Optimizing indoor air quality without wasting energy
At AirGreen, we spend a great deal of our time working in homes and buildings across Montreal, Laval, Longueuil, as well as the North Shore and South Shore, handling installations, repairs, and maintenance of air exchangers. And over the years, one critical mistake keeps coming back in almost every household: the improper use—or complete lack of use—of their air exchanger.
This oversight, although simple to correct, can have major consequences on indoor comfort, energy consumption, humidity levels, and even the respiratory health of the occupants. This article will explain in detail what this mistake is, how to avoid it, and why regular HVAC maintenance is essential to get the most out of your ventilation system.
Why an air exchanger is essential for indoor comfort
Before we dive into the mistake itself, it’s important to understand the vital role of an air exchanger. This device is an integral part of any modern HVAC system in Quebec, especially in highly insulated homes like those in Montreal or Longueuil, where airtightness leads to the buildup of humidity, pollutants, and CO₂.
An air exchanger allows you to:
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Renew indoor air by removing stale air (rich in humidity, odors, CO₂) and replacing it with fresh air from outside.
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Recover heat (or cooling) from outgoing air using a core exchanger to preheat or precool the incoming air.
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Reduce the risk of mold, allergies, and condensation.
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Improve the energy efficiency of your overall heating or cooling system.
Mistake #1: Leaving your air exchanger on “continuous” mode or turning it off entirely
Most of the clients we meet in Laval, Sainte-Julie, Terrebonne, or Brossard are doing one of the following two things:
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They leave their air exchanger running 24/7 at full speed, thinking constant air renewal means better air quality.
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They turn it off completely, especially in winter, to “save” on their electric bill.
Both approaches are problematic.
Leaving the unit on full speed continuously: why it's a bad idea
This leads to:
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Unnecessary energy consumption, since the unit runs constantly, even when it’s not needed.
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Significant heat loss, especially in winter, as even with a heat recovery core, the system still brings in very cold air.
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Premature wear and tear on the motor and core exchanger.
Turning the exchanger off: a common trap
This is probably the most dangerous mistake. When an air exchanger is turned off:
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Humidity builds up, especially in bathrooms and the kitchen.
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CO₂ levels rise quickly, which can affect concentration and sleep quality.
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Indoor pollutants (VOCs, fine particles, allergens) remain trapped in your living space.
The solution: using the right modes and regular maintenance
At AirGreen, we recommend a custom approach, based on your home’s layout, occupancy, and your habits.
Here are some best practices to follow:
1. Understand the modes on your air exchanger
Most modern units (like models from Venmar, Lifebreath, Fantech, or Broan) offer several modes:
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Intermittent mode (20/40): runs for 20 minutes every hour. Sufficient for most homes.
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Temporary high-speed mode: ideal after showering or while cooking.
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Continuous low-speed mode: to be used during periods of high humidity.
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Automatic mode (with sensors): detects humidity or CO₂ and adjusts airflow accordingly.
2. Clean filters and the core exchanger every 3 to 6 months
A clogged filter reduces system efficiency and increases power use. Our AirGreen technicians provide professional HVAC maintenance that includes:
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Cleaning or replacing washable filters.
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Disassembling and cleaning the core exchanger.
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Inspecting ducts and checking airflow.
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Adjusting fan speeds seasonally.
3. Adjust the settings with the seasons
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In winter: use intermittent or smart mode to avoid drawing in excessive cold air while maintaining healthy ventilation.
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In summer: more flexibility, but keep an eye on humidity levels.
Real-life example: service call in Laval for a young family
Recently, we visited a couple with two young children in Chomedey, Laval. Their Venmar EVO5 air exchanger was running nonstop at full speed, even in the winter. The result:
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Complaints of cold drafts in the living room.
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A 15% higher electricity bill compared to the previous year.
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Premature wear on internal components.
Here’s what we did:
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Reprogrammed the control panel to switch to 20/40 mode.
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Performed a deep cleaning of the dirty core exchanger.
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Gave clear instructions on how to use high-speed mode only in the bathroom when needed.
Since then, they’ve enjoyed optimal comfort, improved air quality, and lower energy costs.
Common mistakes to avoid with your air exchanger
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Ignoring visible dirt on vents or filters.
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Assuming an air exchanger replaces an air purifier (they’re complementary).
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Letting the system run without an annual check-up.
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Misplacing the exterior vents, which can lead to moisture re-entry.
Why trust AirGreen?
At AirGreen, we combine technology, real-world experience, and a customer-first mindset. Our certified technicians respond quickly across Montreal, Longueuil, Laval, and throughout the North Shore and South Shore for:
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Installation of centralized or decentralized air exchangers.
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Comprehensive HVAC seasonal maintenance.
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Personalized advice tailored to your home, your routines, and your air quality needs.
We use professional diagnostic tools to measure airflow, relative humidity, CO₂ levels, and we walk you through the best settings for your system.
What you can do today
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Check your air exchanger’s current mode.
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Schedule a complete maintenance service if it’s been more than 6 months.
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Contact us for a free analysis of your HVAC system.