What we uncovered while analyzing indoor air quality in ordinary North Shore homes may surprise (and alarm) you
In the HVAC industry across Montréal, Laval, Longueuil, South Shore and North Shore, the focus is often on the visible components: heat pumps, wall-mounted air conditioners, ductwork, and filters. Yet the air we breathe inside our homes is often more polluted than the air outside. At AirGreen, we decided to put this reality to the test by conducting a thorough study in 20 homes located on the North Shore.
The results were undeniable: in 17 out of 20 residences, indoor air quality was significantly worse than outdoor air. In this article, we share the full details of our test, the causes we identified, the health consequences involved, and the practical solutions implemented by our HVAC experts.
Why did we conduct this study on the North Shore?
Our teams frequently work in Boisbriand, Blainville, Terrebonne, Mirabel, and Mascouche, installing air exchangers and performing HVAC maintenance. A recurring pattern caught our attention: clients complaining of headaches, chronic fatigue, or persistent odors—even though their homes appeared clean and well-ventilated.
This led us to scientifically measure the levels of:
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Fine particles (PM2.5)
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Formaldehyde and volatile organic compounds (VOCs)
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CO₂ concentration
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Relative humidity
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Presence of invisible mold spores
Tests conducted on-site, under real living conditions
We used certified portable air analyzers over 72 consecutive hours in each of the selected homes. All homes had standard ventilation systems, but only 5 had a modern air exchanger (ERV or HRV with energy recovery capabilities).
Here’s what we discovered:
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85% of homes had CO₂ levels exceeding 1,200 ppm, especially at night—clear evidence of insufficient air renewal.
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65% showed high VOC levels, mostly due to building materials, paint, furniture, or household cleaning products.
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In 9 homes, microscopic mold spores were detected—even though no visible mold was present.
The consequences on the occupants’ health
Clients reported similar symptoms:
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Morning fatigue despite a full night's sleep.
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Eye, throat, or nasal irritation—often mistaken for allergies.
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Difficulty concentrating, particularly among children and people working from home.
At AirGreen, we know these symptoms are typical of a poorly ventilated indoor environment, where concentrations of invisible pollutants become a serious concern. And this reality is even more pronounced in colder regions like the North Shore, where homes are often sealed tight to conserve heat.
Why is indoor air more polluted than outdoor air?
Contrary to popular belief, outdoor air—even in urban areas—is constantly refreshed. Indoors:
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Pollutants accumulate (cleaning products, wood stoves, varnishes, etc.).
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Air renewal is often non-existent or insufficient.
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Windows remain closed most of the year (due to the climate).
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The absence of a proper mechanical ventilation system (like a high-performance ERV) makes the problem worse.
Solutions provided by AirGreen: real-life cases from the North Shore
Here are a few concrete examples of interventions following the test results:
Boisbriand – Family of four, home built in 2008
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Identified problem: CO₂ levels > 1,500 ppm at night, window condensation, cooking odors.
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AirGreen solution: installation of a Venmar AVS N Series air exchanger, with independent ducting.
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Result: immediate reduction of odors, no more morning headaches, improved sleep quality.
Blainville – Homeowner working remotely
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Identified problem: chronic fatigue and sore throat, high VOC levels in the home office.
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AirGreen solution: replacement of an inefficient HRV with a Zephyr 200E ERV, equipped with HEPA filters.
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Result: 48% reduction in VOCs measured after 10 days, comfort fully restored.
Mascouche – Multigenerational home
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Identified problem: high basement humidity, undetectable mold growth.
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AirGreen solution: centralized ventilation with a Fantech HERO 250 ERV, automated humidity control.
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Result: complete elimination of excessive moisture, air feels drier and fresher.
The air exchanger: a key asset for health and energy efficiency
A properly sized air exchanger, professionally installed by HVAC experts like AirGreen, provides:
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Constant, controlled ventilation with no heat loss.
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Significant reduction of indoor pollutants.
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Improved comfort (temperature, humidity levels, odors).
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Energy savings, as fresh air is preheated.
Why choose AirGreen to improve your air quality?
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Deep local expertise in North Shore home environments.
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Fast diagnostics using professional-grade instruments.
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A wide range of systems adapted to Quebec’s climate.
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Turnkey service: HVAC installation, system calibration, full walkthrough, and assistance with Hydro-Québec’s LogisVert rebates.
Conclusion: Your indoor air deserves your full attention
Breathing healthy air at home isn’t a luxury. It’s an absolute necessity, especially in a climate like the North Shore’s. This study conducted by AirGreen shows that the signs of indoor pollution aren’t always visible, but their effects are very real. Investing in a high-performance air exchanger means protecting your health, enhancing your comfort, and reducing energy costs. Don’t let the air you breathe become your worst enemy.