A flat roof installation that combines performance, silence and reliability
At AirGreen , we adapt each HVAC installation to Montreal's architecture. In this Plateau-Mont-Royal plex, we installed a Fujitsu Airstage wall-mounted heat pump with a condenser installed on a flat roof . The goal: to guarantee four-season comfort, easy maintenance access, and maximum longevity despite exposure to the climate.
Why the Airstage range meets the needs of a Montreal plex
Fujitsu's Airstage family is renowned for its fine modulation, reliable components, and cold resistance. In a typical plex configuration:
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interior diffusion by one or more wall heads effectively covers living rooms;
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the rooftop condenser frees up the backyard, respects the co-ownership and reduces noise transmission;
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Inverter performance lowers consumption compared to electric baseboards.
Our installation method: clean, durable, compliant
Raised support and membrane protection
We place the outdoor unit on a galvanized trestle on wooden foundations resting on the gravel layer. Anti-vibration pads limit resonances. The support points are distributed to protect the roof's waterproofing membrane and facilitate water drainage.
Clearances and air circulation
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Respect the clearances at the front and rear for effective defrosting in winter.
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Orientation of the propeller away from obstacles (skylights, parapets) in order to avoid air recycling .
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Route of connections on the roof kept as short as possible to preserve seasonal efficiency.
Refrigeration connections and power supply
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Refrigeration lines exit under black insulated sheath to the parapet, then protected vertical descent.
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Total length of approximately 8 to 12 meters , calibrated as needed with additional load to stay within the Fujitsu performance window.
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Protected communication cable and dedicated power supply ; double-pole circuit breaker and disconnection means near the unit, in accordance with RBQ/CSA requirements.
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Defrost drain extended and directed to a drainage area, away from traffic.
Drilling, sealing and finishing
Inside, the wall heads are fixed at the optimal height (≈2.10–2.20 m). We make a clean drilling with a gravity slope for condensates, installation of a sheath and vapor barrier seal . The seals ensure the airtightness of the envelope and limit cold air bridges.
Vacuuming, testing and configuration
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Deep vacuum , stabilization and leak testing.
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Checking delta-T in heating/cooling, intensity, and balancing fan speeds.
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Adjust the sweep to avoid direct airflow onto occupants and optimize stratification.
Result: constant comfort and simplified maintenance access
Comfort and savings
The heat pump maintains a stable temperature with low noise. Inverter cycles reduce peak consumption and energy bills compared to all-electric heating.
Access and maintenance
The rooftop location provides safe technical access without disturbing occupants. We schedule annual HVAC maintenance : coil cleaning, leak testing, electrical inspection, refrigeration measurements, and adjustments.
Winter on a flat roof: our attentions
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Cleared free for defrosting ;
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Routing of water discharge outside passage areas;
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Seasonal checks of the fixing and routing of the connections after freezing/thawing episodes.
Sizing and interior deployment
Capacity and distribution
For a plex dwelling in the Plateau, the range of 9,000 to 18,000 BTU/h per person covers most rooms. We always validate the thermal load (orientation, glazing, sealing) to avoid over- or undersizing.
Air quality and humidity
In summer, aiming for 45–50% RH ensures comfort and material preservation. Dedicated drying modes prevent overcooling, especially in open areas.
Grants and administrative compliance
Depending on the chosen configuration and the approved performance, the solution may be eligible for active programs. We assist with the verification of criteria (including Energy Star and cold resistance) and the preparation of parts (detailed invoices, serial numbers, compliant photos). Our coverage extends to Montreal, Laval, Longueuil, the North Shore and the South Shore .
What sets AirGreen apart
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Precise advice, clean HVAC installation , complete documentation;
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Strict compliance with standards, roof protection and durable finishes;
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Responsive after-sales service on Fujitsu , Midea , Gree , Sharp , Zephyr and other brands in our offer.
Plateau-Mont-Royal Project Review
The client benefits from four-season comfort , a clear backyard, and a system designed to last. The Fujitsu Airstage condenser on a flat roof combines easy maintenance, performance, and acoustic discretion—a solution perfectly suited to typical Montreal buildings.