A revealing experiment on the South Shore: when the absence of mechanical ventilation transforms daily life
At AirGreen, we recently assisted a family from the South Shore of Montréal with a highly unusual project: to test what it’s like to live without mechanical ventilation in their single-family home located in Saint-Lambert for one full month. The goal? To objectively assess the impact of not having a controlled mechanical ventilation system (CMV) on indoor comfort, air quality, and overall well-being. This out-of-the-ordinary experience now allows us to shed light on the real issues tied to proper residential ventilation, which is often underestimated—especially in a region as humid as the South Shore.
Context: a renovated home, but poorly ventilated
This family of four—two adults and two children—live in a home built in the 1980s, recently renovated with upgraded insulation and windows. However, as is often the case with tightly sealed homes, indoor air is not naturally renewed. Before our intervention, the home had no mechanical ventilation system, relying solely on opening windows manually—a method that quickly proved inefficient and inconvenient.
The consequences of lacking mechanical ventilation
Over 30 days, we supported the family throughout the experiment by providing measurement tools: CO₂ detectors, hygrometers, VOC sensors (volatile organic compounds), and fine particulate matter (PM2.5) analyzers. The findings were clear:
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CO₂ levels regularly exceeded 1,200 ppm in the bedrooms, affecting focus and sleep quality.
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High humidity levels, often surpassing 70% in the bathroom and basement, encouraged mold growth.
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Increased presence of VOCs and PM2.5, particularly after using cleaning products or while cooking.
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A stale atmosphere, frequent fatigue, morning headaches in the children, and eye irritation.
The limitations of simply opening windows
The family attempted to make up for the lack of mechanical ventilation by regularly opening windows. But this quickly showed its limits, especially:
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In winter, due to heat loss.
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On very humid or hot days, as outdoor air is not always cleaner.
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At night, for security and noise reasons.
AirGreen’s intervention: installing a mechanical ventilation system with heat recovery (HRV)
At the end of the month-long trial, we installed a Venmar EVO5 500 HRV mechanical ventilation system, a high-performance solution perfectly suited for residential homes on the South Shore. This model is designed for cold climates and allows for:
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Continuous renewal of indoor air, without heat loss.
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Extraction of excess humidity in damp rooms (bathroom, kitchen, basement).
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Enhanced air filtration, using MERV 8 filters that trap allergens and dust.
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Significant reduction of indoor pollutants.
The installation process
Our HVAC technicians handled:
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A detailed analysis of the home’s structure.
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The design of a balanced air distribution plan (fresh air intake and stale air extraction).
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The installation of a discreet duct system, optimized to minimize pressure losses.
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Commissioning of the system and a detailed walkthrough for the family on how it works and how to maintain it.
The entire job was completed in two full days, with minimal disruption for the occupants.
Immediate results after installation
Just one week in, the family reported:
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Fresher, lighter indoor air.
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The disappearance of morning headaches.
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A drop in humidity of over 20% in problematic areas.
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Better sleep quality, confirmed by CO₂ data.
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An overall increased sense of comfort, especially in the bedrooms.
Available grants: a smart investment
With our help, the family qualified for the LogisVert grant from Hydro-Québec, covering up to 30% of the cost of the ventilation system installation. We took care of the entire administrative process—from the initial application to securing the funds.
Why mechanical ventilation is essential, even in cold climates
On the South Shore, the climate is defined by:
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Cold, dry winters, when natural ventilation is often overlooked.
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Humid summers, where opening windows brings in outdoor pollutants (ozone, pollen, mold spores, etc.).
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The tight sealing of modern homes, which prevents natural air renewal.
Without mechanical ventilation, air quickly becomes stagnant, which can affect occupants’ health, damage the home’s materials (mold, condensation inside walls), and undermine the home’s overall energy efficiency.
Our real-world expertise: hundreds of successful installations
At AirGreen, we’ve installed hundreds of heat recovery mechanical ventilation systems throughout the South Shore, in cities such as Brossard, Longueuil, Châteauguay, and Saint-Bruno-de-Montarville. Every home, every building, and every project requires a customized assessment to ensure optimal performance.
Our installations rely on:
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Certified, well-known products, like Venmar, Lifebreath, Broan, and Aldes.
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Local expertise, fully aligned with Québec’s climate and regulatory standards.
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A human, educational approach, so each client fully understands and confidently uses their system.
The takeaway
Trying to live without mechanical ventilation in a modern home is not only uncomfortable—it can be downright harmful to your health. The experience of this South Shore family clearly shows: indoor air that isn’t renewed quickly becomes a major issue.
A quality heat recovery ventilation system is a long-term, cost-effective solution (especially with available grants) and is essential for maintaining a healthy, stable indoor environment, year-round.
Ready to improve your indoor air quality?
At AirGreen, we’re here to guide you, assess your needs, and install a custom HVAC mechanical ventilation system—whether you’re in Montréal, Laval, Longueuil, the North Shore, or the South Shore. Contact us for a free assessment and start breathing easier today.