A successfully completed project on a flat roof, in the heart of the Plateau-Mont-Royal, where we transformed an underutilized technical space into a discreet engine of four-season comfort. At AirGreen , we combine load studies, HVAC installation know-how and durable finishes to offer a reliable, quiet heat pump that's ready for Montreal's winter.
A flat roof construction site designed for longevity and silence
The building is a typical Plateau plex, with rooftop access and unobstructed views. Our client wanted a compact system that would be efficient in summer, spring, and fall, without compromising the aesthetics of the interior courtyard. The solution: a Zephyr wall-mounted heat pump (capacity sized between 12,000 and 18,000 BTUs depending on the calculated load) with an outdoor unit installed on the roof. This configuration frees up the facades, reduces noise transmission to the living areas, and simplifies regulatory clearances.
Structuring points of the site
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Gravelled flat roof with parapet: ideal for mounting on a raised support to ensure drainage and snow removal.
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Existing technical path in the immediate vicinity: perfect for watertight penetration of refrigeration connections and the electrical supply.
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Secure service access : allows for quick maintenance for HVAC servicing without disturbing neighbors.
Equipment selection and sizing
We size each system based on a load calculation (envelope, orientation, infiltration, floors, glazing). The profile of the housing and the surface area served lead us to a Zephyr wall-mounted heat pump from the residential range, known for its ease of maintenance, stable performance and compatibility with the cold winters of Greater Montreal .
Why a mural on this project?
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Modularity : one indoor head is sufficient for the main zone; the multi-zone option remains possible later.
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Seasonal efficiency : excellent for air conditioning (“ wall-mounted air conditioner ” in summer) and very good in mid-season for heating.
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Reduced footprint : discreet indoor mounting, condenser away from living spaces.
Grants: Several wall-mounted heat pumps are eligible for current programs when they meet Energy Star and cold weather performance criteria. We always validate eligibility on a case-by-case basis for Montreal , Laval , Longueuil , North Shore and South Shore , and we provide support for the process.
Installation Details — What Makes the AirGreen Difference
Support and anti-vibrations
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Raised galvanized frame mounted on continuous skids/bases, with treated wood crosspieces and anti-vibration pads under the support points. The raised height (~45 cm) keeps the unit above snow accumulation and preserves free air circulation.
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Clearances respected on all sides: maintenance and defrosting remain optimal, static pressure on the fan side remains low, for stable performance and a contained noise level.
Refrigeration path and sealing
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Short refrigerant connections (≈ 3 to 5 m) between the outdoor unit and the indoor head: less pressure loss, better responsiveness, and often no additional refrigerant charge required compared to the factory charge.
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Penetration through existing metal cap : collar, vapor barrier and polyurethane sealant ensure water and air tightness. UV-resistant insulation is continuous up to the interior head to prevent thermal bridges and condensation.
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Tube curvature radius respected: reliability of brazing and stability of capillaries/solenoid valves.
Electricity and protections
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Chassis-mounted disconnect box within reach of the technician, compliant with the Code. Dedicated feed from the main panel (double-pole breaker as per the nameplate), mechanical conduit to the roof, waterproof cable glands on all entries.
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Grounding checked, torque tightened and insulation tested.
Quality controls
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High pressure nitrogen test with foam solution on all joints.
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Deep vacuum (< 500 microns) with lift control; guarantees a dry and clean circuit.
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Supervised start-up : checking compressor/fan intensity, overheating/subcooling, blowing temperature, and calibration of comfort parameters (shutters, speeds).
Condensate management
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In summer , drainage is by gravity from the interior head (guaranteed slope, anti-odor siphon and protected outlet).
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In winter , the management of defrosted frost on the roof is provided for by the positioning and clearances of the support; no projection onto pedestrian surfaces.
Aesthetics, acoustics and neighborhood
The rooftop installation preserves the Plateau's historic facades. The anti-vibration pads and the rigidity of the frame limit the transmission of low frequencies. Defrost cycles remain imperceptible indoors, and the direction of the airflow keeps any disturbance away from neighboring windows and terraces.
Result for the customer
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Immediate comfort in the living room thanks to soft and even diffusion.
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Lower operating costs in the off-season in heating mode and maintenance of stable coolness in summer.
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Simplified HVAC maintenance : accessible washable filter, easy roof access for the outdoor unit, quick annual preventive inspection.
Practical advice and mistakes to avoid
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Don't underestimate the load : an overly optimistic 9,000 BTU will run at full speed and wear out prematurely. We size with a reasonable comfort margin.
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Avoid excessive line runs : beyond certain lengths, efficiency drops and an additional charge becomes necessary. Here, the proximity of the technical cap guarantees an efficient route.
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Protect insulation from UV rays and birds: continuous sheaths and mechanical fasteners prevent tearing.
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Respect snow clearances : raising and orienting fans are critical on Montreal flat roofs.
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Schedule annual HVAC maintenance : cleaning the evaporator, flushing the rooftop condenser, checking tightenings and updating comfort settings.
Deadlines and coordination
This type of HVAC installation is generally completed in one day : morning for tracing, drilling and installing the frame; afternoon for refrigeration, electrical, vacuum and commissioning. Coordination with the building manager/syndic is anticipated (roof access, protection of circulation).
Why AirGreen for your project in Greater Montreal?
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Proven local expertise on flat roofs ( Montreal , Laval , Longueuil , North Shore , South Shore ).
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Careful execution : durable supports, waterproof finishes, complete adjustments upon commissioning.
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Support for subsidies when the equipment and the file allow it.
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Attentive after-sales service : Our HVAC maintenance visits extend lifespan and maintain seasonal performance.
What's next?
The system installed today is scalable: adding a second head if an additional room or floor needs to be air conditioned/heated, integrating smart controls (Wi-Fi), and an annual maintenance plan. In the Plateau, as elsewhere in Greater Montreal, we provide clean, sustainable solutions that are perfectly suited to the local architecture.
Summary sheet — Plateau-Mont-Royal installation
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Type : Zephyr wall-mounted heat pump (residential range).
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Context : mounting on flat roof with raised galvanized frame and anti-vibration .
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Route : short refrigeration connections (≈ 3–5 m) via sealed technical cap.
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Electrical : dedicated power supply, chassis disconnect box .
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Objective : 4-season comfort, preserved aesthetics, easy maintenance.
Are you considering a similar HVAC installation in Montreal , Laval , Longueuil , on the North Shore or South Shore ? Contact us: a technical visit is sufficient to validate the capacity, the layout and the feasibility of possible subsidies.