Installation of a Broan-NuTone V150H75NS AI Series air exchanger with Virtuo technology in Pointe-Fortune

At the edge of the Montérégie, an unfinished basement and a unit we were finally able to install properly

Pointe-Fortune is the last municipality in Quebec before Ontario. Six hundred residents, nine and a half square kilometres, and 285 dwellings, almost all of them year-round occupied single-family homes. The village sits on the right bank of the Ottawa River, at the level of Lake of Two Mountains, a stone's throw from the Carillon Dam and the ferry linking the north shore.

This is an area we visit regularly, and where we encounter a building configuration that urban Greater Montreal rarely offers us: a detached single-family home supplied by a well, with an unfinished utility basement where the building systems are entirely visible.

For the installation of an air exchanger, this configuration is an advantage. It is still necessary to make the most of it.

Geography that directly affects indoor air

Three characteristics of Pointe-Fortune influenced our technical recommendations:

• Immediate proximity to the water. The terrain is flat, typical of the St. Lawrence Lowlands, with an elevation ranging from approximately 24 m at the lake shore to 48 m toward the southeast. The lower and closer to the shoreline, the more sustained the summer moisture load.
• Inland wetlands. Depressed areas retain water. Basements there are colder, more humid, and more prone to condensation on uninsulated surfaces.
• A geological basement of Cambrian-age sandstone, limestone, and dolomite in the eastern part of the territory. We will return to this later, because this fact has a direct consequence for how a home should be ventilated.

Add to this a population whose average age exceeds forty-four, meaning occupants are often at home twelve months a year, and air exchange is no longer an accessory.

Why a side-port model

The unit was suspended between two joists, beneath an OSB subfloor, in an unfinished basement shared with the home's water heater and water-treatment system.

The height constraint

A HRV with top-mounted ports requires vertical clearance above the cabinet to accommodate the four collars and start the elbows. In a utility basement where headroom is already limited by joists and existing pipes, that clearance simply does not exist.

Models with side ports — identifiable by the S suffix in the AI series nomenclature — move all four connections to the sides of the cabinet. The enclosure can then fit high, almost against the subfloor, with the ducts running horizontally along the joist bays. This is exactly the geometry we wanted here.

The trade-off exists, and we say so: a side connection sometimes requires an additional elbow compared with a top connection. We compensate by carefully managing bend radii and avoiding any sagging flex duct.

What the V150H75NS delivers

Two figures deserve attention. The 82% sensible recovery efficiency places this unit at the top end of the residential market: at −18°C outdoors and 21°C indoors, the core returns the vast majority of the outgoing air’s heat to the incoming air. And the standard washable MERV 8 filtration is a significant improvement over the still-common MERV 6 — a detail that matters in an area surrounded by fields and wetlands, where pollen and spores circulate freely in spring and fall.

The suspension: hooks, chains, and level

The unit was suspended with chains attached directly to the joists, using hooks screwed into solid wood rather than into the subfloor panel. The distinction is not cosmetic: a 5/8-inch OSB panel cannot reliably support a suspended thirty-five-pound load subject to continuous vibration.

The cabinet was then leveled in both directions before any connections were made. In an HRV, condensation must flow into the drain pan, not toward the nearest joint. A half-degree tilt is enough to send the water the wrong way.

One advantage of an unfinished basement: we were able to maintain clear access on all four sides of the unit. No panel to remove, no enclosure to open. The core and filters can be removed while standing, without a ladder.

The four ports, and the mistake that invalidates the entire installation

The label affixed to the front identifies the unit’s four connections. It is the most mundane part of the product, and the one responsible for the most defective installations in Quebec.

The four ports are:

1. Exhausting stale air outdoors — the outgoing air, after passing through the core.
2. The fresh-air supply to the home — fresh, preheated air distributed to the bedrooms and living areas.
3. The home's stale-air return — drawn from the bathrooms, kitchen, and basement.
4. The outdoor fresh-air intake — raw fresh air, before treatment.

Reversing two of these vents produces a unit that runs, makes noise, consumes energy, and does not ventilate anything. In the worst-case scenario, fresh air enters and immediately exits through the exterior wall without ever reaching the house, while stale air circulates in a loop indoors. We have been called to correct this type of connection at customers' homes on both the North Shore and the South Shore, on units installed a few years earlier by another contractor—and whose owners had been complaining ever since without understanding why.

The check takes two minutes: place your hand in front of each outdoor grille with the motor running, and verify the direction of airflow.

Insulated or uninsulated: the simple rule

Not all ducts are equal, and they do not all require the same treatment.

• Runs carrying cold outdoor air or humid stale air to the wall must be insulated with a continuous vapor barrier. Otherwise, they become cold surfaces on which the basement's ambient humidity condenses, drop by drop, all winter long.
• The internal distribution runs, entirely within the heated area, can use uninsulated ductwork.

On this job, the outdoor runs were made with black-and-silver-jacketed insulated flex duct, and the connections were sealed with aluminum tape.

Coexisting with the water heater and water treatment system

The basement also houses a water heater and a water treatment system—a common setup in Pointe-Fortune, where the water supply generally comes from a well. This arrangement requires three precautions that we apply systematically.

First, clearances. The unit must not block access to the water heater's anode, pressure relief valve, or drain valve. An emergency plumber should never have to disconnect an air exchanger to do their work.

Secondly, the condensate drain. It was connected with a continuous slope to a suitable drain. We never connect an HRV drain to a water softener's brine discharge line: the flow rates, pressures, and chemistry are completely different, and backflow is predictable. When the available drain is too far away or too high, the solution is a small dedicated condensate pump, not a back-sloping hose that we hope will work.

Third, the electrical supply. The unit has its own circuit and its own accessible disconnect, away from the water lines.

Commissioning

Once the entire duct network is complete, with doors and windows closed and exhaust hoods turned off, we program the continuous ventilation airflow and the boost airflow, then select the installation configuration corresponding to the chosen connection type — here, a fully independent system with its own duct network.

The Virtuo technology then takes over: the unit measures its own airflow and continually recalibrates, maintaining the balance between supply and exhaust throughout its service life. This is the manufacturer’s answer to the industry’s longstanding problem: units balanced only once, on the day of installation, then gradually thrown out of balance by clogged filters and aging motors.

ENERGY STAR, fan efficiency, and radon: three concepts to understand before buying

“ENERGY STAR certified in Canada only”: what the label really says

The label affixed to the unit contains a statement that few homeowners read and almost no salesperson explains: the product meets the ENERGY STAR requirements established by Natural Resources Canada and the U.S. EPA, and it meets these requirements only when used in Canada.

This is not a legal technicality. The ENERGY STAR thresholds applicable to HRVs differ between the two countries, and the Canadian program is structured around our climate realities. The same unit may therefore be certified in Canada but not in the United States. The practical consequence: a U.S. product sheet stating “ENERGY STAR: no” tells you nothing about the unit’s Canadian status. We have seen customers rule out an excellent model because they misread a product sheet.

For AI-series HRVs, Canadian certification is based on two measured criteria: sensible recovery efficiency above 80% and ventilation efficiency expressed in CFM per watt. The highest-performing certified models in the range deliver around 2.2 to 2.3 CFM per watt.

CFM per watt, or how to estimate the true cost of continuous ventilation

This is a calculation we routinely make when preparing a quote, yet it is missing from almost every purchasing discussion.

An air exchanger operates continuously, 8,760 hours per year. Its consumption depends not on its rated power, but on its ventilation efficiency: the number of cubic feet per minute it moves for each watt consumed.

Let us take a unit set to 60 cu. ft./min. in continuous ventilation mode, with an efficiency of 2.2 cu. ft./min. per watt:

60 ÷ 2.2 = approximately 27 watts in continuous operation, or nearly 240 kWh per year.

The same airflow delivered by a unit rated at 1.1 cu. ft./min. per watt would require approximately 55 watts, or nearly 480 kWh. The difference therefore approaches 240 kWh each year, over a useful service life of fifteen to twenty years. It is this trade-off — not the purchase price alone — that should guide the choice between two models with comparable airflow.

The PMSM/ECM motors in the AI series are precisely what makes these figures achievable. They offer a second, less visible advantage: they maintain their airflow as filters become loaded, whereas a conventional motor's airflow drops sharply without anyone noticing.

Radon: what an air exchanger does, and what it does not do

The bedrock in the Pointe-Fortune area is composed of sandstone, limestone, and dolomite. With this type of formation, the issue of radon deserves attention — as it does in several rural areas of Vaudreuil-Soulanges and western Montérégie.

Let us be precise, because this subject lends itself to commercial shortcuts.

An air exchanger is not a radon mitigation system. When measured concentrations exceed the Canadian guideline of 200 Bq/m³, the recognized method is active sub-slab depressurization, installed by a certified professional. No HRV, regardless of its price, can replace this intervention.

That said, a properly installed HRV makes two real contributions:

• It dilutes them. By continuously replacing the air, it lowers the concentration of soil gases present indoors. When measurements are only slightly above the threshold, the effect is measurable.
• It prevents the house from becoming depressurized. This is the point we consider most important, and least understood. A depressurized house — because the range hood, dryer, and bathroom fans exhaust more air than enters — actively draws soil gases through slab cracks and the French drain. Balanced ventilation eliminates this infiltration force. This is where the continuous self-balancing of Virtuo technology truly proves its value.

Our position: have the radon level measured—the long-term test kits cost a few dozen dollars—and then decide. An air exchanger is a good thing in every case, but it should never be used as an excuse not to measure.

Maintenance in a mechanical basement

The clear access provided by this installation is only valuable if it is preserved. The instruction we leave homeowners is brief:

• Do not stack anything underneath or in front of the unit. An unfinished basement always ends up being used to store boxes.
• MERV 8 filters: wash or vacuum them quarterly during pollen and harvest seasons, and twice a year for the rest of the year.
• Heat-recovery core: rinse with lukewarm water at the beginning and end of the heating season.
• Exterior grilles: clear snow away in winter and remove leaves and cobwebs in the fall.
• Drain: visually check the flow once a year; detach and rinse the hose if necessary.

Four mistakes specific to unfinished-basement installations

1. Anchoring the chains in the subfloor instead of in the joists.
2. Choosing a top-vent model in a space where the available headroom does not allow it, then crushing the elbows to make it fit.
3. Connecting the condensate drain to the discharge line of the water-treatment system.
4. Failing to check the direction of airflow at all four vents before leaving the job site.

AirGreen in Pointe-Fortune and Western Montérégie

Pointe-Fortune is located about sixty kilometres west of Montréal, via Highway 40. It is far from the usual routes of most HVAC installation contractors in Greater Montréal, and that is precisely why we go there: homeowners in this area deserve the same level of workmanship as those in Laval, Longueuil, the North Shore, or the South Shore.

We serve Pointe-Fortune, Rigaud, Vaudreuil-Dorion, Les Coteaux, Saint-Zotique, and the entire Vaudreuil-Soulanges RCM for air exchangers, heat pumps, air conditioning, and HVAC maintenance.

On this project, as on the others, the sequence remained the same: measure the actual space, assess the building’s geology and environment, choose the vent configuration accordingly, and only then select the model. The opposite approach—choosing the equipment first and adapting it to the building afterward—is the source of most of the installations we are called upon to correct.