When a Simple Ventilation Check Prevents Thousands in Renovation Costs
Some HVAC ventilation service calls don’t require new equipment or major renovations. Sometimes, all it takes is an expert eye to spot a technical oversight that has gone unnoticed for years. That’s exactly what happened during a recent service call in Longueuil, where a poorly connected exhaust duct was threatening not only the home's comfort but also its structural integrity. Thanks to AirGreen’s prompt intervention, the issue was resolved before the damage became irreversible.
Context: A Renovated Single-Family Home With No Proper System Check
A family in the Saint-Hubert area of Longueuil had just completed a major interior renovation, including new wall insulation, updated finishes, and partial modernization of the HVAC system. A few weeks after the work was done, the homeowners noticed high humidity levels in the main bathroom and a musty smell in the hallway leading to the basement.
Suspecting a problem with the air exchanger, they contacted AirGreen for a full ventilation system inspection.
Diagnosis: An Extraction Duct Completely Disconnected
Within minutes of our inspection, one detail stood out: a rigid duct coming from the bathroom appeared to terminate into thin air in the ground floor attic. Upon checking the system layout, we confirmed the duct had never been reconnected to the air exchanger during the renovation.
Consequences:
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Humid air from the bathroom was being discharged directly into the structure, leading to invisible moisture build-up in the attic.
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Stale air wasn’t circulating properly, clogging the ventilation unit’s filters.
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Eventually, the client would have faced a partial demolition to repair structural damage caused by excess moisture.
AirGreen’s Intervention: Targeted Repair and Thermal Imaging Analysis
Our team immediately took action:
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Accessed the attic to locate the disconnection point.
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Cleaned the upstream ducts to remove moisture and early mold buildup.
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Securely reconnected the forgotten duct to the air exchanger’s intake.
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Replaced the clogged MERV 13 filters.
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Checked the entire duct network with a thermal camera to verify joint integrity.
Technical details of the existing unit:
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Brand: Lifebreath
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Model: RNC5-TPD
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Airflow: 150 CFM
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Filtration: MERV 13
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Efficiency: 70%
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Installation age: 6 years
Results: Comfort Restored, Humidity Under Control
One week after our visit, indoor air sensors confirmed the relative humidity had dropped to 47%, a perfectly healthy level. The musty odors vanished, and the client avoided what could have become a costly invasive renovation.
We also installed a temporary smart dehumidifier in the attic to ensure complete drying and enhanced long-term protection.
Why This Story Reflects Many Common Mistakes
This case is far from rare. In residential areas like Longueuil, Boucherville, or Saint-Lambert, it’s not uncommon for general contractors or DIYers to forget to properly reconnect ventilation ducts. These mistakes are often invisible but can lead to serious consequences:
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Structural damage to the building
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Hidden but harmful mold growth
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Reduced energy efficiency
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Ongoing thermal discomfort
Our tips to avoid these mistakes:
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Always request a full post-renovation inspection by a certified HVAC specialist.
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Schedule annual preventive maintenance for your ventilation system.
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Never block or modify ducts without a validated plan.
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Rely on certified mechanical ventilation technicians for all installations.
AirGreen: Real-World Interventions That Make a Real Difference
At AirGreen, our mission goes far beyond selling and installing equipment. Every day, we respond across Montréal, Longueuil, Laval, the South Shore, and the North Shore to ensure the efficiency, safety, and durability of HVAC systems for our residential and commercial clients.
Our certified technicians use advanced tools to:
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Locate invisible leaks or disconnections
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Analyze air quality and humidity levels
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Replace filters and rebalance airflow
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Extend the lifespan of your HVAC system
Conclusion: A Minor Oversight Can Be Costly… Unless AirGreen Catches It in Time
The story of this family in Longueuil is a reminder that a poorly checked HVAC installation can result in serious structural and financial damage. Thanks to our fast, precise, and professional intervention, we avoided a disaster and restored a safe, healthy environment.
Have you recently renovated your home? Not sure if your ventilation is working properly? Contact AirGreen for a complete inspection of your ducts.