the house. An HRV would bring in outdoor air at full outdoor humidity, adding to your air conditioning and dehumidification load.

Conversely, during Toronto's dry winter months when indoor humidity drops to uncomfortable levels, an ERV retains some of the moisture from the outgoing air and returns it to the incoming air, helping maintain indoor humidity in the healthy 30 to 40 percent range. An HRV exhausts all that moisture, potentially making already-dry winter air even drier and forcing homeowners to run a humidifier harder.

The Ontario Building Code requires mechanical ventilation in new homes and any home that has been significantly air-sealed through energy retrofits. The minimum ventilation rate for a typical three-bedroom GTA home is approximately 50 to 70 CFM of continuous ventilation. Both ERVs and HRVs meet this requirement when properly sized and installed. The choice between them comes down to your home's cooling and humidity profile.

Cost and Installation

An HRV installed with dedicated ductwork costs $2,500 to $5,000 in the GTA market. An ERV installed with dedicated ductwork costs $3,000 to $6,000. The $500 to $1,000 premium for an ERV is easily justified in an air-conditioned home by reduced humidity load on the cooling system and improved comfort. If you already have an HRV or ERV and the existing ductwork is in good condition, a replacement unit costs $1,500 to $3,500 installed.

The unit should have its own dedicated ductwork — supply air to bedrooms and living areas, exhaust air from bathrooms, kitchen, and laundry. Do not simply connect an ERV or HRV to your existing furnace duct system without proper design, as this creates balancing issues and may not provide adequate ventilation to all rooms. The system should be balanced so that supply and exhaust airflows are within 10 percent of each other, and the controls should allow for boost mode during cooking or showering.

For the vast majority of GTA homeowners with central air conditioning — which is nearly everyone in the current market — an ERV is the recommended choice. The humidity management alone pays for the modest price premium within a few summers. If you need help finding a ventilation specialist, Toronto Ductwork can match you with experienced installers through the Toronto Construction Network.