Installation of a Venmar AVS N Series A130H65RT air exchanger with Virtuo Air Technology in Mercier, on the South Shore

The self-adjusting air exchanger: what it changes in practical terms on a job site

For thirty years, commissioning an air exchanger followed the same process. The installer connects a pressure gauge to the cabinet's pressure taps, reads two values, opens or closes mechanical dampers on the collars, reads them again, readjusts, and repeats. The process takes between thirty and forty-five minutes when done properly.

And that is precisely where the problem lies: it is not always done properly. We regularly take over installations on the South Shore where the dampers have remained in their factory-default positions, no report was provided, and the unit has been pushing 30% more air than it extracts for six years.

The unit installed at this Mercier job site belongs to a generation that addresses this problem: the Venmar AVS Série N A130H65RT, equipped with the Virtuo Air Technology platform.

What the onboard electronics actually do

On the left side of the cabinet is a control module with an LCD screen and two buttons. This is not a decorative display: it is the interface for an electronic airflow measurement device built into the unit.

The airflow test at startup

As soon as it is connected, the unit automatically starts an airflow test. It measures the actual resistance of the system to which it has just been connected—each elbow, each metre of flexible duct, each grille—and establishes the maximum airflow it can achieve in this precise configuration.

This is a complete reversal of traditional logic. Instead of calculating static pressure in advance and hoping the system behaves as expected, the unit assesses the system as it is and adjusts its motors accordingly.

The printed instruction on the cabinet is also unambiguous: any modification made to the ducts afterward requires the test to be run again. Adding a grille, lengthening a branch, replacing an exterior cap—each of these actions changes the system's resistance, and the unit must learn it again.

The six setup steps

The sequence printed on the front panel consists of six steps, which we follow in order:

1. Connect the unit, then wait for the automatic airflow test to finish.
2. Configure the maximum airflow, adjust it with the (+/-) button, and confirm with OK.
3. Configure the minimum airflow using the same method.
4. Choose the installation option: the screen displays INS, and you select from T1, T2, T3, T4 or T5 according to how the unit is connected to the building.
5. Configure additional options, if required by the project.
6. Installation complete.

This point 4 deserves closer attention. The five configurations correspond to distinct connection modes—the unit completely independent, connected to the return of a central system, interlocked with the blower, and so on. Choosing the wrong configuration does not cause a visible failure: the unit works, it simply works poorly, and no one notices for years.

Motorized balancing dampers

The unit incorporates its balancing dampers, electronically controlled rather than adjusted by hand. The result is not merely a time saving during installation: it is a balance that is maintained over time.

A mechanical damper properly adjusted in 2020 remains set to the position in which it was left. It does not compensate for the gradual fouling of the core, a loaded filter, or an outdoor grille partially blocked by snow. Electronics, on the other hand, measure continuously and adjust.

What technology does not replace

We would be dishonest to suggest that self-balancing takes care of everything. Three things remain entirely in the installer’s hands, and the unit will never correct them:

• The duct layout. A unit balancing itself in a constricted network will balance at a low airflow. It will correctly do what it is asked to do, but the house will be under-ventilated.
• Choosing the target airflow. The unit does not know the number of bedrooms or occupants. We are the ones who enter the value.
• The T1 to T5 configuration. No automation can determine how the unit is connected to the rest of the building.

Electronics eliminate operational errors. They do not eliminate design errors.

The rest of the installation in Mercier

ECM PMSM motors: the real energy-efficiency gain

The unit runs on ECM PMSM motors—permanent-magnet motors with electronic commutation. The difference from a traditional PSC motor is substantial.

A PSC motor has two or three fixed speeds. To obtain an intermediate airflow, it must be mechanically restricted, which wastes energy. An ECM motor continuously modulates its speed and consumes only what the requested airflow requires.

Specifically: 110 W for this unit, with continuously adjustable airflow. By comparison, several PSC-motor units of equivalent capacity consume 140 to 160 W at high speed, with no ability to modulate between stages.

On a unit that runs continuously all year, the difference adds up.

A selectable airflow from 35 to 130 cfm

Here is the most useful consequence of this architecture for the homeowner: you choose the airflow to the exact number.

On a conventional unit, you choose a speed—low, high, or one of three stages—and the resulting airflow depends on the ductwork. Here, you enter the desired value in cfm, and the electronics adjust the motors to reach and maintain it.

For this Mercier residence, this allowed us to set a target corresponding to the home's actual continuous ventilation needs, without rounding up “just in case.” An air exchanger running at 65 cfm rather than the default 95 means conditioned air that is not unnecessarily exhausted outdoors.

Filtration: MERV 8 as standard, with the option to go further

An important point, and one that goes against what we recommend for older-generation units.

Many air exchangers use a foam filter whose sole purpose is to protect the core from debris. On those units, installing a denser filter is a bad idea: it adds resistance to a unit with no way to compensate, and the airflow plummets.

The N Series is designed differently. It comes standard with a washable MERV 8 filter and accepts optional MERV 13 or HEPA media. The reason is directly related to what came before: the ECM motors and integrated airflow measurement allow the unit to compensate for the added resistance of a denser filter and maintain the setpoint airflow.

For a household sensitive to pollen or fine particles, this is a concrete benefit. For everyone, it demonstrates that filtration and airflow are no longer a trade-off that must be negotiated.

Homeshield defrosting

Defrosting occurs through recirculation, using Venmar's Homeshield system. The appliance closes the outdoor-air intake and circulates indoor air through the core to remove frost from it.

The main benefit in a Quebec winter: the process does not depressurize the building during the cycle. In a home equipped with a fireplace or combustion appliance, defrosting that draws air in through the chimney is not an inconvenience—it is a risk.

Technical data

The sound level deserves a note. 60.1 dBA at a cruising airflow rate is a laboratory-measured value, taken in the immediate vicinity of the appliance. In an enclosed room, behind a door, it feels quite different. But the figure remains useful for comparing two models with each other—provided they are compared at the same airflow rate, which product literature often fails to specify.

Suspension and Placement

The appliance is installed high up, in a wall recess, away from living areas. The cabinet accommodates two mounting methods: chain suspension, supplied with the appliance, or wall brackets.

The choice depends on the available structure. In a recess where the studs are accessible and easy to locate, the wall bracket provides a stable base and frees up the space above for routing the ducts. Where the ceiling is open and the framing is accessible, chain suspension isolates vibrations more effectively.

In both cases, the rule does not change: the anchoring must be into the framing, never into the drywall alone. An appliance of this size that comes loose will take the ducts, drain, and control module with it.

The front clearance was verified before installation. The door must open fully to remove the core and filter, and the side-mounted control module must remain readable and accessible without disassembling anything.

Condensate drainage

The drain line runs from the bottom of the cabinet, forms a visible loop beneath the unit, and then reaches the drain point through an intermediate fitting.

This loop is not excess tubing that was cut poorly. It is the trap that prevents air from circulating through the drain line. Without it, the line becomes a path for unwanted airflow that skews the unit's measurements—and on a platform that self-balances based on those measurements, the effect is doubly detrimental.

Insulated flexible ducts

The outdoor connections use vapor-barrier-insulated flexible duct, with wide bends and clamps tightened at the collars.

On a unit with integrated airflow measurement, the quality of the duct installation becomes directly apparent: the airflow test will show a lower maximum if the duct system is poorly installed. In a sense, this is integrated quality control—the unit tells the installer how good their own work is.

Decoding the A130H65RT model number

The Venmar nomenclature is descriptive, and it is worth reading:

• A — the product family
• 130 — the nominal airflow, in cubic feet per minute
• H — HRV, heat recovery ventilator (an E would indicate an energy recovery ventilator, which also transfers moisture)
• 65 — the sensible heat recovery efficiency class
• T — the position of the collars, here on top (an S would indicate side connections)

Two units whose model numbers differ only by the final letter have exactly the same performance. They simply cannot be installed in the same space. Choosing the wrong letter means ending up with ducts running in the wrong direction in a space that is too narrow.

The mistakes we see with these units

• Not rerunning the airflow test after modifying the ducts. The unit continues to target an airflow calculated for a duct system that no longer exists.
• Choosing the wrong T1 to T5 configuration. There may be no immediate symptoms, but operation will remain inadequate over time.
• Believing that self-balancing eliminates the need for a properly designed duct system. It only correctly carries out the conditions it is given.
• Setting the maximum airflow too conservatively. You over-ventilate, heat the outdoors, and dry out the air in January.
• Neglecting the wall-mounted control module. If it becomes illegible or inaccessible behind a duct, we lose the full benefit of the integrated diagnostics.

Maintenance

• Every three months: remove and wash the MERV 8 filter, or replace it if MERV 13 or HEPA media was selected.
• Once a year, in the fall: remove the polypropylene core, soak it in mild soapy water, rinse thoroughly, and dry completely.
• After every thaw: inspect the outdoor vents, where frost can easily form again.
• After any duct modifications: repeat the airflow test. This is the most important and most frequently overlooked instruction.

Financial assistance: what to confirm

A standalone air exchanger generally does not qualify for direct financial assistance in Quebec. Mechanical ventilation is, however, considered when evaluating a Rénoclimat project if it accompanies insulation or building-envelope airtightness work. Program parameters change periodically, so we recommend confirming eligibility before including an amount in the budget.

Our projects in Montérégie

We serve the entire Roussillon and Haut-Saint-Laurent regional county municipalities, as well as the Longueuil agglomeration:

• Châteauguay: replacement of a unit with manual dampers by an electronically balanced platform, while retaining the existing duct network.
• Sainte-Martine: upgrade of a duct network whose resistance limited the maximum airflow achievable by the new unit.
• Léry: complete rework of an installation configuration that had been poorly selected during the initial commissioning.
• Saint-Isidore: addition of a MERV 13 filter media to an ECM motor platform, with airflow verification after the change.

Let's talk about your project

At AirGreen, we design, install, replace, and maintain residential and commercial ventilation systems in Montreal, Laval, Longueuil, the North Shore, and the South Shore. We work with both traditional manual-balancing platforms and units with integrated airflow measurement, and we choose based on the building, not on novelty.

If your current air exchanger has never been balanced—or if no one gave you a report at installation—that is the starting point for any serious conversation about the air quality in your home.