Installation of a Lifebreath RNC5-TPD air exchanger in Blainville

Installation of a Lifebreath RNC5-TPD air exchanger in Blainville

When the air in a Blainville home goes round and round: the day we built a fully dedicated ventilation network

There are homes where the problem is not the heating or the air conditioning, but simply the fact that the air has nowhere to go. This one, a two-story single-family home in the Chambéry area, in Blainville, was the perfect example. Windows fogged up halfway from mid-December onward, cooking odors lingered on the second floor until the next morning, and the primary bedroom felt stuffy upon waking. The owners had replaced their windows, added insulation in the attic, and sealed air leaks in the basement. Each improvement made the home more airtight, and each improvement made the problem worse.

This is the logic we explain every week to clients in Blainville, Sainte-Thérèse, Boisbriand, and Rosemère: a tightly sealed home without mechanical ventilation is not a high-performance home; it is a home sealed in with its own air. We therefore installed a Lifebreath RNC5-TPD air exchanger, with a fully dedicated duct network, Techgrilles 99-EAG5 in every room served, and a 99-DET01 wall timer in the main bathroom—the one visible in the photo, with its three 20-, 40-, and 60-minute indicator lights.

Why an HRV instead of a simple exhaust fan

A bathroom fan expels stale air. It does not replace it. In January, in the Laurentians, every cubic foot of warm air expelled is replaced by a cubic foot of outdoor air at -22 °C entering through the first crack it finds—often in the basement, often near the combustion appliance. This is inefficient from an energy standpoint and can sometimes be dangerous.

A heat recovery ventilator (HRV), or air exchanger, does something entirely different. It expels a flow of stale air and simultaneously introduces an equivalent flow of fresh air, crossing the two streams in a recovery core. Heat passes from one stream to the other; the two airflows never mix. In practical terms, the fresh air entering these Blainville clients’ home is preheated by the air they have just expelled, before it even reaches the first grille.

What the RNC5-TPD core actually does

The Lifebreath RNC5-TPD uses a patented cross-flow core made of thermally conductive aluminum. The HVI-certified figures, at 0 °C:

• ASE (apparent sensible effectiveness): 68% at 66 CFM
• SRE (sensible recovery efficiency): 61% at 85 CFM
• SRE maintained at 61% at -25 °C, at 76 CFM

This last point deserves attention. Many units advertise impressive figures at 0 °C and collapse when temperatures actually drop. Here, the performance at -25 °C is identical to that measured at 0 °C. For a house on the North Shore, where a week at -25 °C is nothing unusual, this is exactly the figure that matters.

Aluminum has another advantage, less glamorous but very practical: it can be washed. The core is removed from the front, rinsed under lukewarm water, dried, and placed back into the cabinet. A paper or enthalpy membrane core, on the other hand, must be replaced. This is also why Lifebreath offers a lifetime warranty on the heat recovery core and five years on replacement parts.

Calculating the airflow before purchasing the unit

We never sell a heat recovery ventilator before performing the calculation. The Quebec Building Code determines the total ventilation capacity by adding the required airflow for each room. For this house:

The RNC5-TPD delivers 156 CFM at 0.2 in. of static pressure and 149 CFM at 0.3 in. We therefore had enough capacity to reach 117 CFM without running the unit at full speed continuously—a crucial condition for keeping it quiet and its energy consumption low. At reduced speed, the unit draws 69 W; at high speed, 147 W, on a standard 120 V circuit.

Choosing an appliance that is too small forces it to run constantly at maximum output: noise, motor wear, and actual airflow below expectations as soon as the filters become loaded. Choosing an appliance that is too large for a small house dries out the air in January and drives up the heating bill. This is one of the mistakes we correct most often during our service calls in Laval, Longueuil, and on the South Shore.

The project, step by step

Suspension and service clearance

The unit weighs 51 lb (23 kg) and measures 17 1/4 x 22 3/4 x 14 in. We suspended it from the basement joists using the four straps and S-hooks provided (99-80-102), while maintaining the manufacturer’s recommended 25-inch front clearance. This clearance is not a matter of aesthetics: without it, neither the core nor the filters can be removed, and HVAC maintenance becomes a chore the owner eventually gives up on. We have seen perfectly functional units condemned by a suspended ceiling installed six months later.

Condensate drains

The TPD model produces condensate. Two 1/2-inch (12 mm) fittings were connected to the basement drain outlet with a properly filled trap loop. An empty trap allows sewer odors to rise into the unit and then throughout the house, after which the owner blames the air exchanger as the source of the problem. We systematically take a photo of our traps.

The dedicated ductwork: collection and distribution

The RNC5-TPD is equipped with four 5-inch (125 mm) oval collars, with balancing dampers integrated into each collar.

• Stale-air collection: two bathrooms, the kitchen (dedicated grille away from the stove, never connected to the hood), and the laundry room.
• Fresh-air distribution: primary bedroom, two secondary bedrooms, living room, and finished basement.
• Terminations: 5-inch Techgrilles 99-EAG5, whose adjustable central cone allows the airflow to be adjusted room by room without opening the ceiling, mounted on 99-TM5 Terminator fittings.
• Exterior intakes: 99-185 caps with 12-inch wall sleeves and 1/4-inch mesh, positioned more than 6 ft apart and away from the dryer outlet and boiler-room vent.

The classic mistake on this type of project is placing the fresh-air intake under a gallery or near a parking area. The unit then operates perfectly—and diligently distributes exhaust fumes throughout the bedrooms. We had to move the intake shown on the plans two metres toward the side wall, away from the garage entrance.

Recirculation damper defrost

The suffix TPD refers to recirculation damper defrost. When the outdoor temperature drops below the critical threshold, the unit closes the outdoor air intake and recirculates indoor air through the core to defrost it, without ever shutting off the home's ventilation. The TPF version defrosts by stopping the fan: it costs less, but interrupts the supply of fresh air during the cycle. For a North Shore winter, we almost always recommend the recirculation damper.

Balancing: the step no one sees that determines everything

An improperly balanced air exchanger is a device that costs money without solving anything. If the exhaust airflow exceeds the supply airflow, the house becomes depressurized: it draws air in through leaks, the crawl space, and, in the worst case, through the flue of a combustion appliance. If the supply exceeds the exhaust, the house becomes pressurized and pushes indoor moisture into the walls, where it condenses.

We therefore balanced the system using a digital manometer and the balancing ports at the door of the RNC5-TPD, which allow both airflows to be measured without drilling into the ducts. Result recorded during commissioning: 118 CFM supply, 118 CFM exhaust, at the selected continuous operating speed.

Three controls, three uses

• 99-DET01 — the 20/40/60-minute timer installed in the main bathroom, the one shown in the photo. Three indicator lights, one button, and connection to three 20-gauge wires (100 ft. maximum). Press it once, and the unit switches to high speed for the selected duration, then automatically returns to its continuous setting.
• 99-DET02 — the same function, wireless, with a range of approximately 40 ft., useful when running a wire through a finished ceiling would cost more than the accessory.
• 99-BC04 / 99-DXPL02 — the main controls, with 20-minute ventilation / 40-minute off, 20-minute ventilation / 40-minute recirculation, and continuous ventilation modes.

We programmed the 20/40 mode for continuous low-speed ventilation during the cold season, switching to continuous high-speed operation in the spring and fall, when outdoor humidity is higher.

Grants: what to know before doing your calculations

We prefer to be clear rather than optimistic. As of today, an air exchanger installed alone in an existing home is not eligible for a direct subsidy comparable to those offered for a heat pump by LogisVert or Rénoclimat. However, an HRV is required in Novoclimat-certified construction, and the Rénoclimat energy assessment takes the home’s airtightness and ventilation as a whole into account—which changes the picture for clients who combine insulation, air sealing, and an HVAC installation in the same project. We always verify eligibility for the specific file before mentioning it in a quote.

What we have learned from other similar projects

On the air exchangers we replace in Blainville, Mirabel, Terrebonne, and Bois-des-Filion, four issues keep coming up:

1. The unit connected only to the furnace return. A simplified method accepted in certain cases, but one that provides no ventilation at all when the furnace fan is off.
2. No documented balancing. No one knows how much airflow leaves the unit or how long it has been that way.
3. Crushed or overly long flexible ducts. Every tight bend adds static pressure and reduces airflow; we limit duct lengths and support the flexible ducts.
4. Filters that are never washed. The RNC5-TPD filters are washable and take three minutes to clean. We recommend rinsing them every two to three months and washing the core once a year.

The result at our clients’ home in Blainville

Three weeks after commissioning, in the middle of February, the second-floor windows were dry in the morning. Indoor relative humidity, which had fluctuated between 55 and 60% before the work, stabilized between 35 and 40%. Cooking odors now disappear in about twenty minutes. And the house is no colder: that is precisely the role of the heat-recovery core.

At AirGreen, we design, install, and balance residential ventilation systems throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore. Every air exchanger we install leaves with its airflow rates measured, documented, and explained to the homeowner. If the air in your home keeps circulating in circles, contact us: we’ll start with the calculations, not the catalogue.