Installation of a Fantech HERO 150H air exchanger with an EDF8 wall control in Montréal-Est

Ventilating an electrically baseboard-heated house: the entire network still has to be built

A house heated with hot water or electric baseboards has no ductwork. No furnace, no central fan, no return air, nothing to connect to. In the eastern part of the island, where a large portion of the postwar housing stock was built or converted to electric heating, this is the starting point for almost all of our ventilation projects.

The Montréal-Est bungalow discussed here had thermostat-controlled baseboards in every room, a finished basement, and exactly zero inches of ductwork. The owner wanted to address two irritants: moisture condensing on the windows from November to March, and episodes of outdoor odors that would settle into the house on certain evenings and never leave.

Why electric heating worsens the air problem

A forced-air house circulates its air volume several times per hour, even without mechanical ventilation. Odors dissipate, humidity is distributed, and temperature differences are reduced.

A baseboard-heated house does not circulate air. Each room becomes an isolated compartment as soon as the door is closed. The back bedroom accumulates CO₂ all night; the bathroom retains its humidity for hours; the basement holds on to its stale air. Add a renovated envelope—replacement windows, blown-in attic insulation, complete caulking—and no air-exchange mechanism remains.

This is exactly the profile addressed by a whole-home air exchanger with a fully dedicated duct network. It is also the most demanding profile to install, because everything has to be built from scratch.

Choosing the Fantech HERO 150H

Seven main rooms, a finished basement, two bathrooms: our airflow calculation put us at around 90 to 100 CFM in continuous operation, with a higher peak requirement during showers and cooking. We chose the HERO 150H, which provides a comfortable reserve on both sides of that target.

• Airflow range: 36 to 150 CFM at 0.4 in. water column
• Connections: 6 in., round, on top of the unit
• Dimensions: 24 7/8 in. (H) x 27 7/8 in. (W) x 13 3/8 in. (D)
• Weight: 51 lb
• Power supply: 120 V, 1.4 A max
• Power consumption: 59 W at low speed, 180 W at high speed
• Adjusted sensible recovery efficiency: 86 %
• Sensible recovery: 80% at 0 °C, 65% at -25 °C
• Defrosting: by recirculation, with a mechanical backdraft damper
• Filtration: MERV 8 or optional MERV 13

The range from 36 ft³/min at the low end to 150 at the high end matters just as much. A unit that cannot go low enough forces you to ventilate too strongly continuously, which dries out the house in January and drives up baseboard-heater consumption. The wide range makes it possible to run the unit continuously at low speed—the right way to use an HRV—and increase the output only when necessary.

Filtration, the central argument on the eastern side of the island

One objection comes up systematically in this area: why deliberately bring in outdoor air when outdoor air is precisely the problem?

The answer lies in a fact that is often misunderstood: without an air exchanger, outdoor air still enters. It comes in through foundation cracks, around window frames, through the attic hatch, and via the floor drain—without passing through any filter and without allowing you to choose either the airflow rate or the entry point.

An HRV reverses this situation. Air enters through a single, selected point and passes through a filter. We specified the MERV 13 upgrade, capable of capturing fine particles down to the submicron range, rather than the standard filter. The intake hood was positioned at the rear of the building, on the side opposite the truck route, and elevated to avoid the most heavily polluted layer of air near the ground.

The EDF8 wall control, and why it was chosen

The control installed in the hallway is not a simple switch. The EDF8 model is a multifunction digital control that manages four speeds and three modes:

Ventilation mode

Normal operation: both fans run, stale air is exhausted, fresh air enters, and the core recovers the heat. This is the default mode, set here to the second speed continuously.

Recirculation mode

The outdoor damper closes, and the unit circulates indoor air through the filter without bringing in fresh air. This is precisely the mode that addressed the client's second concern. During an outdoor odor episode—an evening with easterly winds, an agricultural burn, or a nearby paving project—the homeowner switches to recirculation from the hallway. The house continues to circulate and filter its air without drawing in whatever is happening outside. Once the episode is over, they switch back to ventilation.

No other strategy provides this level of control. A range hood or bathroom fan only draws in more unfiltered outdoor air.

Standby mode

The unit shuts off, except during defrost cycles. Useful during an extended absence, but best avoided the rest of the year: a stopped HRV no longer protects against winter humidity.

For homeowners who prefer automatic control, the ECO-Touch IAQ control modulates the flow rate according to the measured concentration of volatile organic compounds. We recommend it for homes where no one wants to think about ventilation.

The dedicated duct network: the real workload

The unit accounts for only a fraction of the project. The duct network accounts for the rest.

Exhaust outlets — Main bathroom, basement powder room, and one return in the kitchen area, away from the stove. The HRV does not replace the range hood: it captures residual moisture and odors, not cooking grease.

Supply outlets — Bedrooms and living room, with grilles positioned to sweep across the room rather than blow directly onto a bed. In a baseboard-heated home, this supply network makes all the difference: it is the only air movement the house will have.

Routing — Rigid ductwork in the main sections, aluminized flexible duct for the final connections, with wide bend radii. A sharply bent flexible duct adds as much pressure loss as several dozen feet of straight duct, and these invisible losses then prevent the calculated flow rate from being reached.

Insulation — Both exterior sections, the fresh-air intake and stale-air exhaust, are made with insulated ductwork and a continuous vapor barrier. An uninsulated fresh-air duct running through a heated basement condenses along its entire length, and the water eventually ends up in the finished ceiling. This is the most common correction we make to installations completed elsewhere.

Exterior hoods — Separated by more than 6 feet to prevent air short-circuiting, kept away from the dryer outlet and any combustion-appliance vent, and high enough that February snow does not block the intake. A perfectly balanced unit in October can lose one-third of its flow beneath a snowbank.

Condensate drain — Connected to the floor drain with a trap. Without a trap, the unit draws air through the drain line, balancing becomes unstable, and sewer odors can rise into the home.

Balancing—the step too many installations skip

The label attached to the unit shows the relationship between the flow rate in ft³/min and the measured pressure at the supply-air and stale-air outlets. Balancing is performed at Normal speed with a differential pressure gauge, adjusting the dampers until the two flow rates are equal within a 10% tolerance.

An unbalanced HRV does the opposite of what is expected. Under negative pressure, it draws air in through the foundation, floor drain, and crawl space—and in a home where a combustion appliance remains, it can encourage flue-gas backdrafting. Under positive pressure, it pushes humid air into wall cavities, where it condenses against the exterior cladding.

Mistakes to avoid with an air exchanger

1. Never balancing the system. A connected unit that blows air is not necessarily a functional system.
2. Supplying only the basement. Fresh air must reach the bedrooms, where occupants spend one-third of their lives.
3. Running the unit only intermittently. In continuous operation at low speed, an HRV consumes less energy and works better than in short, high-speed cycles.
4. Using uninsulated flexible ducting on exterior sections.
5. Forgetting the drain trap.
6. Neglecting the filters. Check them every three months, wash the core once a year, and keep the exterior hoods clear of snow and lint. With a MERV 13 filter, maintenance is even more important: a clogged fine filter quickly restricts airflow.

The result

The unit runs continuously at low speed, automatically switching to a higher speed during showers. Condensation on the windows has disappeared, except on the oldest pane. And recirculation mode has become the default response on evenings when there are odors—something the house simply could not do before.

Our residential ventilation practice in Greater Montreal

At AirGreen, we design and install ventilation systems in Montréal, Laval, Longueuil, on the North Shore, and on the South Shore. Homes with electric baseboard heating in Montréal-Est, Pointe-aux-Trembles, and Rivière-des-Prairies account for a significant share of our HRV projects because they require a complete duct network rather than a simple connection to an existing furnace.

Our method does not vary. We calculate the required airflow based on the number of rooms before choosing a unit. We check the service clearances needed to remove the filters and core. We position the exterior hoods according to prevailing winds, contamination sources, and snow accumulation. We balance the system during commissioning and record the readings. And we show the customer how to use the controls, because a unit whose modes no one understands eventually gets used in only one mode.

For an evaluation of an HVAC installation or the addition of an air exchanger in Montréal-Est, the east end of the island, or elsewhere in Greater Montreal, our team visits your home, takes measurements, and proposes a system sized for the actual house.