Installation of a Venmar AVS Solo 1.5ES air exchanger in Delson

An air exchanger is not an air purifier — unless it is configured for that purpose

This is the sentence that surprises our clients from Delson and the surrounding areas the most. They have just had an air exchanger installed, they live just minutes from Highway 30 and the railway, and they expect the unit to address fine-particle pollution as well. Then they open the cabinet door, remove the filter, and find blue foam that is rinsed with water.

This foam is not there to protect your lungs. It is there to protect the recovery core.

The project described here is a finished basement in Delson, in the area bordered by the Tortue River. We installed a Venmar AVS Solo 1.5ES, an ENERGY STAR-certified HRV, suspended in the cavity of a drop ceiling. In the photo, the unit is open: the yellow recovery core is positioned diagonally, the bilingual maintenance label is affixed to it, and the fan turbine can be seen on the right. This label explicitly mentions maintenance for MERV 13 and HEPA filters — and that is where the most useful conversation a homeowner can have begins.

What an HRV actually filters straight out of the box

The original filters in the Solo 1.5ES are washable foam filters. Their role is mechanical: to catch hair, flies, coarse dust, and dryer lint before they reach the recovery core and the fans. A clogged core loses its transfer efficiency; a turbine unbalanced by deposits makes noise and consumes more energy.

What these foams do not capture: fine PM2.5 particles, fine pollen, spores, and combustion soot. In other words, everything that truly concerns a family living near a highway corridor or cultivated fields.

The good news: mechanical ventilation still improves indoor air quality because it continuously dilutes and removes what is produced indoors — CO₂, volatile organic compounds from materials and household products, moisture, and odors. That is already significant. But this is dilution, not filtration.

The filtration trade-off: every gain comes at the expense of airflow

Improving the filtration of a ventilation system is never free. A finer filter adds static pressure to the system. This pressure reduces the unit's actual airflow, and airflow is precisely what the Code requires.

The principle, quantified for the Solo 1.5ES

The Solo 1.5ES delivers 66 to 150 CFM (low and high speed), measured at 0.4 in. of water column (100 Pa). This reference value is not insignificant: it already corresponds to a system with some resistance. If a fine filter cartridge is added without reviewing the rest, the system falls below the curve, and the airflow delivered to the bedrooms drops below the required value without anyone noticing—because the unit continues to run exactly as before.

That is why we systematically apply three rules:

1. Never replace a filter with a finer model without remeasuring the airflow. A manometer reading takes twenty minutes; ignorance lasts for years.
2. Do not compensate for a fine filter by running the fan at a higher speed continuously. This brings back the noise and wear we were trying to avoid.
3. Size the unit based on the planned filtration, not just the home's volume.

The three possible options

• Stay with washable foam. The default choice. Simple maintenance, no additional pressure drop, and assured core protection. Fresh-air filtration: minimal.
• Switch to a MERV-type pleated cartridge. At Venmar, MERV 12 pleated cartridges and HEPA filters belong to the dedicated HEPA 3100 and HEPA 4100 product lines. On newer cabinets, the core maintenance label—the one visible in our photo—explicitly calls for replacing a MERV 13 or HEPA filter every three months. The benefit is real; so is the pressure drop, and it must be accounted for during sizing.
• Add a dedicated filtration unit. Venmar's HEPA 3100 combines a heat-recovery ventilator and HEPA purification in a single cabinet, delivering 70 to 105 CFM with just one exterior penetration thanks to the Tandem transition. This is the option we recommend for clients whose primary concern is allergy- or respiratory-related, rather than forcing a standard HRV to do work it was not designed for.

For this home in Delson, the owners chose the original washable foam filter, with an upgrade to a pleated cartridge planned for the second year—after a full season of measurements, and with airflow readjustment scheduled in advance in the HVAC maintenance contract.

The Solo 1.5ES in figures

Three features of the Solo range influenced the choice for this project:

• The unit is fully reversible. The ducts can be configured on either side, allowing the unit to be adapted to the available cavity rather than the other way around. In a suspended ceiling, this is decisive.
• The pressure taps and balancing dampers are integrated. Balancing is done without drilling into the ductwork.
• Operation is particularly quiet, which matters when the unit is suspended directly above a family room.

The suspended ceiling: the silent enemy of maintenance

In the photo, the unit is housed between the joists, above the acoustic tiles of a suspended ceiling, held in place by chains and hooks. The blue vapor barrier on the perimeter wall is still visible. This is a very common configuration in finished basements in Delson, Candiac, Saint-Constant, and Sainte-Catherine—and it is a configuration that ruins maintenance if poorly executed.

The problem, simply put

A suspended ceiling provides access to everything. It also creates the illusion that access will always be easy. But three things happen in the years that follow:

• recessed lights, a plumbing duct, or a network cable take up the space in front of the unit door;
• the tiles age and become brittle, and no one wants to remove them anymore;
• the homeowner simply forgets that there is a unit up there.

What we do differently

• We reserve the door-opening path and mark it. On a Solo, the door opens at the front and the core is removed horizontally: you need the length of the core in front of the unit, not just the tile width.
• We identify the tiles to be removed with a discreet marker on the ceiling structure, on the cavity side.
• We install the chains with isolation springs at the anchor points. A unit rigidly attached to a joist above a family room transmits its vibrations through the upstairs floor; decoupling costs a few dollars and makes a difference every day.
• We leave the drain accessible. The Solo 1.5ES produces condensate during the cold season. The hose is installed with a continuous slope and a primed trap loop, and the connection point remains visible through an identified removable tile.

The system: 6-in. nozzles and exterior outlets

The four 6-in. round nozzles were fitted with insulated ducts secured with straps. Outside, we used an IN2000 cap set (1607100): two 6-in. caps with double mounting collars, installed with the code-required spacing between the intake and exhaust, away from the dryer outlet and plumbing vent.

In systems where exterior wall space is limited—a shared wall, a narrow facade, or recent siding that the client does not want pierced twice—the Tandem (04321) transition allows the intake and exhaust to be combined into a single penetration. We systematically verify that the selected arrangement is acceptable to the authority having jurisdiction: requirements vary from one municipality to another on the South Shore as well as the North Shore.

Inside, the supply grilles were fitted with 5- and 6-in. Whisper registers, whose geometry limits whistling at high airflow—a detail that often determines whether the homeowner will leave their air exchanger running or eventually turn it off.

Balancing: the part of the work you will never see

Balancing is performed with a Magnehelic pressure gauge (0 to 0.50 in. water column scale) connected to the integrated pressure ports, using flow meters corresponding to the nozzle diameters. We adjust supply and exhaust to match, then record the values.

The manufacturer is explicit about the issue, and it is worth stating it plainly:

• Negative pressure: the house draws in unconditioned air through leaks, increasing energy costs, encouraging mold growth, and potentially causing combustion products from an appliance connected to a chimney to backdraft.
• Positive pressure: warm, humid air is pushed into the walls and insulation, where it condenses—causing mold, mildew, and rot—in addition to heat loss.
• Balanced pressure: the supply equals the exhaust. This is the only acceptable condition, and it requires measurement.

The controls available for the Solo series

• Altitude (40440): programmable LCD control with SMART mode that automatically adjusts operation. This is the one we recommend when the client wants to set the unit once and forget about it.
• Deco-Touch (40395): stop, minimum/maximum speed, 20 min/h intermittent mode, recirculation, dehumidistat override.
• Illuminated 20/40/60-minute push button (03364): compatible with Solo models, for installation in bathrooms.
• Dehumidistat (11297) and 60-minute mechanical timer (00910) as options.

Here, we selected a main control in the kitchen and a 20/40/60 button in each of the two bathrooms.

Incentives: the amount and the condition that can trip you up

The Rénoclimat program provides 500 $ for installing or replacing a heat-recovery ventilation system. Two requirements govern it.

The unit must be listed in section 3 of the Home Ventilating Institute (HVI) certified product directory. Venmar has been an HVI member since 1991, and all its AVS units are HVI-certified, which we verify in the file.

Most importantly, eligibility for the incentive depends on an improvement in the EnerGuide rating between the pre-retrofit and post-retrofit evaluations. Adding an HRV alone to an existing home increases energy consumption: without energy-efficiency measures carried out as part of the same project, the rating may deteriorate and the incentive may be refused, including for ventilation. The correct sequence is therefore: pre-retrofit evaluation, then HVAC installation combined with insulation or air sealing, followed by a post-retrofit evaluation. We confirm this point with the program advisor before including it in a quotation.

The maintenance schedule we provide to the customer

1. Rinse washable foam filters every two to three months. Use warm water and mild soap, and let them dry completely before reinstalling them.
2. Clean the heat-recovery core once a year, first with a vacuum and then with warm, soapy water.
3. Replace an MERV 13 or HEPA cartridge every three months, if the system is equipped with one—and have the airflow readings taken again when a cartridge is first installed.
4. Inspect the exterior caps in spring: blocked screens, nests, or residual ice.
5. Never lubricate the motors. They do not need it, and oil attracts dust.

At AirGreen, we install, replace, balance, and maintain residential ventilation systems in Delson, Longueuil, throughout the South Shore, as well as in Montreal, Laval, and the North Shore. If filtration is your priority rather than simple air exchange, tell us before the unit is selected: this requirement affects sizing and is difficult to correct once the ducts are installed.