A discreet and efficient flat roof construction site in the heart of a Plateau plex
Client context and objectives
At AirGreen , we are working in a typical Plateau-Mont-Royal plex where the co-owners want four-season comfort without sacrificing the aesthetics of the interior courtyard or the tranquility of the neighbors. We propose the installation of two Gree wall-mounted heat pumps from the recent R-32 range , each dedicated to a separate living area (main room and bedroom on the courtyard side). The challenge: to optimize heating efficiency in cold Montreal weather, preserve the tranquility of the neighborhood and secure the work on a flat roof exposed to wind and snow.
Technical overview of the installation
We installed two compact outdoor units on roof supports (polymer and galvanized steel anti-vibration risers), providing sufficient ground clearance for drainage, snow removal, and membrane inspection. The refrigerant lines and communication cables ran through a gray UV capping installed on the surface up to the guardrail, then descended to the interior through the existing technical duct. A rigid, ventilated openwork wooden screen framed the area to break the line of sight from neighboring terraces and dissipate noise while respecting the necessary clearances for air intake and discharge.
Why a Gree R-32 wall-mounted heat pump on the Plateau?
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Seasonal Efficiency : New generation R-32 reduces refrigerant charge and improves energy efficiency compared to older R-410A systems.
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Reliable heating in cold climates : the chosen range maintains good capacity in the negative temperatures frequent in Montreal .
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Installation flexibility : the mini-split allows you to precisely treat priority areas without duct work.
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Reduced noise : variable speed fans and inverter compressor; the wooden screen reinforces acoustic discretion on the stage side.
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Program eligibility : high-performance and Energy Star wall-mounted heat pumps are generally eligible for incentives in effect in Quebec depending on the configuration and power; we support customers to validate eligibility according to Montreal, Laval, Longueuil, North Shore, South Shore .
Flat roof execution details
Supports, seals and membrane
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Distributed loads : each unit rests on wide-base bases to distribute the weight and preserve the elastomeric membrane.
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Anti-vibration : high-density rubber pads reduce transmission to building structures.
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Useful height : raised ≥ 6–8 in to prevent accumulation of rainwater and snow.
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Waterproofing : limited penetrations; when a passage is required, we use a roof pass-through with flashing and membrane-compatible mastic (no unprotected perforations).
Route of the links
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Route : straight gray capping on the roof, then descent to shelter behind a wooden screen and a metal guardrail.
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Estimated length : ~8 to 12 m per area, including the roof-wall route and the descent to the interior heads.
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Bending radii : respected to preserve the integrity of the insulated copper tubes.
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Condensate management : gravity drainage from the interior heads to the exterior; pump only if the architecture requires it.
Ventilation and clearances
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Rear and side clearance : space left behind each condenser to ensure air supply ; the wooden screen remains open and sized to avoid creating recirculation of hot air.
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Front clearance : free area for discharge and maintenance.
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Orientation : airflow directed away from neighboring terraces for optimal acoustic comfort .
Interior configuration and comfort
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Wall-mounted fans : positioned high on interior walls, adjustable horizontal and vertical diffusion to avoid direct air currents.
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Thermostats and remote controls : fine control of setpoints; eco modes and dehumidification during the off-season.
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Filtration : Quick-access washable filters; built-in maintenance reminder.
Safety, standards and longevity
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Electrical : Dedicated panel circuit breakers, compliant gauge and wiring; external disconnect box within service range.
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Refrigerant : vacuum, micron draw and nitrogen leak test before opening the valves.
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Winter : ground clearance, snow clearance in front of the batteries and automatic defrosting of the unit.
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Service : clear access on three sides for periodic HVAC maintenance (coil cleaning, current checking, support inspection).
Result: silence, performance and aesthetics respected
The Gree R-32 unit duo provides:
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responsive cooling in summer for the two main areas;
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economical heating during autumn, winter and spring;
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discreet integration thanks to the wood cladding and the careful path on the roof;
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easy maintenance access without encroaching on common areas.
AirGreen Best Practices on Flat Roofs in Greater Montreal
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Roof pre-inspection : we validate the slope, rainwater drainage and condition of the membrane to avoid any risk of water retention under the supports.
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Choice of supports : modular risers with wide support surfaces; never compression points.
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Wind management : urban over-roofing = wind stress ; we orient the condensers and brace the wooden screen.
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Clearances : absolute priority to heat exchange ; an aesthetic cover must never compromise airflow .
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Clean routing : continuous capping fixed at regular intervals; generous bending radii; no loose cables.
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Acoustics : anti-vibration decoupling, drip-loops and cables secured to eliminate unwanted noise.
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Snow plan : anticipation of accumulations; possibility of adding a snow guard if the environment requires it.
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Maintenance : washing of exterior coils, light disinfection of interior tanks, checking of pressures/probes at the start of each season.
What the customer actually gains
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Targeted comfort : each zone sets its own temperature; more stable sleep in the bedroom, and the living room always at the right temperature.
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Savings : the heat pump transfers heat efficiently; compared to conventional electric convectors, annual consumption is reduced.
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Real estate value : A clean, well-integrated HVAC system attracts buyers to the Plateau , where space is at a premium and aesthetics are important.
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Peace of mind : manufacturer warranties and AirGreen service; maintenance contract available to extend lifespan.
Maintenance tips (owners & property managers)
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Internal filters : rinse every 1–2 months during periods of heavy use.
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Exterior clearances : keep the openwork wooden screen, remove leaves and dust.
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Visual inspection : check the capping after high winds; contact us if a section lifts.
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Annual Visit : A complete HVAC maintenance (cleaning, electrical tightening, parameter reading) maintains seasonal efficiency .
Possible alternatives and extensions
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Multi-zone on a single outdoor unit if space becomes even more restricted.
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Ceiling cassette in an open area with no walls available.
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Air exchanger to improve air quality if natural ventilation is insufficient.
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Smart thermostats with weekly programming and consumption monitoring.
Deadlines and typical procedure
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Technical visit : distance measurements, electrical check, membrane assessment.
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Installation : generally in one day for two zones, including supports, connections, commissioning.
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Getting started : heating/cooling test, explanation of modes, advice on proper use .
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Assistance file : assistance for subsidies when applicable according to power, efficiency class and address (Montreal, Laval , Longueuil , North Shore , South Shore ).
Why AirGreen
We combine field engineering , aesthetic attention, and local service . Our teams understand the challenges of the Plateau-Mont-Royal 's alleys and flat roofs: sometimes narrow access, close neighbors, scheduling and noise constraints. We deliver a clean, durable HVAC system optimized for Montreal's climate.