Quick answer: HRV or ERV?
Both
Exhaust stale indoor air, bring in fresh outdoor air, and use a core to pre-warm incoming air in winter.
HRV
Transfers heat only. Best for Ottawa homes with window condensation, larger families, lots of cooking and showers, or a newly built house drying out.
ERV
Transfers heat and some moisture. Best for homes that get very dry in winter, smaller households in tight homes, and homes with central air during humid summers.
Neither
Is a dehumidifier or a humidifier. They manage how much moisture ventilation adds or removes.
Installed cost
Typically $2,500 to $5,500 in Ottawa for either type, depending on ducting and controls.
Maintenance
Clean filters every 2 to 3 months, clean the core once or twice a year, and keep outdoor hoods clear of snow.
Prices are typical Ottawa installed ranges in CAD before rebates, not quotes. The final price depends on the home, the equipment and the ductwork. Oria gives free estimates on new installations.
Why tight Ottawa homes need mechanical ventilation
Modern homes are built to be airtight so they hold heat through −25 °C winters. The downside is that moisture, cooking smells, carbon dioxide and household chemicals have nowhere to go.
That is why most newer Ottawa homes already have an HRV or ERV, and why many older homes add one after new windows, spray foam or air sealing. Without one, you often see condensation on windows, musty basements and stale air by February.
Opening a window in January would ventilate the house but throw away heat. A ventilator does the same job while recovering much of that heat.
How an HRV works
An HRV has two fans and a heat exchange core. One airstream carries stale, warm air out of your kitchen, bathrooms or return ducts. The other draws fresh outdoor air in. The two streams pass each other inside the core without mixing.
In winter, heat from the outgoing air warms the incoming air. Good HRVs recover a large share of that heat, so −20 °C outdoor air enters your ducts much warmer than it started.
The moisture in the outgoing air leaves the house. As it cools in the core, some condenses, which is why an HRV has a condensate drain. The net effect in winter is drier indoor air, which is exactly what a home with foggy windows needs.
How an ERV works
An ERV looks and installs almost the same way, but its core is made from a material that lets some water vapour pass from one airstream to the other along with heat.
In winter, an ERV keeps part of your indoor humidity instead of exhausting it, so the house stays less dry. In summer, it works in reverse, keeping some of Ottawa’s humid outdoor air from reaching your air conditioner.
Most ERVs do not need a condensate drain, because less water condenses in the core. That can make installation simpler where a drain is hard to reach.
HRV vs ERV comparison table
| Factor | HRV | ERV |
|---|---|---|
| What it recovers | Heat only | Heat and some moisture |
| Winter effect on humidity | Lowers indoor humidity | Holds more indoor humidity |
| Summer effect on humidity | Brings outdoor humidity in | Reduces humidity brought in |
| Best for | Condensation problems, big households, new builds | Dry homes, small households, homes with central AC |
| Condensate drain | Usually required | Usually not required |
| Core cleaning | Most cores can be washed in water | Most cores must not be washed; vacuum only (check the manual) |
| Typical installed cost in Ottawa | $2,500 to $5,500 | $2,500 to $5,500 |
Which is better for Ottawa homes?
Neither is better everywhere. The right choice depends on your home’s moisture balance in January, when the difference shows most.
Choose an HRV if:
- Your windows fog or frost up on cold mornings.
- Four or more people live in the home, or you cook, shower and dry laundry indoors a lot.
- The house is new and still drying out from construction moisture.
- You have a damp basement and want ventilation to carry moisture out.
Choose an ERV if:
- Your home drops below about 25% humidity in winter, with static shocks, dry skin or cracked wood floors.
- You live in a tight, smaller home with one or two people.
- You run a furnace humidifier all winter and still struggle to keep humidity up.
- You have central air and want less humid outdoor air entering during July heat waves.
Most Ottawa homes are comfortable at about 30% to 40% indoor humidity in winter, lower during the deepest cold snaps to avoid condensation. Our guide to humidifiers in Ottawa winters explains how ventilation and humidification work together.
What about the cold?
At −25 °C, both types need a defrost strategy to keep the core from icing up. When comparing models, ask for the published sensible recovery efficiency at −25 °C, not just at 0 °C. A unit that performs well at −25 °C is built for Ottawa.
Running your HRV or ERV properly
Run it continuously on low.
Ventilators are designed to run all the time. Turning one off lets moisture and pollutants build up.
Use boost when needed.
Bathroom timers or a boost button raise airflow during showers, cooking or parties.
Adjust for the season.
If windows fog in winter, increase ventilation. If the house feels too dry, lower it a little, especially with an HRV.
Smoky days.
On days with heavy outdoor smoke, such as during wildfire season, reducing ventilation for a few hours can keep smoke out.
Get it balanced.
Intake and exhaust airflow should be balanced by a technician, so the house is not pressurized or depressurized.
HRV and ERV maintenance schedule
| Task | How often | Notes |
|---|---|---|
| Clean or replace filters | Every 2 to 3 months | Vacuum or rinse washable filters; let them dry fully |
| Clean the core | Once or twice a year | HRV cores usually wash in lukewarm water; most ERV cores are vacuum-only |
| Check outdoor intake and exhaust hoods | Monthly in winter, and each spring and fall | Clear snow, frost, leaves, bugs and cottonwood fluff |
| Check condensate drain (HRV) | Yearly | Pour water into the drain pan to confirm it flows |
| Professional service and balancing | Yearly or every two years | Fans, controls, defrost and airflow checked |
If you also have a furnace humidifier, replace its water panel (pad) at the start of each heating season. A fresh pad keeps humidity output steady and stops mineral buildup. Many homeowners pair these tasks with a furnace maintenance checklist each fall.
Installation, repair and next steps
Oria Heating and Cooling installs, repairs and services HRVs and ERVs across Ottawa, with 24/7 emergency service available for HRVs. We have served Ottawa homes since 2005 and hold a 5.0-star Google rating from 396 reviews.
Whether you are adding ventilation to an older home or replacing a noisy unit, see our HRV and ERV installation page, ask about adding a furnace humidifier, or call (613) 866-1869 for a free estimate. Rebates may be available; Oria will check current programs for your home.
Frequently Asked Questions
What is the difference between an HRV and an ERV?
Both ventilate your home by exhausting stale indoor air and bringing in fresh outdoor air through a core that recovers heat. An HRV recovers heat only, so it removes moisture in winter. An ERV recovers heat and some moisture, so it keeps more humidity indoors in winter and lets less humid outdoor air in during summer.
Is an HRV or ERV better in Ottawa?
Both work in Ottawa. An HRV is usually better for homes with window condensation, larger families or new construction moisture. An ERV is usually better for tight homes that get too dry in winter, smaller households, and homes with central air during humid summers. Check your winter humidity and window condensation before choosing.
How much does an HRV or ERV cost to install in Ottawa?
A new HRV or ERV typically costs $2,500 to $5,500 installed in Ottawa. The price depends on the unit’s capacity and efficiency, whether it connects to existing furnace ductwork or needs its own dedicated ducts, the controls you choose and how hard it is to run intake and exhaust lines through the house.
Should my HRV run all the time?
Yes. HRVs and ERVs are designed to run continuously at low speed, with a boost setting during showers, cooking or when many people are home. Turning a ventilator off in a tight Ottawa home lets moisture, odours and carbon dioxide build up, which often leads to window condensation and stale air during winter.
Can I wash my HRV or ERV core?
Most HRV cores can be removed and washed in lukewarm water once or twice a year, then dried before reinstalling. Most ERV cores cannot be washed in water because the moisture-transfer material can be damaged, so they are vacuumed gently instead. Always check your unit’s manual before cleaning the core.
Will an ERV replace my dehumidifier or humidifier?
No. An ERV reduces how much moisture ventilation removes in winter or brings in during summer, but it does not add or remove moisture on its own. A damp basement may still need a dehumidifier, and a very dry home may still need a furnace humidifier. An ERV simply makes both easier to manage.
Why are my windows wet even though I have an HRV?
Window condensation with an HRV usually means it is running too low, the filters or core are clogged, the outdoor intake is blocked by snow, or indoor humidity is set too high for the outdoor temperature. Clean the filters and core, check the hoods, raise ventilation, and lower your humidifier setting during cold snaps.
Related Reading
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