When a West Island home finally breathes the right way
A home in Dollard-des-Ormeaux built in the early 1980s, renovated twice, insulated with spray foam in the basement, and fitted with new windows in 2019. On paper: an energy-efficiency success. In reality: fogged-up windows from November to March, a musty smell after returning from vacation, and an upstairs bathroom that took forty minutes to dry after a shower.
The homeowner called us believing there was a humidity problem. The actual problem was ventilation. The two can look similar, but they require completely different solutions.
The real diagnosis: an airtight building envelope without a fresh-air strategy
At AirGreen, we always start by measuring before making a recommendation. On site, we found three things:
- A relative humidity level of 58% in the middle of January, whereas a reasonable target for a Quebec home in winter is between 30 and 40%.
- Two bathroom fans exhausted air… without anything replacing it, other than unwanted air infiltration through electrical outlets and around the rim joists.
- There was no mechanical supply of fresh air. The house “breathed” only through its air leaks, and those had been sealed during the renovations.
This is the classic scenario in West Island homes renovated in stages: the building envelope is improved without ever adding the system needed to compensate for the loss of natural ventilation. The result: indoor pollutants—CO₂, volatile organic compounds from building materials, and moisture from cooking and showers—remain indoors.
An air exchanger does more than simply “ventilate.” It creates a balanced airflow: as much stale air is exhausted as fresh air is brought in, without depressurizing the home, while recovering heat from the expelled air along the way.
Why we chose the Fantech HERO 150H
Choosing an HRV (heat recovery ventilator) is not a matter of picking something at random from a catalog. For this approximately 1,850 sq. ft. home with two floors plus a finished basement, the Fantech HERO 150H checked all the right boxes.
The figures that really matter
- Airflow range: 36 to 150 cu. ft./min at 0.4 in. w.g. — more than enough to meet the home's continuous ventilation requirement while maintaining headroom at high speed.
- Sensible recovery efficiency: 80% at 0 °C and, more importantly here, 65% at -25 °C. Many specification sheets show only the value at 0 °C. In Quebec, performance in extreme cold is the only figure that truly reflects what you will experience in January.
- Adjusted sensible efficiency : 86 %.
- Power consumption: 59 W at low speed, 180 W at high speed. In continuous low-speed operation — the normal mode — the electrical load is comparable to that of a light bulb.
- Connections: 6-inch round ducts, top ports (top-port), 120 V / 1 phase.
- Certifications: HVI and ENERGY STAR.
- Weight: 51 lb (23 kg), 24 7/8 in. high × 27 7/8 in. wide × 13 3/8 in. deep.
Recirculation defrosting: the detail that makes a difference in winter
This was the technical argument that made the difference. Fantech offers two frost-control mechanisms in its residential lineup: supply fan shutdown and recirculation defrosting.
The first simply cuts off the fresh-air supply while the core defrosts. It works, it is robust, and it is economical — but during these cycles, your house is under slight negative pressure and receives no fresh air.
The HERO 150H uses recirculation defrosting: the unit circulates indoor air through the core to warm it, without ever putting the house under negative pressure. Three concrete advantages at -22 °C in Dollard-des-Ormeaux:
- No unintended air intake through cracks, so no cold drafts felt near the baseboards.
- Better overall energy efficiency throughout the heating season.
- Less risk of stale air and indoor condensation during the cycles.
These recirculation models also have a mechanical backdraft damper interlocked with the unit, which blocks outdoor air when the HRV is off — a point not to overlook if you may one day integrate it with the central air-handling unit.
The job, hour by hour
The installation took one and a half days, with two technicians.
Choose the location before drilling anything
We suspended the unit from the basement ceiling, in the mechanical room, near the existing furnace. Three criteria guided the location:
- Drain access: the HERO produces condensate. An accessible drain with a properly primed trap is required. We regularly see installations where the condensate has been connected wherever convenient—sometimes to a drain pan dedicated to another appliance, which eventually causes water damage.
- Service clearance: the owner must be able to open the cabinet door and remove the filters without dismantling a duct. We systematically allow the necessary frontal clearance.
- Acoustic decoupling: spring hangers and flexible connectors at all four connections. A properly installed HRV is barely audible in the room above.
Outdoor air intakes: where many installations go wrong
Two penetrations on the rear façade, with weatherproof caps featuring rodent screens, spaced more than 6 feet apart. This distance is not decorative: if they are too close together, the fresh-air intake will draw back in the stale air just exhausted, and the system will operate in a closed loop without anyone noticing.
We also checked the clearances from the dryer vent, the furnace terminal, and the area where snow accumulates in winter. For this house, with its rear façade facing the yard, we had to ensure that the air intake would not be buried after a heavy snowfall.
A partially dedicated system
The selected configuration is the partially dedicated system: dedicated exhaust ducts from the two bathrooms and the kitchen, with fresh air injected into the furnace return, approximately 6 feet upstream of the unit.
This choice avoided having to redo an entire distribution network in a finished home, while ensuring that the fresh air would be tempered and distributed by the central blower. A fully dedicated system would have performed better on paper, but would have required opening several ceilings—a cost-benefit trade-off that we clearly presented to the client, with the figures to support it, before they made their decision.
Balancing: the step no one sees but everyone lives with
We balanced the airflow rates using a differential manometer at the unit's measurement ports until the difference between supply and exhaust was less than 10%.
An unbalanced air exchanger is an expensive unit that serves no purpose: if it supplies more air than it exhausts, it pressurizes the home and pushes moisture into the walls; if it exhausts more than it supplies, it draws cold air in through leaks — exactly the problem we were trying to solve. This is the step installers in a hurry skip most often.
The wall control: an RTS timer in the right place
We installed a wired Fantech RTS push-button wall timer in the hallway entrance, just below the existing controls. One press switches the unit to high speed for 20, 40, or 60 minutes, depending on the number of presses — the green LEDs confirm the selection at a glance.
The principle is simple, and that is what makes it effective: the home ventilates continuously at low speed, and the occupant temporarily switches to high speed — after a shower, while cooking, or when several people are entertaining in the basement. No menu, no app, no learning curve.
For clients who want to go further, Fantech also offers the EDF3 multifunction controller (Econo mode, 20 min/hour, continuous), the four-speed digital EDF8, and the VOC-sensing ECO-Feel and ECO-Touch IAQ controls. We systematically present the options, but we do not sell complexity to someone who does not want it.
The errors we correct most often in other installations
On service calls related to air exchangers installed by others in Montreal, Laval, Longueuil, the North Shore, and the South Shore, the same defects keep coming up:
- Outdoor intakes and exhausts too close together — air short-circuiting, with virtually no real-world performance.
- No documented balancing — no report, no measurements, no proof.
- Poorly drained condensate or a dry trap — sewer odors or a leak through the finished ceiling.
- Uninsulated flexible ducts in an unheated attic—condensation inside the duct, followed by stains on the ceiling.
- Unit turned off by the homeowner because no one explained how it works or how much it costs to run. This is by far the most common.
Maintenance: three tasks, twice a year
- Filters: vacuum or rinse them every 3 to 6 months. A MERV 8 or MERV 13 filtration option is available for households with allergies.
- Heat exchanger core: remove it and wash it with warm, soapy water once a year.
- Outdoor grilles: clear them of lint, leaves, and snow—a blocked grille throws off the entire balance.
We provide this routine in writing to every customer, along with the airflow rates measured on the day of the HVAC installation. This document serves as the reference during the next HVAC maintenance visit.
Codes, Novoclimat, and financial assistance: what you need to know
In new construction, balanced mechanical ventilation is governed by the Quebec Construction Code, and the Novoclimat program imposes performance requirements that make an HRV essential. In renovations, the requirement is less direct, but the principle remains the same: the more airtight a house is, the less it can tolerate the absence of an air exchanger.
When it comes to financial assistance, the situation is evolving, and programs mainly target insulation, air sealing, and heating systems. Before promising anything to a customer, we verify eligibility for the specific project based on the programs in effect when the work is carried out. We prefer a verified answer to a convenient promise.
Where we provide service
AirGreen installs and maintains air exchangers, heat pumps, wall-mounted air conditioners, and central systems in Dollard-des-Ormeaux, Pointe-Claire, Kirkland, Beaconsfield, Pierrefonds, Saint-Laurent, and throughout the island of Montreal, as well as in Laval, Longueuil, the North Shore, and the South Shore.
If your windows drip in winter, if the air smells stale after two days away, or if you renovated without ever adding ventilation, contact us. We measure first. Then we make recommendations.