Poor ventilation can turn a renovation project into a nightmare. That’s exactly what happened to a couple who owned a century-old duplex in the Villeray neighbourhood of Montréal. When they began major renovations in their basement to create a rental apartment, they hadn’t anticipated the consequences of a poorly designed HVAC ventilation system. Thankfully, our team at AirGreen stepped in just in time to fix the issue before the damage became irreversible.
Persistent Humidity and the Threat of Mold
Just a few weeks after completing the renovations, the homeowners noticed alarming signs: excessive condensation on the windows, a lingering musty smell, and suspicious stains appearing on the walls. Their newly finished rental unit, which was supposed to generate income, was quickly becoming uninhabitable.
Upon inspection, the diagnosis was clear: the ventilation system was inadequate, especially in high-moisture areas like the basement kitchen and bathroom. The extraction system was undersized, and there was no provision for fresh air intake.
Our Diagnosis: A Non-Compliant Ventilation System
When we were called in for a residential ventilation evaluation in Montréal, we immediately identified several critical issues:
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No heat recovery ventilator (HRV) was installed to ensure balanced air circulation.
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There was no dedicated extraction vent in the bathroom, causing humid air to stagnate.
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Poor duct layout, leading to dead zones and ineffective air renewal.
These mistakes could have jeopardized not just the comfort, but also the health of future tenants and the long-term structural integrity of the home.
Our Custom Solution: Centralized Ventilation with HRV
To resolve the problem, we designed a mechanical ventilation system tailored precisely to the layout of the duplex. Our work included:
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Installing a Venmar EVO5 500 HRV (heat recovery ventilator) with the right capacity for the total square footage.
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Running insulated rigid aluminum ducts to every key area (bedrooms, living room, kitchen, bathroom).
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Adding discreet yet effective extraction grilles to remove humidity and indoor pollutants.
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Integrating a wall-mounted smart control panel to allow airflow adjustments based on occupancy and seasonal needs.
The Result: A Healthy, Comfortable, and Code-Compliant Space
After our intervention, the improvement was immediate. The homeowners reported:
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Significantly improved air quality, with no odours or condensation.
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Lower indoor humidity, kept under 50%, even during the winter months.
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A positive review from an independent inspector, confirming the installation met the Québec Building Code.
Why Choose AirGreen for Your Ventilation Needs in Montréal, Laval, Longueuil, and the North/South Shores?
At AirGreen, we know that every renovation or construction project comes with its own challenges. That’s why we offer a personalized HVAC ventilation approach, focused on performance, durability, and full compliance with today’s standards.
Our Advantages:
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Expertise in residential and commercial ventilation, with over 15 years of hands-on experience.
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In-depth knowledge of architectural specificities across Montréal, Laval, and Longueuil.
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Coordination with general contractors to integrate our systems during the planning phase.
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Post-installation follow-up, including maintenance, cleaning, and seasonal adjustments.
Mistakes to Avoid in Any Ventilation Project
This story clearly shows how crucial it is not to overlook ventilation during renovations. Here are some practical tips to steer clear of common pitfalls:
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Never let an electrician or general contractor handle the ventilation without consulting an HVAC specialist.
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Be wary of cheap “all-in-one” systems that don’t truly meet your space’s needs.
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Always include ventilation in your initial planning — don’t make it an afterthought.
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Request a detailed airflow analysis before installation to ensure every room is properly ventilated.
More Real-World Examples of Our Successful Projects
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In Laval, we overhauled the ventilation system in a triplex where kitchen heat and odours were spreading uncontrollably due to poor extraction.
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On the South Shore, in Boucherville, our team installed a high-efficiency HRV in a passive house, ensuring optimal airflow while maintaining the building’s energy efficiency.
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In a rental building in Longueuil, we implemented a centralized ventilation system with HEPA filters to improve air quality in shared hallways.
A Final Word on Ventilation: Invisible, but Essential
Ventilation is often the forgotten piece in renovation or construction projects. Yet it’s at the core of comfort, health, and long-term building durability. Don’t let poor planning compromise your investment.
Call on our team of professionals for a complete diagnosis, custom solutions, and flawless execution.
At AirGreen, we don’t just move air – we create healthy, durable, and intelligently ventilated environments.