A poorly designed or poorly maintained system can do more harm than good
Ventilation in a condominium in Montréal is not just a technical detail: it directly affects the health of occupants, thermal comfort, indoor air quality, and the building’s durability. As experts in HVAC installation and maintenance, at AirGreen, we are frequently called in to fix mistakes made by other contractors, often at the expense of the co-owners. Here's a detailed guide to help you avoid the most frequent mistakes in ventilation systems for condos on the Island of Montréal, in Laval, Longueuil, as well as on the North Shore and South Shore.
Why Ventilation Is Crucial in Condominiums
Unlike single-family homes, multi-unit buildings have very specific needs. Several units share ducts, common areas, and sometimes a centralized air handling system. This means that even one design or maintenance error can affect the entire building.
Poor ventilation can lead to:
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Excessive condensation in ducts and walls
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Recurring mold issues
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Poor indoor air quality (CO2, VOCs, humidity)
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Increased energy consumption
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Ongoing complaints from co-owners or tenants
Mistake #1: Underestimating the Importance of Mechanical Ventilation
Many real estate developers still opt for minimalist solutions (such as simple exhaust fans in bathrooms or kitchens), while the Québec Building Code recommends mechanically controlled ventilation systems (HRVs or ERVs). This often results in stagnant air and a lack of proper air exchange.
Our recommendation: Every new condo development or major renovation project should include an HRV (Heat Recovery Ventilator) or ERV (Energy Recovery Ventilator) to ensure constant fresh air supply while minimizing heat loss.
Mistake #2: Failing to Adapt the System to Montréal’s Climate
In Montréal and the surrounding areas, winters are long and harsh. Installing a ventilation system designed for milder climates is a frequent mistake.
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Real-life example: During a service call in Rosemont, we discovered an air exchanger installed without any consideration for winter freezing, which caused the motor to seize and the entire system to shut down. Our technicians replaced the unit with a model equipped with integrated antifreeze protection, suited to our winters.
Mistake #3: Neglecting Regular System Maintenance
Even a well-installed ventilation system quickly loses efficiency without regular HVAC maintenance. Clogged filters, dirty ducts, and unbalanced fans all degrade air quality.
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Absolutely to avoid: Delaying maintenance or ignoring system alerts, especially in high-density buildings.
What we offer at AirGreen: We provide customized maintenance plans for condo boards, including complete cleanings, performance diagnostics, and on-site adjustments.
Mistake #4: Sharing One System Between Units Without Proper Zoning
A central system that serves multiple units absolutely must include zoning systems and independent controls. Otherwise, some units receive too much air while others don’t get enough.
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Example from Laval: A new condo building with a single system for six units had no motorized dampers. The result: complaints about noise, drafts, and overheating. We installed a digital zoning system with individual wall controls, restoring consistent comfort.
Mistake #5: Overlooking Ventilation in Common Areas
Stairwells, hallways, and underground garages are often the last to receive proper ventilation. Yet these are high-risk zones for contamination (exhaust fumes, mold, smoke).
Our recommendations:
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Install CO detectors and automatic fans in garages
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Include fresh air intake grilles in stairwells
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Clean common area ducts every 2 to 3 years
Mistake #6: Choosing the Wrong Equipment or Components
We still encounter undersized equipment, poorly insulated ductwork, or systems installed without proper ventilation schematics. This increases pressure losses, noise, and drastically reduces system lifespan.
Examples of inadequate equipment:
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Loud axial fans instead of centrifugal models
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Uninsulated flexible aluminum ducts in drop ceilings
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Air grilles that are too small for required airflow
What we do at AirGreen: We only use certified components, designed for multi-unit residential buildings, and we create custom technical plans before each installation.
Our Recent Interventions in Condos
At AirGreen, we’ve completed numerous installations and corrections of ventilation systems in condominiums across Montréal, Longueuil, Laval, the North Shore, and the South Shore:
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In Verdun: Full replacement of a central HRV system with an energy-efficient model featuring an aluminum heat exchanger
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In Boisbriand: Installation of rigid ducts in a 4-story building, with reinforced soundproofing
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In Boucherville: Integration of a CO detection system in underground garages, with centralized alert to the concierge’s control panel
Practical Tips for Condo Boards and Property Managers
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Request a comprehensive diagnostic before any new installation or system modification
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Ask for an annual maintenance plan with an intervention history
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Verify compliance with RBQ standards and local municipal regulations
Why Choose AirGreen for Your Condo HVAC Projects?
We understand the unique realities of condominiums: shared budgets, structural constraints, acoustic requirements, strict standards. Our team offers:
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Proven technical expertise in multi-family residential HVAC
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Customized solutions based on the building’s layout
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Complete transparency at every step of the project
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Support for applying to LogisVert or Novoclimat grants, if eligible