A thoughtful flat roof HVAC upgrade designed for four-season comfort and easy maintenance access
Urban context and customer needs
In the Southwest (Griffintown) , the flat roofs of modern condominiums impose precise rules: unobstructed air circulation, vibration control, perfect sealing of penetrations and compliance with permissible loads. The client wanted a compact heating and cooling solution for his condo, quiet, efficient in mid-season and reliable during heat waves—without encroaching on the interior living space. We recommended a Zephyr wall-mounted heat pump with a roof-mounted condenser, a configuration that frees up the facades, facilitates maintenance and optimizes the length of refrigeration connections.
Equipment selection: Zephyr wall-mounted, sized for the condo
For an average-sized apartment in Griffintown, the insulated envelope and solar exposure guide the capacity choice (generally 9,000 to 18,000 BTU/h for a single indoor unit). The Zephyr range meets the client's criteria: summer cooling efficiency, low-temperature supplemental heating, quiet operation, and compatibility with a flat-roof HVAC system . We always size based on actual thermal loads (orientation, glazing, infiltration) to avoid oversizing—a source of short cycles, noise, and efficiency losses.
Roof installation details: stability, clearances, silence
The Zephyr condenser is placed on an aluminum support anchored to treated logs resting on the roof gravel. This configuration:
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distributes the load and preserves the membrane;
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creates sufficient elevation for snow and runoff;
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limits vibration transmission thanks to anti-vibration pads and controlled tightening.
We ensure the required clearances around the battery and propeller to maximize heat exchange and reduce hot air recirculation. Maintenance access is from the front, without disturbing surrounding equipment (technical chimney, vents, or neighboring units).
Refrigeration and electricity path: short, clean and watertight
From the roof, the refrigeration lines (closed-cell insulated copper) and the 240 V power supply run to the interior head through a sealed metal technical box . The opening receives a sleeve , a vapor barrier and a flashing compatible with EPDM/bitumen membrane. Result: no infiltration, no condensation. The total length remains short (approximately 3 to 6 m ), guaranteeing excellent seasonal efficiency and a less stressed compressor.
Condensate management: priority to gravity
Inside, we favor gravity flow of condensate to a drainage point. If the slope is insufficient, we integrate a silent lifting pump with a non-return valve and safety tank. On the roof, the outdoor unit is obviously outside the water accumulation zone and protected against gravel projections.
Construction site challenges and solutions implemented
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Roof access : technical window and guardrail present, we plan handling during quiet hours to respect the co-ownership.
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Vibrations and noise : combination of support + pads + torque tightening limits transmission to the structure; the distance from the guardrails avoids resonances.
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Waterproofing : all holes receive a multi-layer treatment (compatible sealant, flashing, butyl tape) and a maintenance sheet is given to the customer for annual monitoring.
Key installation steps (operational summary)
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Structural validation of the support area and flat roof layout plan.
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Installation of the support (aluminum) on stabilized beams , seat check, leveling.
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Installation of the Zephyr condenser and connection of the technical box.
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Refrigeration line pulling , nitrogen brazing, high pressure nitrogen leak testing .
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High vacuum (500 microns and stabilization), opening of the valves.
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Electrical connection with external disconnect switch and dedicated circuit breaker according to the current code.
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Installation of the interior head : root, template, drilling, fixing, plumb check.
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Condensate management (gravity preferred), water tests.
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Commissioning : checking currents, subcooling/superheating, supply/return temperatures.
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Customer Discount : User training, filters, HVAC maintenance and recommended schedule.
Measurable results for the condo
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Consistent comfort in summer thanks to laminar ventilation and precise shutter control.
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Lower consumption compared to a portable or window air conditioner.
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Low noise level , both inside and on the roof, suitable for co-ownership.
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Simplified maintenance : direct access to the condenser, natural de-icing facilitated by clearances.
HVAC Maintenance: The Routine That Extends Lifespan
To maintain performance:
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Clean the inner head filters every 1 to 2 months during use.
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Annual inspection : exchanger, fans, electrical tightening, refrigeration load, condition of insulation and roof fixings.
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Weeding/debris collection on roof and clearance control.
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Check drain and odor traps to prevent overflows.
We offer HVAC maintenance plans tailored to condominiums to streamline operations and limit travel.
Grants, compliance and best practices
Energy Star -qualified wall-mounted heat pumps designed for cold climates are eligible for assistance programs in Quebec (subject to performance and installation conditions). We support our customers in:
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eligibility verification ,
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documentation (detailed invoices, serial numbers),
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the installation photo file (clearances, supports, connections).
In terms of compliance, our work complies with manufacturers' specifications, local electrical requirements, and co-ownership rules (times, noise, facade aesthetics). On flat roofs, we add snow guards and additional elevations as needed to ensure protection above the snowpack.
Why this flat roof configuration in Griffintown?
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Urban aesthetics preserved : no projections on the main facade.
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Performance : short refrigeration path, therefore increased efficiency .
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Quick maintenance : access without disturbing the home.
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Durability : aluminum support and controlled anchoring limit corrosion and movement.
What we bring to AirGreen
Our team is proficient in HVAC installations in dense urban settings (Montreal, Laval , Longueuil , North Shore , South Shore ). We deliver:
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correct sizing (BTUs adapted to the housing),
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careful installation (nitrogen brazing, high vacuum, controlled tightening),
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complete documentation (maintenance sheets, usage advice),
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local, fast and proactive after-sales service .
For a condo in Griffintown, the Zephyr wall-mounted rooftop heat pump meets exactly what you need: discretion, efficiency, and easy maintenance. It's a tangible improvement in daily comfort, ready for hot summers and cool shoulder seasons—with an HVAC system designed to last.