HRV vs ERV in Ontario: Which Ventilation System Does Your Home Need?

What Do HRVs and ERVs Actually Do?

Both HRVs and ERVs solve the same fundamental problem: modern homes are built (or renovated) to be airtight for energy efficiency, but people still need fresh air. Opening windows works in summer, but for the five to six months of Ontario winter, you need a mechanical system that brings in fresh air without wasting the heat you have already paid for.[2]

Heat Recovery Ventilator (HRV)

An HRV continuously exchanges stale indoor air for fresh outdoor air. As the two air streams pass through a heat exchange core (without mixing), the outgoing warm air transfers its heat to the incoming cold air. A good HRV recovers 70-85% of the heat energy, meaning incoming air at -10°C might be warmed to 10-15°C before entering your living space.[1]

HRVs transfer heat only, not moisture. In Ontario's dry winters, this is actually beneficial: by exhausting moisture-laden indoor air and replacing it with dry outdoor air, an HRV helps prevent condensation on windows and moisture buildup in walls and attics.

Energy Recovery Ventilator (ERV)

An ERV works on the same principle as an HRV, but its exchange core also transfers moisture between the air streams. In winter, this means some of the humidity from the outgoing air is returned to the incoming air, helping maintain indoor humidity levels. In summer, it works in reverse, removing some humidity from incoming outdoor air before it enters your home.[1]

HRV vs ERV: Head-to-Head Comparison

Which One Is Right for Ontario?

For most Ontario homes, an HRV is the better choice. Here is why:

Ontario's Climate Favours HRVs

Ontario sits in ASHRAE climate zones 5A (southern Ontario, including the GTA) and 6A (northern Ontario). The dominant challenge is cold, dry winters that last five to six months. During this period, homes generate significant moisture from cooking, bathing, and breathing. An HRV exhausts this excess moisture along with stale air, which helps prevent:

• Condensation on windows (a common Ontario winter complaint)
• Moisture accumulation in walls, attics, and crawl spaces
• Mould growth from trapped humidity

An ERV would retain some of that indoor moisture rather than exhausting it, which in Ontario's winter climate can contribute to the very condensation problems you are trying to solve.

When an ERV Makes More Sense

There are situations where an ERV is the better choice, even in Ontario:

• Homes with very dry indoor air: If you already struggle with excessively dry air in winter (cracking wood floors, static electricity, respiratory discomfort) and use humidifiers regularly, an ERV can help retain some moisture.
• Homes with significant summer cooling loads: An ERV can pre-dehumidify incoming outdoor air in summer, reducing the load on your air conditioner. This is more relevant in southwestern Ontario where summer humidity is higher.
• Homes with balanced humidity systems: If your HVAC includes a whole-home humidifier and dehumidifier, an ERV works well as part of a comprehensive moisture management strategy.

Ontario Building Code Requirements

The Ontario Building Code has required mechanical ventilation in all new residential construction since 2012, meeting the requirements of CSA F326 (Residential Mechanical Ventilation Systems).[3] This standard specifies minimum ventilation rates based on the number of bedrooms and floor area.

In practice, this requirement is almost always met with an HRV or ERV in Ontario. The code does not specify which type; either satisfies the requirement as long as it is properly sized and installed.

For existing homes, there is no retrofit requirement. However, if you are improving your home's insulation or air sealing, especially as part of a rebate-eligible upgrade, adding an HRV or ERV is strongly recommended. A home that has been air-sealed without adding ventilation will develop air quality and moisture problems.[2]

Installation: What to Expect

Fully Ducted Installation

A fully ducted HRV or ERV has dedicated supply and exhaust ducts running to multiple rooms. This provides the best air distribution and is standard in new construction. In existing homes, a fully ducted installation is more expensive and disruptive because it requires running new ductwork.

Simplified (Partial) Installation

In existing homes, a simplified installation is often more practical. The HRV or ERV connects to the home's existing furnace ductwork for supply air distribution, while using dedicated exhaust ducts (often running to bathrooms and the kitchen area). This approach costs less and works well in homes with forced-air heating systems.[1]

Integration with Your HVAC System

In homes with a forced-air furnace or heat pump, the HRV or ERV can be connected to the existing duct system. The furnace fan distributes fresh air throughout the home whenever the HRV runs. Most modern HRV/ERV units can be wired to activate the furnace fan automatically during ventilation cycles.[7]

In homes without ductwork (baseboard heating, radiant floors), a standalone ducted HRV/ERV installation is required. This typically adds $1,000-$2,000 to the installation cost for the additional ductwork.

Cost Breakdown

ENERGY STAR certified models are available in both HRV and ERV categories and offer higher heat recovery efficiency.[6] The premium for an ENERGY STAR unit is typically $200-$500 over a standard model, but the improved efficiency reduces heating costs year over year.

Indoor Air Quality Benefits

Beyond energy savings and building code compliance, HRVs and ERVs provide meaningful improvements to indoor air quality:

• Continuous fresh air supply: Unlike opening a window, an HRV or ERV provides controlled, filtered ventilation 24 hours a day without significant heat loss.[2]
• Wildfire smoke filtration: With Ontario experiencing more frequent wildfire smoke events, an HRV or ERV with MERV 13+ filters can filter incoming air while keeping windows closed.
• Radon mitigation: Health Canada identifies indoor radon as the leading cause of lung cancer in non-smokers. An HRV can reduce indoor radon levels by 25-50% in most homes, making it particularly effective in airtight homes with low natural ventilation.[5]
• CO2 and VOC reduction: Occupied homes accumulate carbon dioxide and volatile organic compounds from building materials, cleaning products, and cooking. Mechanical ventilation keeps these at healthy levels.

Rebates and Incentives

HRVs and ERVs may qualify for Ontario rebates, typically when installed as part of a broader energy efficiency upgrade:

• Home Renovation Savings Program (HRS): As of early 2026, the HRS does not list HRV or ERV as a standalone eligible category for residential rebates. However, ventilation equipment may qualify as part of a broader energy efficiency upgrade. Program details evolve, so check homerenovationsavings.ca for current eligibility.[4]
• Enbridge Gas commercial/industrial programs: Enbridge offers incentives of $200-$5,000 per unit for commercial ERV/HRV installations (up to $8,000 for some applications). Residential programs are more limited.
• Municipal programs: Some Ontario municipalities offer additional incentives for energy efficiency upgrades that include ventilation improvements. Check with your local building department or utility provider.

Maintenance: Keeping Your System Running

Both HRVs and ERVs require regular maintenance to perform well:

• Every 3-6 months: Clean or replace air filters. Most units use washable filters that can be rinsed and dried.
• Once or twice per year: Clean the heat exchange core. Remove it, soak in warm water with mild soap, rinse, and let it dry completely before reinstalling.
• Annually: Check and clean the condensate drain to prevent blockages. Inspect exterior intake and exhaust hoods for obstructions (leaves, snow, ice).
• Every 5-7 years: Have a technician inspect the unit, check motor performance, and verify airflow balance.

Ontario's long winter means your HRV or ERV runs continuously for months. A well-maintained system lasts 15-20 years. Neglecting maintenance shortens lifespan and reduces efficiency.

Frequently Asked Questions