A typical Montreal construction site: Zephyr wall-mounted heat pump installed on a flat roof, quiet, efficient and designed for winter
In Rosemont–La Petite-Patrie, a plex owner wanted to stabilize the comfort of his home in both summer and winter while reducing his energy costs. The building has a flat roof, typical of Montreal , with a metal parapet and gravel. The goal: to install a compact wall-mounted heat pump , reliable in cold weather, with a discreet connection route and simple maintenance. At AirGreen , we recommend a Zephyr outdoor unit combined with a high-efficiency wall-mounted indoor head to provide heating and cooling in the living areas without major ductwork.
Why choose Zephyr for Rosemont?
Zephyr offers outdoor units well-suited to flat roofs in Greater Montreal: robust casing, quiet operation, stable performance at low temperatures, and compatibility with refrigeration lines of sufficient length to serve a dwelling located under the roof. For this project, we selected a capacity sized based on actual winter heat losses (insulation, infiltration, glazed surface, orientation). The load calculation prevents oversizing—a source of short cycles, noise, and unnecessary consumption—and guarantees excellent comfort in mid-season.
Special features of flat roof installation
The roof receives point loads and is subject to wind. We install the Zephyr unit on a raised, galvanized roof support , anchored to composite footings resting on treated wood distribution joists. This installation prevents any membrane perforation, respects the drainage slope, and limits vibration transmission to the structure. The raised roof ensures:
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A guard against snow accumulation,
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Free flow of defrost water,
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Better air flow around the exchanger.
We direct the discharge away from traffic areas and neighboring windows to reduce perceived noise and prevent the recirculation of cold air in heating mode. At the client's request, we position the unit toward the backyard, further from the street, to preserve neighborhood peace.
Refrigeration connection route and aesthetics
The insulated copper connections and the communication cable run along the edge of the parapet. The refrigerant connections are continuously insulated with a UV-resistant sheath; sensitive points are capped and sealed to prevent water infiltration. The white exterior capping option, visible from the roof but invisible from the street, ensures a clean finish and facilitates future work. The total length—from the indoor head to the condenser—meets the manufacturer's limits (pressure drop, oil/refrigerant top-up if required). We maintain compliant bend radii to preserve the integrity of the copper and compressor performance.
Electrical management and safety
Dedicated power comes from the dwelling panel, protected by a circuit breaker calibrated to the Zephyr unit's current rating. On the roof, a waterproof disconnect box (fuse/knife switch) is installed within the technician's reach, in accordance with the Quebec electrical code. The exterior wiring runs in a UV-resistant rigid conduit, securely fastened to the support; penetrations are sealed and counter-flashed to maintain the enclosure's watertightness. Grounding is verified and tested.
Resistance to the Montreal climate
The flat roof imposes snow and ice constraints. We plan:
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Rear and side clearance exceeds minimum recommendations to ensure airflow even in snow banks.
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Anti-vibration pads under the side members to limit structural transmission and protect the membrane.
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A defrosting plan : checking the automatic defrosting mode, free water drainage, absence of stalactites towards the gutter.
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Optionally, a tray heating cable and snow guards if the building has loaded cornices in winter.
Expected comfort and performance
In air conditioning mode, the wall-mounted fan ensures uniform horizontal airflow , ideal for open spaces. In heating mode, the inverter modulates finely; the heat pump reduces electricity consumption compared to baseboards and maintains a stable temperature without "hot flashes." Our settings include:
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Calibration of air flow according to the room and ceiling height,
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Optimization of shutters to avoid thermal shadow areas,
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Activation of economy functions (standby, night eco setting).
Noise and neighborhood: good practices
On rooftops, noise travels differently. We choose a blast axis opposite neighboring windows, add anti-vibration spacers, and check, at full power, for resonance with the parapet. The measured result remains below the usual municipal thresholds, while ensuring nighttime comfort for both the client and neighbors.
Simplified HVAC Maintenance
To preserve seasonal yield:
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Cleaning the wall head filters every 4 to 8 weeks during periods of intensive use,
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Annual inspection by AirGreen: refrigerant pressure, electrical tightening, condition of fins , sensors, defrosting, drainage and tightening of the support,
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Permanent clearance of the roof around the unit (leaves, snow).
Regular maintenance maintains COP in winter and SEER in summer, extends service life and reduces the risk of breakdowns during peak periods.
Deadlines and organization of the worksite
Our team plans the intervention with secure roof access. Key steps:
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Validation of routes and protection of surfaces (carpets, corners, stairwells).
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Controlled drilling and fire-resistant sealing if connections cross a separation.
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Setting up the support, installing the unit, pulling the connections and the power supply.
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Vacuum and deep vacuum , pressure gauge leak test, refrigerant release.
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Assisted starting, overheating/subcooling control, modulation check.
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Provision of usage and maintenance advice.
In a Rosemont complex, the standard intervention takes one day when access is coordinated.
Grants and Eligibility
For high-efficiency wall-mounted heat pumps , Quebec programs may require Energy Star certification and verified cold weather performance (down to -25°C or -30°C, depending on the case). When the Zephyr indoor/outdoor unit combination meets the criteria, we prepare the file (detailed invoices, certificate numbers, photos, proof of installation). We systematically confirm the exact eligibility of the selected configuration before filing.
Tips for flat roof owners in Montreal, Laval and Longueuil
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Support height : Allow at least 30–45 cm of clearance under the base for snow; more if the roof drains slowly.
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Orientation : avoid blowing against a wall less than 30 cm away; aim for an area open to the prevailing wind without recirculation.
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Drainage : Direct defrost runoff away from the main drain outlet to prevent icicles.
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Wiring : accessible and waterproof disconnection; sealed and membrane-compatible roof passage.
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Aesthetics : favor harmonized capping ; on the facade, align the hoods vertically for a clean finish.
Result for our client in Rosemont–La Petite-Patrie
The property benefits from consistent fresh air circulation in the summer and stable heating in the winter. The noise level on the terrace is discreet; from the street, the unit is barely noticeable. The owner follows an annual maintenance plan with AirGreen, ensuring the performance and longevity of the investment.
Why entrust your HVAC installation to AirGreen?
We master the constraints of Montreal flat roofs : membranes, loads, wind, snow, access. Our certified installers work with a quality protocol: load calculation, nitrogen pressurization, vacuum < 500 microns, modulation control, waterproof and clean finishes. We operate in Montreal , Laval , Longueuil , on the North Shore and the South Shore , with realistic deadlines and responsive after-sales service. Our installation reports, supported by photos, facilitate grant applications and future maintenance.
Quick Facts (Project Summary)
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Equipment type: Zephyr wall-mounted heat pump (outdoor unit on flat roof).
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Installation: galvanized support on soles, treated wooden side members, anti-vibration pads.
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Route: insulated refrigerant connections up to the inner head; clean outer capping ; sealed electrical disconnection within reach.
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Key points: wind clearances, defrost management, no membrane perforation, controlled noise.
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Areas served: main living areas; possible extension to multi-zone depending on building configuration.
What's next?
Do you have a plex in Rosemont, Plateau , Villeray , Laval , or on the South Shore and are hesitating between a wall-mounted air conditioner and a heat pump ? At AirGreen, we evaluate the load, roof feasibility, route aesthetics, and noise impact before recommending the best solution. Contact us for a technical visit and a clear quote, including, if applicable, an estimate of financial assistance.