Installation of a Greentek PROFILE 1.2E-D-EC air exchanger with a T4 timer in Villeray–Saint-Michel–Parc-Extension

The Only Button the Occupant Will Ever Press

The photo from this project shows neither ductwork, a core, nor a housing. It shows a white wall plate with three indicator lights—20 min, 40 min, 60 min—and a button marked with a propeller. This is Greentek's T4 timer, and in practice, it is the complete ventilation-system interface for the person living in the home.

A properly configured air exchanger runs continuously at low speed without anyone having to manage it. The only action the occupant takes is pressing a button when leaving the shower. The timer switches the unit to its maximum airflow for the selected duration, then automatically returns it to the programmed setting. No switch left in the on position, no setting to reset.

In the duplexes and triplexes of Villeray, Saint-Michel, and Parc-Extension, this detail matters more than it may seem.

The Problem of Windowless Bathrooms

Montreal plexes built between 1920 and 1960 share a common layout feature: the bathroom is often located in the center of the home, wedged between the hallway and a bedroom, with no exterior wall and therefore no opening window. In Parc-Extension homes, where residential density is among the highest in the country and lots are narrow, this layout is the rule rather than the exception.

Without a window, mechanical ventilation is the only option. And an ordinary exhaust fan in a home with a renovated envelope creates negative pressure, drawing replacement air through the shared stairwell, crawl space, or foundation cracks—with everything those pathways carry.

The tenant or homeowner in the neighboring unit then smells the cooking odors from the adjacent home without understanding why. This is the most frequent type of call we receive in this area.

Why choose an ERV rather than an HRV for this home

This is the least well-explained distinction in the field, and the one that determines whether the unit will solve the problem or create another one.

The HRV transfers heat only

A heat recovery ventilator (HRV) recovers heat from outgoing stale air and transfers it to incoming fresh air. The moisture, however, goes outside with the stale air. It is the right choice in a home suffering from excess humidity in winter: condensation on windows, a damp basement, mold in cold corners.

The ERV transfers heat and moisture

An energy recovery ventilator (ERV) uses a core that exchanges both heat and water vapor. In winter, some of the indoor moisture is retained in the dwelling instead of being expelled; in summer, moisture from the outdoor air is partially removed before it enters. It is the right choice in a dwelling that becomes too dry in winter—an irritated throat, static electricity, splitting wood floors—and uncomfortably humid in July.

The dwelling in question here fell into the second category. Electric heating, no significant moisture source, and an owner who used two portable humidifiers from January to March. Installing an HRV would have worsened the winter dryness. The PROFILE 1.2E-D-EC is an ERV.

We ask this question before anything else, for every ventilation quote. A perfectly installed unit of the wrong type is still the wrong unit.

The Greentek PROFILE 1.2E-D-EC specifications

• Type: ERV (energy recovery, cross-flow core)
• Airflow range: 40 to 129 cu. ft./min at 0.4 in. water column
• Connections: 5 in., side-mounted
• Installed depth: 10 in.
• Weight: 35 lb
• Power supply: 120 V, 3 A max
• Power consumption: 23 W at low speed, 74 W at high speed
• Fan efficiency: 2.2 cu. ft./min per watt
• Sensible recovery: 77% at 0 °C
• Integrated motorized outdoor air damper
• High-efficiency EC motors, ENERGY STAR certified
• Filtration: MERV 3 standard, MERV 8 or MERV 13 replacement
• No drain required
• Warranty: 7 years on the motors, 5 years on the parts and core

Three of these points carried more weight than the others in the decision.

No drain required

This is the constraint that eliminates half the units in an apartment dwelling. A Villeray duplex does not have a floor drain on the second floor, and routing a condensate line to the washer’s vertical drainpipe—when there is one—often means cutting through finished walls. The PROFILE’s energy-recovery core generates no condensate that needs to be drained. The problem disappears instead of being worked around.

Ten inches deep

The unit fits in a shallow closet or above a dropped ceiling without reducing the clear height of a habitable room. In a 1,000-square-foot dwelling where every closet matters, the difference between 10 and 15 inches determines whether the project is feasible.

EC motors and 23 watts in continuous operation

The unit runs continuously. At 23 W on low speed, its annual consumption remains marginal on a Hydro-Québec bill. Versions with conventional motors consume more than twice as much for the same service.

Defrosting by shutting down the supply fan: what you need to know

Below approximately -5 °C, any appliance of this type must prevent frost from blocking its core. The PROFILE uses supply-fan shutdown: the fresh-air supply temporarily stops while exhaust continues and defrosts the core.

It is a simple, reliable mechanism with no fragile moving parts. Its drawback: during those minutes, the dwelling is no longer supplied with fresh air, and exhaust-only operation places it under slight negative pressure. The motorized damper in the -D version specifically limits this effect by closing the outdoor-air intake, which also prevents cold air from backdrafting by gravity when the unit is off—a common phenomenon in a plex exposed to wind.

When continuous fresh-air supply is the priority, we instead recommend the SOLACE series, whose defrosting occurs through internal recirculation, without interruption. This is a trade-off to discuss before purchase, not afterward.

Timer placement, and why it matters

The T4 running at full speed for 20, 40, or 60 minutes serves two purposes: removing shower humidity before it migrates into the corridor, and removing cooking odors that escape the range hood.

We usually install two timers: one outside the bathroom, on the corridor side, and one near the kitchen. Placing it outside the bathroom is not an arbitrary detail—in a windowless room where steam saturates the air, a wall control installed inside ages poorly.

The duration should be chosen according to actual use. Twenty minutes are enough after a short shower in a one-person dwelling; sixty minutes are more suitable for a bathroom used successively by four occupants in the morning.

The mistakes we correct in plexes in this area

1. Replacing a bathroom fan with another bathroom fan. The problem was never the exhaust: it was the lack of compensating fresh-air supply.
2. Choosing an HRV in a home that is already too dry in winter. The unit works perfectly, yet comfort still deteriorates.
3. Leaving the unit on a simple switch. It ends up either always on or always off. A timer and continuous-control setting are available to avoid this binary choice.
4. Neglecting airflow balancing. Supply and exhaust must be within 10% of each other, measured at the designated balancing ports. In a plex, an unbalanced unit merely moves air—and odours—between homes.
5. Forgetting about filters. The original filter is MERV 3. We recommend upgrading to MERV 8 or MERV 13 in homes along the busy arteries of Villeray and Saint-Michel, with a check every three months.
6. Installing the unit against a shared bedroom wall. Structural noise is addressed before installation, not afterward.

Our approach to ventilation in Montreal plexes

At AirGreen, we design and install residential ventilation systems in Villeray–Saint-Michel–Parc-Extension, Rosemont, La Petite-Patrie, and Ahuntsic, as well as throughout Montreal, Laval, Longueuil, the North Shore, and the South Shore. The multi-unit buildings in these neighbourhoods have requirements that single-family homes can ignore: no drain available on upper floors, shared walls everywhere, limited closet space, and air transfers between units that an approximate installation amplifies instead of correcting.

Our method begins with a question rarely asked during the quoting process: is this home too humid or too dry in winter? The answer determines the type of equipment, and everything else follows from there—sizing, placement, duct routing, and controls.

For an evaluation of HVAC installation, the addition of an air exchanger, or the replacement of a ventilation system in Villeray, Saint-Michel, Parc-Extension, or elsewhere in Greater Montreal, our team visits the property, takes measurements, and proposes a solution suited to the actual home.