On the flat roof of a residential building in Mercier–Hochelaga-Maisonneuve , our team completed the full installation of a Sharp multi-zone wall-mounted heat pump system. The goal: to provide year-round comfort to several apartments, while optimizing the use of roof space and protecting the equipment from the harsh Montreal climate.
A typical HoMa context: apartment building and technical roof
The building is a brick duplex with several stacked apartments. As is often the case in this area:
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The backyard is small and already very busy.
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The facades are used for balconies, exterior staircases and access points.
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The roof naturally becomes a technical space for ventilation and air conditioning systems.
The building already features metal chimneys, roof fans, and ventilation ducts . Our challenge: to integrate a new Sharp heat pump system without obstructing traffic flow, while respecting safety clearances and roof drainage.
System choice: Sharp multi-zone wall-mounted heat pump
To serve several rooms (or several dwellings depending on the interior layout), we opted for a system:
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Sharp multi-zone wall-mounted heat pumps ,
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Based on an external Sharp Multi-Zone TU R-32 type capacitor,
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With an overall power output of approximately 30,000 BTU , suitable for a set of 2 to 3 wall heads.
This type of system offers several advantages for a building like this one:
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A single outdoor unit (or a limited number) for multiple air conditioning and heating zones.
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An inverter technology that continuously modulates power, reducing electricity consumption and temperature variations.
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The R-32 / A2L refrigerant, more energy efficient and with a reduced global warming potential compared to R-410A.
The Sharp wall-mounted heads installed inside ensure precise comfort in each area : living room, bedrooms, main living area, etc.
A flat rooftop installation designed for Montreal's climate
In the photo, you can clearly see:
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A large Sharp unit mounted on a wood and metal frame ,
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A second, more compact outdoor unit, placed directly on the gravel,
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The whole thing is installed on a flat roof covered with ballast and natural vegetation.
This is not simply a "depot" of devices: every detail has been carefully considered.
1. Elevated support and stability
The main Sharp unit rests on a raised base made of treated wood and metal legs :
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This raised platform protects the device from accumulated snow , standing water, and debris.
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It allows free flow of roof drainage , avoiding stagnant areas under the unit.
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It facilitates maintenance: the technician can easily access the base and connections.
The anchors are designed to withstand the strong winds frequently encountered on flat roofs, while also protecting the roofing membrane.
2. Optimal air circulation
The units are positioned:
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At a safe distance from guardrails, low walls and other equipment (roof vents, chimneys),
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In order to leave sufficient clearance around the heat exchangers , which is essential for performance.
Poor air circulation can drastically reduce heating and cooling capacity. Here, the chosen location allows the Sharp condensers to breathe freely , even in the middle of a heatwave.
3. Management of refrigeration lines and food supply
Refrigeration pipes, communication cables, and power supplies are neatly routed from the apartments to the roof. We ensure that:
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Insulate the lines properly to limit heat loss.
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Protect them from UV rays, wind and snow with suitable covers.
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Position the fittings and junction boxes in accessible but discreet areas.
The result: an installation that is both visually clean and easy to maintain .
Winter performance: a crucial point for Montreal
Installing a heat pump on a flat roof in Montreal requires special attention during the winter:
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The selected Sharp multi-zone units are designed to operate at low temperatures , with excellent performance even below freezing.
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The clearance under the condensers allows blown snow and ice to avoid blocking the fans or drains .
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Technical access is planned: technicians can intervene safely, even in cold weather, for maintenance or troubleshooting.
Thanks to these precautions, the system ensures efficient heating for much of the winter, significantly reducing reliance on baseboards or electric central heating.
Four-season comfort for the occupants
Inside, the occupants are now enjoying:
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Efficient and quiet air conditioning during hot periods, particularly appreciated in top-floor apartments which are often more exposed to the sun.
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Energy-efficient heating in spring, autumn and winter, with a stable and pleasant temperature.
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With zone-by-zone management, allowing comfort to be adapted according to room occupancy.
Sharp heat pumps offer different modes (heating, cooling, dehumidification, ventilation, eco, standby, etc.), giving residents great flexibility.
AirGreen's expertise for Montreal's flat roofs
This type of project perfectly illustrates our approach at AirGreen:
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Building analysis : type of structure, access to the roof, configuration of the dwellings.
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Equipment choice : here, a Sharp multi-zone wall-mounted heat pump, perfectly suited to an urban multi-unit building.
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Careful installation on the roof : raised supports, membrane protection, clearances respected, snow and wind management.
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Monitoring and maintenance : recommendations to owners for minimum snow removal around units and planning of periodic maintenance.
Whether in Mercier–Hochelaga-Maisonneuve or elsewhere in Greater Montreal, our objective remains the same: to offer a turnkey, reliable, aesthetic and sustainable solution , adapted to the architectural and climatic realities of the region.
Do you have a flat roof in Montreal, Laval or on the South Shore / North Shore?
If you own a building with a flat roof and you wish to:
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Upgrade your air conditioning system,
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Add a high-performance auxiliary heater,
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Or equip several dwellings with a centralized heat pump solution,
We can offer you a Sharp or other brand solution that is suitable and specifically sized for your building.
Contact us: we will assess your roof, your access constraints, your power needs and your comfort and energy saving objectives.