HRV vs ERV in Ontario: Choosing and Using Home Ventilation

The difference between HRV vs ERV systems comes down to moisture. A heat recovery ventilator (HRV) exchanges stale indoor air for fresh outdoor air and recovers much of the heat, while an energy recovery ventilator (ERV) does the same but also transfers some humidity between the two airstreams. In Ontario, an HRV usually suits homes that run humid in winter, and an ERV suits tight homes that become too dry in winter or too sticky in summer.

Both are designed to give you fresh air without throwing away the heat you paid for. This guide explains how they work, how to choose, and how to set and maintain the one you have.

Why do Ontario homes need mechanical ventilation?

Older homes "breathe" through leaks, often far too much: 7–15 air changes per hour at 50 pascals (ACH50) is common. New homes and well-sealed older homes are much tighter, typically around 2.5–3.5 ACH50. That saves energy but traps moisture, cooking smells, carbon dioxide and pollutants from furniture and cleaning products.

The Ontario Building Code requires mechanical ventilation in new houses, and an HRV or ERV is the usual solution. If you are air sealing an older home, ask your energy advisor whether you need added ventilation. See our air sealing guide.

How do HRVs and ERVs work?

Inside the unit, a core lets the outgoing and incoming air streams pass close to each other without mixing. Heat moves from the warmer stream to the cooler one. In winter, outgoing warm air preheats incoming cold air.

• HRV core: transfers heat only. Moisture leaves with the exhaust air, which helps dry out a humid house.
• ERV core: transfers heat and some moisture. In winter, part of the indoor humidity stays inside; in summer, part of the incoming humidity is rejected.

Typical units recover roughly 60–80% or more of the heat in the exhaust air (sensible recovery efficiency at test conditions). Efficient models use ECM fan motors that draw relatively little power, often in the tens of watts on low speed.

HRV vs ERV: which is right for your home?

Situation	Usually better choice	Why
Winter window condensation, high indoor humidity	HRV	Exhausts more moisture
Large household, lots of showers and cooking in a smaller home	HRV	Higher moisture load
Very airtight home with dry winter air (below ~30% RH)	ERV	Retains some indoor moisture
Humid summers, central air conditioning, want less dehumidification load	ERV	Rejects some incoming humidity
Northern Ontario, very cold winters	Either, with appropriate defrost	Cold climates need defrost capability
Unsure	Ask for a ventilation assessment	Depends on house, household and humidity history

Neither is a dehumidifier or humidifier. An ERV moderates humidity swings; it will not fix a wet basement, and an HRV will not dry a house with a major moisture source such as an unvented dryer.

What does an HRV or ERV cost?

These are rough 2026 estimates for Ontario, not quotes:

• Unit: roughly $1,000–$2,500 depending on capacity and features.
• Installed in a new home or during major renovations: often included in the builder's price.
• Retrofit in an existing home with ducted heating: roughly $2,500–$5,000, more if dedicated ductwork is needed.
• Room-by-room ductless ventilators: small through-wall units are available for homes without ducts; costs and performance vary.

Running cost is usually modest. A unit drawing around 50 W continuously uses about 440 kWh a year, roughly $60 at an example all-in price of 14¢/kWh. If the HRV is tied into a furnace blower that runs continuously, the furnace fan may use more than the HRV itself.

How should you set an HRV or ERV in winter?

Your controls may include a dehumidistat, a low/high speed switch, timer buttons in bathrooms, and an intermittent or recirculation mode. Good general practice:

1. Run it continuously on low as the baseline. Most homes need steady ventilation, not occasional bursts.
2. Boost to high during showers, cooking or gatherings, using bathroom timers where fitted.
3. Set the dehumidistat (if your unit has one) to around 40–50% in winter. If windows fog or frost, lower it so the unit runs more; if the air feels very dry, raise it or reduce run time.
4. Avoid shutting it off for long periods to save energy. The heat recovery means you lose much less heat than through open windows or bathroom fans alone.
5. Make sure it is balanced. Incoming and outgoing airflows should be roughly equal. A contractor can measure and adjust this; an unbalanced system can pressurize or depressurize the house.

For target humidity levels by outdoor temperature, see our winter humidity guide.

HRV and ERV maintenance checklist

Most problems come from neglect, not equipment failure.

1. Clean or replace the filters every 2–3 months. Many units have washable mesh filters; vacuum or rinse and dry them.
2. Clean the core once or twice a year. HRV cores can often be rinsed in lukewarm water; many ERV cores cannot be washed, so check the manual.
3. Check the outdoor hoods for leaves, lint, wasp nests and, in winter, frost or snow. Blocked intakes are common.
4. Clear the condensate drain on HRVs, and make sure the drain line has a trap and is not frozen or blocked.
5. Check that defrost works in cold weather. Ice in the core reduces airflow.
6. Have airflow checked when you change other HVAC equipment.

If your home's ventilation is linked to the furnace ductwork, clean filters on both systems matter. See our furnace filter guide.

Caution: Do not cover or block HRV or ERV outdoor hoods to stop cold drafts. Keep intake hoods well away from dryer vents, gas appliance exhausts, car exhaust in garages and garbage bins.

Frequently asked questions

Is an HRV the same as an air exchanger?

"Air exchanger" is a common term in Canada for an HRV or ERV. Some basic exchangers have no heat recovery, so check the label.

Should I turn my HRV off in summer?

Many homeowners run it less in hot, humid weather, especially with an HRV. An ERV handles summer humidity better. Ventilation is still needed in summer if the windows stay closed.

Can I add an HRV to an older home?

Yes, especially if it has ducted heating. It is most worthwhile after air sealing, when natural leakage no longer provides enough fresh air.

Why does my HRV make the house feel cold?

Incoming air is tempered, but it is still cooler than room air. Check that the core is clean, defrost is working, and supply registers are not aimed at seating areas. An imbalance between airflows can also cause drafts.