HRV and ERV ventilators in Ottawa: service, balancing and new installs

What the ventilator in the basement does

Natural Resources Canada describes an HRV as two separate air streams in one box: stale, damp air from kitchens, bathrooms and laundry goes out, and filtered fresh air comes in through a wall hood. A heat-exchange core between them lets the outgoing air warm the incoming air in winter.

Newer houses are built airtight, so they rely on mechanical ventilation. Ontario’s Building Code in force until the end of 2024 required a mechanical ventilation system in every dwelling unit with electrical power.

HRV or ERV for an Ottawa house

Ottawa’s January nights average -14.3°C, and about 16 nights a year drop below -20°C (Environment Canada normals). NRCan says most units start a defrost cycle below -5°C. NRCan lists a frozen core as a reason to call a contractor, who may need to rebalance by raising exhaust flow or lowering supply flow.

An ERV also moves moisture: in winter it keeps some humidity indoors, in a humid July it keeps some out and eases the air conditioner. NRCan adds that dry winter air can come from over-ventilation or an oversized unit. Ask whether a slower setting would help before you price an ERV or a furnace humidifier.

Balancing: the number that matters

A ventilator should bring in as much air as it sends out. NRCan explains why: more air out than in can pull carbon monoxide back from a furnace, water heater or fireplace and draw soil gases through the basement. More air in than out pushes damp air into walls and the attic, where it condenses.

Ontario’s 2012 code set the line for installs under it: the lower flow at least 90% of the higher one unless the maker says otherwise, with start-up following the maker’s balancing procedure. HRAI, the Heating, Refrigeration and Air Conditioning Institute of Canada, certifies HRV/ERV balancers and keeps a public lookup. Ask who balances the unit.

What the yearly service should cover

NRCan lists what a contractor’s annual visit should include:

• Filters, core and fans cleaned or replaced as the maker specifies.
• Condensate drain and pan cleared, with the trap in the line intact.
• Outside hoods and screens clear of leaves, snow and frost.
• Controls and wiring checked, especially parts inside the air streams, and the defrost system tested.
• Airflows measured, written on the unit’s maintenance label, and rebalanced if needed.

NRCan says the contractor should give you a written report; ask first whether it costs extra. Pair it with the yearly furnace service.

New homes and houses you just bought

NRCan suggests more high-speed running in a new house’s first year, while building materials give off moisture. If the house is under two years old, call the builder first and keep Tarion’s year-two warranty in mind.

For a resale house with an HRV, NRCan recommends a service visit with a balance test.

Signs to describe in your request

• Unit dead or breaker tripped. NRCan says to leave the breaker until a contractor finds the cause.
• Weak airflow at the grilles, a frozen core, or a unit stuck on one speed.
• Water on the floor, or wet or iced duct insulation, which NRCan lists as damage to repair.
• Poor air quality or excess moisture throughout the house, which NRCan says can mean the minimum ventilation rate is too low.

Dusty shared ducts are a separate job: duct cleaning.

What moves the price of a new unit

HomeStars puts an Ottawa install at about $1,800–$4,500. The spread comes from:

• Ducts. A unit tied into the furnace’s return duct uses existing runs. Homes with baseboards or hot water heat need ducts of their own, $1,300–$6,600 on the Canada-wide guide.
• HRV or ERV, and the model. Units run $700–$2,900.
• The furnace blower. On furnace ducts it runs at low speed whenever the ventilator does; NRCan recommends an electronically commutated motor.
• Permit. The City’s permit-exempt list names air conditioners and heat pumps, and ventilators are absent from it. Ask the company or call 3-1-1.

In Ontario, home repair work over $50 needs a written agreement, and an estimate can be exceeded by 10% at most unless you sign a change. Ontario also restricts selling air cleaners and HVAC equipment at your door unless you invited the business.

Who handles your request

Ottawa Heating Desk passes your request to one independent local company that works on home ventilation. That company calls you back, looks at the unit and does the service, balancing or installation.