When Ductwork Turns into a Nightmare: A Critical HVAC Intervention in Montréal
In the vast world of residential and commercial HVAC in Montréal, some situations go beyond comprehension. Recently, at AirGreen, we were called in to inspect a central system that, according to the client, "never really worked since it was installed." What we discovered in this single-family home in the Ahuntsic–Cartierville neighborhood turned out to be the worst ductwork installation we’ve ever seen in the Greater Montréal area.
This job has become emblematic of our expertise—not just in repairs, but in thorough analysis, clear communication with the client, and the complete transformation of a faulty system into a high-performing, sealed, and code-compliant ductwork network.
An Initial Inspection That Said It All: Obvious Signs of a Poor Design
From the moment we arrived, the first signs were worrying. The client reported:
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Very cold zones upstairs despite the thermostat set at 24 °C
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Visible air leaks in the basement
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Loud whistling sounds from the ducts
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Extremely high energy bills
After inspecting the system with a thermal camera and airflow meter, we found air losses exceeding 40% throughout the network. The ducts were poorly insulated, oversized in some areas, completely crushed in others, with several joints taped together using hardware store duct tape.
The most alarming part? A section of the return duct was completely blocked by a piece of plywood that had been left inside… probably since the original installation, less than five years ago.
A System Flawed at Every Level
Here are some of the major technical errors we identified:
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Improperly positioned plenums, causing turbulence and poor air distribution
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Use of low-quality flexible ducting, poorly secured to the joists
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No return vent upstairs — compromising pressure balance
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Duct joints sealed with tape instead of professional-grade mastic
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Complete absence of load calculations or airflow assessments at the time of installation
These issues aren’t just serious—they directly impact comfort, air quality, equipment longevity, and energy consumption.
Our Methodical Approach: Tear Down, Recalculate, Reinstall
At AirGreen, we follow a rigorous methodology based on technical analysis and compliance with Canadian HVAC standards.
Step 1: Full Diagnostic
We produced a detailed technical report with photos, airflow readings, thermal measurements, and a comparison between the theoretical system requirements and the existing installation.
Step 2: Custom Redesign
Using simulation software, we modeled a brand-new rigid ductwork system, taking into account:
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The exact dimensions of each room
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Required insulation to prevent thermal losses
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The static pressure of the central unit (an existing Goodman 3-ton 36,000 BTU)
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The maximum duct length allowable to ensure proper airflow
Step 3: Full Reinstallation
We completely removed the old ductwork. Our team installed a rigid galvanized steel network, insulated to R-8 standards, sealed with mastic at every joint, secured with metal brackets, and included balanced return vents on each floor. The entire system was tested at the end to ensure air losses were below 5%.
The Result: Efficiency, Comfort, and Performance
After the work was done, the results were immediate:
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Even temperature in every room
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Quiet operation with no vibrations
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Electric bill reduced by 28% in the first month alone
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Perfect balance between floors
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Improved air quality (less dust and no stagnant humidity)
The client, stunned by the difference, agreed to share this story to raise awareness among other homeowners about the importance of proper HVAC installation from day one.
What You Should Know to Avoid an HVAC Nightmare
Never Underestimate Ductwork Design
Many homeowners invest in a high-performance heat pump or central furnace (Fujitsu, Bosch, Goodman, Lennox…) without realizing that system efficiency depends heavily on air distribution. Even the best unit in the world can’t compensate for a poorly designed duct system.
Work with a Certified Specialist
At AirGreen, we specialize in installing, repairing, and completely redesigning HVAC systems in Montréal, Laval, Longueuil, the North Shore, and the South Shore. Our technicians are trained to:
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Perform thermal load calculations (CSA F280)
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Analyze static pressure
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Ensure ductwork is sealed
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Comply with the strictest codes in the Québec Building Code
Watch for Signs of Bad Installation
Here are a few warning signs to keep in mind:
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Rooms that are always too hot or too cold
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Noisy or jerky system operation
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Mold or condensation inside ducts
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No return grille on the upper floor
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Crushed or visibly poor-quality flexible ducts
Why AirGreen Is Your Long-Term HVAC Partner
By choosing AirGreen, you’re choosing:
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A well-established local company in Montréal, attentive to your needs
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Fast, effective, and guaranteed service
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Total transparency on all work performed
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Custom solutions tailored to your home or commercial building
We firmly believe that comfort begins with a well-designed installation. An HVAC system isn’t just a machine—it’s an ecosystem. And at AirGreen, we make sure every part of that ecosystem works in harmony.
Conclusion: A High-Performing HVAC System Starts with Well-Designed Ductwork
This experience in Montréal is a powerful reminder: ductwork design is crucial to the overall performance of any heating and cooling system. Thanks to our expertise, we turned an energy disaster into an example of comfort and efficiency.
If you suspect issues with air distribution, or want to have your ductwork network inspected, reach out to our team. We respond quickly throughout Greater Montréal, with precision, know-how, and a true passion for the trade.