Optimizing a building’s ventilation in Montréal or elsewhere on the South Shore, North Shore, in Laval or Longueuil is a major investment. Yet, many mistakes still occur far too often during HVAC ventilation system installation projects. At AirGreen, we’ve observed that these — often avoidable — mistakes can lead to significant additional costs, energy inefficiencies, or even health risks for occupants.
In this article, we share the 5 most costly mistakes our technicians regularly encounter in the field. Our goal: to offer you practical expertise drawn from our many interventions across Greater Montréal, to help you avoid these pitfalls and ensure your ventilation system functions flawlessly.
Inaccurate assessment of ventilation needs
An inadequate diagnosis from the start
One of the most frequent mistakes we see is the lack of a precise analysis of the building’s needs. Too often, a ventilation system is installed without considering:
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The total surface area,
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The building’s daily occupancy,
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The type of use (residential, commercial, industrial),
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The level of thermal insulation.
The result: a system that’s either oversized, causing energy overconsumption, or undersized, unable to provide adequate air renewal. At AirGreen, we systematically conduct a thermal load study and required airflow analysis to tailor our ventilation installations to each space’s reality, whether in Montréal or on the South Shore.
Installation without regard for local codes
Ignoring HVAC regulations
A serious error we regularly encounter is non-compliance with Québec’s Building Code and RBQ recommendations. This includes:
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Improperly sized exhaust ducts,
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Non-compliant air inlets,
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Airflows below the required minimums.
Such installations can lead to fines, mandatory rework, or in some cases, a failed municipal inspection. At AirGreen, our team continuously keeps up to date with the latest regulations to deliver certified, safe, and long-lasting ventilation installations.
Neglecting maintenance and future accessibility
Designing the installation with no thought for tomorrow
A too-often overlooked mistake is failure to plan for future maintenance. Some companies install ducts or air exchangers in inaccessible areas (attic, drop ceiling, etc.), making any maintenance operation complicated and costly.
Our technicians, on the other hand, design smart installations, focusing on:
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Accessibility of filters, ducts, and motors,
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Easily identifiable maintenance hatches,
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Modular systems allowing adjustments without demolition.
This significantly lowers maintenance costs and extends the system’s lifespan.
Using substandard materials
Immediate savings that cost more in the long run
Some less rigorous installers still use low-quality ventilation components: uninsulated flexible ducts, poorly sealed conduits, inefficient exchangers, or noisy fans. This not only reduces system efficiency but also increases:
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Ambient noise in rooms,
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Thermal losses,
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Dust and pollutant infiltration.
At AirGreen, we prioritize certified, durable materials, often Canadian-made, that meet CSA standards and ENERGY STAR® certifications. This approach guarantees a high-performing system for years to come.
Failing to balance the system
An unbalanced system = guaranteed discomfort
One of the most often overlooked technical elements is airflow balancing. A poorly balanced ventilation system creates:
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Over-ventilated areas (drafts, heat loss),
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Under-ventilated areas (humidity, stale air),
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Pressure differences between rooms.
Our technicians use precision anemometers and manometers to adjust each air supply and return. The result: optimal comfort and even air quality throughout the entire space.
Field testimonial: a successful correction in Ahuntsic
As an example, we were recently called in to revise a poorly designed installation in a family home in Ahuntsic, Montréal. The homeowner was dealing with window condensation and mold in certain rooms.
Upon inspection, we found:
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The HRV air exchanger was undersized,
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No duct balancing had been performed,
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The kitchen exhaust was non-compliant.
We completely reinstalled a Venmar EVO5 exchanger, properly sized for the living space, with R6 insulated ducts. We precisely balanced each outlet and installed accessible control dampers. Since then, the client has enjoyed increased comfort, cleaner air, and optimized energy performance.
What we guarantee at AirGreen
At AirGreen, we don’t just install ventilation systems. We support you every step of the way to ensure:
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Ventilation tailored to your actual needs, whether you’re in Longueuil, Laval, or the North Shore,
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Full code compliance, with no surprises,
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Reliable after-sales service, with easy maintenance access,
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High-quality materials, tested by our teams,
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Professional technical balancing, ensured by our specialized technicians.
We believe that every ventilation system should tangibly improve the occupants’ quality of life. And that starts with an uncompromising installation.
Conclusion: avoiding mistakes means choosing expertise
Investing in quality ventilation means protecting your health, your comfort, and your budget. By avoiding these five critical mistakes, you ensure a system that’s efficient, durable, and compliant. And for that, relying on HVAC experts like AirGreen is a wise choice.
Whether you’re in Montréal, Laval, Longueuil, on the South Shore or the North Shore, we’re here to offer you a custom, error-free ventilation installation.