A poorly planned project, costly mistakes, and AirGreen’s corrective intervention
In many neighbourhoods across Montréal, Laval, Longueuil, the North Shore, and the South Shore, more and more homeowners attempt to install ventilation systems themselves in an effort to cut costs. Unfortunately, as shown by the case of the Dubois family in Rosemont, these DIY projects can quickly turn into a technical and financial nightmare. At AirGreen, we were called in urgently to correct a poorly executed ventilation installation that not only cost the family a significant amount of money but also posed a health risk.
The Context: Trying to Save Money… and Paying the Price
The Dubois family had recently renovated their single-family home and wanted to install a central ventilation system to improve indoor air quality, especially with two young children in the house. For budgetary reasons, they decided to skip professional help and do the installation themselves, relying on video tutorials and DIY forums.
Their original goal: to install a small heat recovery ventilator (HRV) purchased online from an unknown brand, using a pre-fabricated duct kit.
Critical Installation Mistakes
From our very first visit, our technicians quickly identified several major errors that explained why indoor air quality had actually worsened after the installation:
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Incorrect HRV sizing: the airflow was insufficient for the total square footage of the home.
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Poorly sealed ducts causing significant air loss and cross-contamination between rooms.
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Improper location of the main unit, installed near a heat source, which interfered with the system’s function.
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No fresh air intake from outside, resulting in constant recirculation of stale air.
In addition to these technical issues, there were no high-efficiency filters in place, exposing the family to fine particles and allergens.
Health and Comfort Consequences
In just two months of using the DIY system, the negative effects were already evident:
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Increased humidity in certain rooms, especially the basement.
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Persistent odours in bedrooms and the kitchen.
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Appearance of mould on interior walls.
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Frequent respiratory symptoms in the children (coughing, congestion, fatigue).
That’s when the family decided to call AirGreen to assess the situation.
AirGreen’s Intervention: Diagnosis, Dismantling, and Full Reinstallation
Our team began with a comprehensive ventilation diagnosis, including duct inspections with a camera, airflow tests, indoor air quality analysis, and a full audit of the installed components.
Findings: the DIY installation wasn’t just ineffective—it posed a real health risk to the home’s occupants.
We proposed a complete solution:
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Removal of the existing system.
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Installation of a high-efficiency Zephyr ZP700 HRV with HEPA filters.
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Custom duct network designed with strategically placed air outlets.
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Integration of smart humidity sensors for automated ventilation control.
Technical Details of the New Installation
AirGreen’s solution included:
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Brand and model: Zephyr ZP700
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Capacity: 130 CFM airflow, ideal for a 2,200 sq. ft. home
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Filtration: HEPA filters + washable pre-filters
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Energy efficiency: heat recovery up to 92%
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Smart controls: wall-mounted thermostat with CO2, humidity sensors, and programmable scheduling
Additionally, this installation was eligible for the LogisVert grant, allowing the family to recoup nearly $1,100 in total project costs.
Results: Comfort Restored, Air Purified, Lesson Learned
One week after the intervention, the changes were obvious:
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Odours disappeared and humidity dropped significantly.
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Measured indoor air quality improved by a factor of four.
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Noticeable improvement in the children’s respiratory health.
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Quiet and easy-to-use system with minimal maintenance.
The Dubois family admitted they had underestimated the complexity of a professional HVAC installation and now want to share their story to prevent others from making the same mistake.
Key Lesson: Why You Should Avoid DIY Ventilation Installations
Here are the main risks of doing a ventilation installation without professional help:
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Incorrect sizing: can compromise the system’s performance.
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Improper duct design: leads to leaks, condensation, and noise.
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Low-quality materials: not durable, often non-compliant with Québec building codes.
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Ineligibility for grants: poor installations often disqualify the project from financial assistance.
By comparison, choosing AirGreen guarantees:
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A certified installation that complies with CSA and RBQ standards.
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Proven equipment designed for Québec’s climate.
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Full after-sales support, including HVAC maintenance and warranty coverage.
Client Testimonial: “We Thought We Were Saving Money, But It Cost Us More”
“We tried to do it ourselves to save money… and in the end, it cost us almost twice as much. Thankfully, we found AirGreen. The team was fast, professional, and most importantly—honest. Today, we breathe better and sleep with peace of mind.”
Trust Real Professionals for Your Ventilation Needs
Whether you’re renovating, building new, or need to fix an existing system, AirGreen is your trusted partner for all residential and commercial ventilation work in Montréal, Laval, Longueuil, the North Shore, and the South Shore.
Don’t put your health or your budget at risk: trust your ventilation to real experts.