For this project in the Plateau-Mont-Royal neighbourhood, our team was tasked with installing a Gree wall-mounted heat pump with an outdoor condenser positioned on the building's flat roof. Since it's a multi-unit building, the roof is already occupied by various mechanical equipment: every detail of the installation is crucial for performance, durability… and the comfort of the residents.
A Gree wall-mounted heat pump for an urban dwelling
The chosen system is a Gree Inverter wall-mounted heat pump , with a capacity of approximately 12,000 to 18,000 BTU, perfectly suited to a typical condo or apartment in the Plateau neighborhood. Inside, one or more wall-mounted units provide heating and cooling for the living areas; outside, the Gree condenser, visible in the photo, either expels or absorbs heat depending on the season.
Thanks to Inverter technology:
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The power is continuously adjusted according to the actual demand.
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The on/off cycles are reduced, which improves comfort and longevity.
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Electricity consumption is lower compared to a conventional air conditioner or electric heater.
For a dense neighbourhood like the Plateau, where space is limited and Hydro-Québec meters climb quickly, this solution is particularly interesting.
Rooftop installation: constraints and advantages
Installing a wall-mounted heat pump condenser on a flat gravel roof, rather than on the ground in a yard, offers several advantages:
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No encroachment into the narrow alleys or courtyards , often already well occupied by ferries, bicycles and parking spaces.
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Reduction of perceived noise in living areas and for neighbors, as the roof provides a natural distance.
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Increased security , as the device is out of reach of accidental impacts and acts of vandalism.
But this also implies significant technical constraints: the roof membrane must be protected, the unit stabilized despite the wind, safe access for maintenance must be ensured and clearances around other equipment must be respected.
An elevated, stable support that respects the roof
The photo shows that the Gree condenser is installed on a raised aluminum stand , itself placed on two pieces of treated wood resting on gravel. This setup is not improvised; it serves several specific purposes:
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Distribute the unit's load over a larger area to avoid puncturing the membrane.
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Raise the device above the level of gravel and rainwater to prevent premature corrosion.
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Facilitating defrosting in winter: ice and water melting under the unit can flow freely without touching the bottom of the casing.
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Limit the vibrations transmitted to the structure by combining a rigid chassis and anti-vibration pads.
We always ensure that the supports and crossbeams used are compatible with the requirements of roof engineering (weight, wind, slope, water paths).
Refrigeration line and insulation management
At the rear of the condenser, the insulated refrigerant lines connecting to the wall-mounted units inside are visible. On a rooftop installation, we pay particular attention to these elements:
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Use of UV-resistant insulation to prevent the sun from weakening the sheath over time.
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Neat and secure installation along traffic routes so as not to create an obstacle for other work on the roof.
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Optimized line length to limit pressure losses and comply with Gree recommendations.
The power and communication cabling is also securely fixed and protected against abrasion on the gravel.
Air circulation and spacing between units
We noticed several condensers on the roof belonging to other dwellings. When installing a heat pump on a flat roof, we always check:
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The clearances at the rear and front of the condenser ensure good air circulation.
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Lateral spacing between the different units, so that they do not harm each other, especially during periods of heatwave.
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The orientation in relation to obstacles (walls, parapets, other mechanical equipment) to limit the recirculation of hot air.
A condenser that breathes well is a system that maintains its efficiency, consumes less and lasts longer.
Future maintenance and safety of personnel
We are also thinking about long-term maintenance :
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The raised support allows a technician to easily pass under or around the unit to perform inspections, cleaning of coils and verification of fittings.
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The alignment of the equipment leaves a safe passage corridor for maintenance personnel, without having to step over lines or supports.
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The required labels and codes (including the AirGreen sticker) remain visible to quickly identify the installation and trace its history.
All of this translates into faster, therefore less costly, interventions, and a system that is better monitored over the years.
AirGreen: Your rooftop heat pump expert in Montreal
This project in Plateau-Mont-Royal illustrates our expertise when it comes to installing Gree wall-mounted heat pumps on roofs in urban buildings: condos, plexes, small rental buildings.
Our approach:
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Analysis of the roof structure and access constraints.
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Choosing the right Gree tonnage according to the surface area, orientation and insulation of the dwelling.
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Installation on suitable supports, respecting the membrane and clearances.
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Complete commissioning, functional tests in heating and air conditioning, detailed explanations to occupants.
Whether you are in Plateau-Mont-Royal, Rosemont, Villeray, the Southwest or elsewhere in Greater Montreal, we can transform your flat roof into a high-performance technical space for your heat pumps – without sacrificing reliability or resident comfort.
Contact AirGreen for an evaluation of your project: we will be happy to offer you a tailor-made solution with Gree systems and other major brands that we distribute.