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Les conséquences réelles et coûteuses d’un échangeur d’air mal réglé en hiver à Montréal
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The Real and Costly Consequences of a Poorly Calibrated Air Exchanger in Winter in Montréal

A poorly adjusted air exchanger: a silent but serious risk for Montréal homes

At AirGreen, we’re often called in to diagnose issues with humidity, condensation, or thermal comfort in homes across Montréal, especially during the winter. More often than not, the culprit isn’t the heat pump or central heating system—it’s a poorly calibrated air exchanger. This kind of improper setup—often overlooked during the initial installation—can lead to costly, initially invisible, but long-term serious consequences.

Why air exchanger calibration is critical in winter

During winter, Montréal homes are generally tightly sealed to retain heat. In this context, an air exchanger must:

  • Expel stale air without causing excessive negative pressure

  • Bring in fresh, tempered air without cooling down the rooms

  • Maintain stable humidity levels, ideally between 35% and 45%

  • Prevent condensation on windows, walls, or inside the ducts

A poor balance between incoming and outgoing air, or an airflow rate that’s too high or too low, quickly leads to structural issues, inflated energy bills, and poor air quality.

Common consequences observed by AirGreen in Montréal homes

Here are the most frequent mistakes and their direct repercussions:

  • Humidity too low (under 30%): dry throat sensation, sinus irritation, cracking hardwood floors, cracks in moldings.

  • Humidity too high (over 50%): window condensation, mold, deterioration of finish materials, lingering odours.

  • Unstable indoor temperature: cold air entering the home improperly, forcing the heating system to overwork.

  • Excessive ventilation noise: whistling, vibrations, or buzzing due to unbalanced or oversized ductwork.

  • Mold growth in ducts or air exchangers: caused by poor air renewal or stagnant humidity.

Real examples of AirGreen interventions in Montréal

Montréal – Rosemont
A couple complained about cracks in door frames and a constant feeling of dry air. We discovered the HRV air exchanger was set at maximum speed around the clock. After adjusting the airflow and installing a humidity sensor, comfort was restored and indoor humidity stabilized at 38%.

Ahuntsic – Renovated duplex
Mold spots appeared on the bathroom ceiling, even with a fan in use. The air exchanger wasn’t effectively removing moisture. AirGreen installed a Fantech VHR150 ERV model with a programmable timer, calibrated to the household’s real needs. Result: complete mold removal and much healthier air.

Hochelaga-Maisonneuve – Modern condo
The homeowner noticed fogging on all windows as soon as the temperature dropped below -5°C. Poor placement of fresh air intake ducts, combined with improperly set airflow, was the root cause. We repositioned the ducts, insulated the vulnerable sections, and calibrated the system precisely. Since then, no more condensation.

Brands and models frequently recalibrated or replaced by our teams

Some installations require professional tuning, even with high-quality equipment:

  • Venmar EVO5 500 HRV: excellent model, but often poorly balanced straight out of the factory.

  • Lennox HRV700 or ERV300: needs fine-tuning based on actual square footage.

  • Fantech VHR150 ECM: very efficient, but highly dependent on proper duct insulation.

  • Lifebreath MAX Series: must be synchronized with central heating to avoid imbalance.

All of these models are eligible for Hydro-Québec’s LogisVert rebates, provided they are properly installed and calibrated.

How to tell if your air exchanger is poorly calibrated

Here are a few red flags to watch for:

  • Indoor air feels too dry or too humid despite stable heating

  • Frequent condensation on windows during winter

  • Odours linger even after ventilation

  • Ventilation is excessively noisy or runs non-stop

  • Mold appears in well-maintained rooms

What AirGreen does to fix these issues

  • Full diagnostic of your existing HVAC system, including airflow analysis, humidity readings, and heat loss calculations

  • Precise recalibration using professional instruments to balance airflows

  • Insulation of exposed ducts to prevent heat loss and condensation

  • Installation of automated humidity controllers, synced with the main system

  • Inspection and repositioning of vents when necessary

Each intervention includes documentation and a detailed report with recommendations.

A poorly calibrated exchanger is expensive. Good maintenance pays off.

At AirGreen, we believe that an air exchanger’s performance depends just as much on its calibration as on its installation. A poorly adjusted system can ruin a perfectly insulated home. That’s why we offer calibration, maintenance, and inspection services throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore.

Call on our experts to turn your ventilation system into an asset for your health, comfort… and savings.

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