A house heated with electric baseboard heaters, no existing duct network, and 231 ft³/min to distribute across eight rooms
Most articles about heat recovery ventilator installation describe the easy case: a house with a forced-air furnace, where the HRV is connected to the existing system with two connections. This is not that kind of project.
In Saint-Étienne-de-Beauharnois, the house is heated entirely with electric baseboard heaters. No furnace, no plenum, no air ducts in the house. None. To ventilate this house, it was necessary to design and build a complete dedicated duct network, from the first bathroom grille to the last bedroom register.
This is the type of installation that separates a serious quote from an improvised one, and it is where the price difference that homeowners do not always understand when comparing quotes comes into play.
The starting point: electric heating and no air distribution
The house has eight habitable rooms spread over two levels, with a finished basement. For years, the homeowners had lived with the usual compromises of a tight, unventilated house: heavy condensation on the north-facing windows, stagnant air in the basement, and a bathroom whose wall-mounted fan barely exhausted anything anymore.
The bathroom fan, precisely, deserves clarification. An exhaust fan removes stale air and discharges it outdoors, without recovering the heat or compensating with a controlled supply of fresh air. In a tight house, it creates negative pressure, drawing cold air in through the smallest cracks. An HRV does the opposite: it extracts and supplies equal volumes of air while recovering heat along the way.
Sizing an HRV: a method, not intuition
Room-by-room calculation
Sizing a heat recovery ventilator is not based on floor area. It follows the approach of the CSA F326 standard, adding the airflow rates assigned room by room:
- Primary bedroom: 10 L/s (approximately 21 ft³/min)
- Each other habitable room: 5 L/s (approximately 10.6 ft³/min)
- Kitchen, bathrooms, laundry room, finished basement: additional airflow
For this house, the calculation resulted in a total ventilation capacity significantly higher than what a 150 ft³/min unit could deliver once the system's pressure losses were taken into account. Hence the choice of a high-capacity unit.
Why we did not go even bigger
An oversized unit is not a free safety margin. It costs more to purchase, takes up more space, and, above all, operates continuously at the bottom of its range, where its recovery efficiency is not at its best. The V230H75RT delivers 78% ERS at 66 ft³/min—a cruising airflow perfectly suited to this house in continuous mode, with capacity available up to 231 ft³/min for periods of high occupancy or elevated humidity.
Proper sizing means placing the normal operating airflow within the unit's maximum-efficiency range, with capacity in reserve above it.
The V230H75RT in numbers
- Airflow range: 65 to 231 ft³/min at 0.2 in. w.c. — 225 ft³/min at 0.4 in. w.c.
- ERS: 78% at 0 °C (at 66 ft³/min) and 67% at -25 °C (at 81 ft³/min)
- Motors: two electronically commutated PMSMs (ECMs)
- Defrost: motorized damper with recirculation
- Ports: 6 in. round, on top
- Dimensions: 21 11/16 in. H × 24 13/16 in. W × 21 in. D
- Weight: approximately 47 lb
- Interior filters: washable MERV 8
- Certifications: ENERGY STAR, HVI, UL, and cUL
The 67% ERS at -25 °C is the figure to remember in Beauharnois-Salaberry. It is the actual performance in cold weather, not the showcase value measured at 0 °C.
Designing a dedicated duct network in a ductless house
The exhaust side
Stale air is extracted where it becomes polluted: bathrooms, kitchen, laundry room, and basement. We installed exhaust grilles in each of these rooms, connected by a collector duct network to the unit.
The kitchen grille is installed away from the stove, never above it, and never connected to the range hood. Grease destroys a heat-recovery core.
The supply side
Fresh air is delivered where people breathe for long periods: bedrooms and the living room. Each bedroom receives its own supply outlet with an adjustable damper.
This is where most rushed installations fail. Supplying only the corridor and hoping the air reaches the bedrooms with the doors closed does not work. A closed bedroom without a direct supply receives only a fraction of what it should, and that is precisely where the occupants spend eight hours a night.
The layout
We prioritized galvanized rigid duct for the main trunks, using insulated flex duct only for short branches and terminal connections. Every change in direction uses a long-radius elbow. Every joint is sealed with mastic before being taped.
In a new duct network of this length, the accumulated pressure drop determines the unit's energy consumption for twenty years. A poorly designed network forces the motors to run faster continuously to deliver the same airflow.
Unit installation
Corner wall bracket
The unit is suspended from its steel bracket secured to the studs and positioned in a corner of the mechanical room. Front clearance was confirmed before installation: on the AI Series, the core and interior filters are removed from the front, and an inaccessible unit will never be serviced properly.
The double drain
The two condensate outlets are joined with a T-fitting to a single drain, with a trap and continuous slope. A high-capacity HRV produces a significant amount of condensate in January, when the warm, humid stale air crosses the -20 °C outdoor air in the core.
A poorly trapped drain allows the unit to draw air from the floor drain. A back-pitched drain lets water stagnate at the bottom of the cabinet.
Top outlets
The configuration with top outlets frees all four sides of the unit and allows a direct upward run to the ceiling. We maintain a straight section at the outlet of each collar before any change in direction: a tight elbow at that precise point restricts airflow and drives up consumption.
What auto-balancing does—and does not do
Virtuo Air Technology continuously adjusts both motors to maintain balance between incoming and outgoing air, despite dirty filters, wind, or changes in the system’s pressure. This is a real advance, especially in open areas where gusts alter the pressure at the exterior hoods.
What it does not do: adjust air distribution among your rooms. An appliance can be perfectly balanced at its own registers yet send two-thirds of the fresh air into the living room. Distribution is adjusted at the registers, using instruments, room by room. We record the final values on a label affixed inside the door, along with the date.
Five mistakes to avoid in a home without an existing duct network
- Supply the corridor rather than the bedrooms. With the doors closed, the air cannot reach them.
- Undersize the ducts to save on equipment. The resulting pressure drop is paid for in electricity every day.
- Place an exhaust grille and a supply register in the same room, side by side. Fresh air goes straight back outside without circulating.
- Keep the old bathroom fan running continuously in parallel with the HRV. The two interfere with each other.
- Install the exterior hoods less than 1.8 m (6 ft) apart. Exhaust air is drawn back in through the intake.
Maintenance
- MERV 8 interior filters: washable; inspect every 3 months. In agricultural areas, inspect more frequently in spring and during harvest season.
- Core: remove and wash annually, preferably in the fall.
- Exterior hoods: check twice a year, including the grille.
- Drains and trap: visual inspection during every maintenance visit.
Operation and assistance programs
In an all-electric home, every watt counts. The AI Series’ electronically commutated PMSM motors consume a fraction of what traditional motors consumed at an equivalent airflow rate, and modulation allows them to run at low speed most of the time.
Regarding financial assistance, let us stick to the facts: no current Quebec program directly subsidizes an air exchanger for an existing home. The equipment's ENERGY STAR certification does not qualify you for a rebate. In Novoclimat-certified new construction, however, a heat recovery ventilation system that meets the program's criteria is mandatory. And if you are considering adding a wall-mounted heat pump to a home heated with baseboard heaters, plan the ventilation at the same time: the two systems, their locations, and their electrical supplies are easier to coordinate all at once than across two separate projects.
Beauharnois-Salaberry: the wind, the fields, and what they concretely change
Between the Beauharnois Canal and the agricultural fields, there is nothing to slow the wind. This has three direct consequences for an HVAC installation: outdoor hoods are subjected to variable pressures that throw equipment out of balance without active compensation, agricultural dust loads the indoor filters faster than in an urban environment, and the orientation of wall penetrations must take prevailing winds into account rather than just the convenience of the layout.
These are adjustments we make differently in Saint-Étienne-de-Beauharnois, Sainte-Martine, or Salaberry-de-Valleyfield than in a triplex in Le Plateau-Mont-Royal.
Our approach, from assessment to commissioning
Complete assessment, room-by-room airflow calculations, system design, equipment selection, installation, documented adjustment, and handover of the file to the owner. We follow the same approach in Montreal, Laval, Longueuil, the North Shore, the South Shore, and throughout Montérégie.
If your home is heated with baseboard heaters and you are wondering how to install an air exchanger without demolishing the ceilings, we will come to your home, take measurements, and present you with a layout before discussing the price.
AirGreen — Heating, ventilation and air conditioning. RBQ 5645-9605-01. (514) 316-2973 | sales@airgreen.ca