Installation of a Gree wall-mounted heat pump on a flat roof in Plateau-Mont-Royal
On a typical flat roof in the Plateau-Mont-Royal neighbourhood, AirGreen installed a Gree wall-mounted heat pump with an outdoor condenser mounted on a stable and quiet elevated support. The result: an efficient system in both winter and summer, discreet for the neighbourhood, and perfectly suited to the realities of Montreal's urban buildings.
In summer, the outdoor unit rejects the house's heat outside.
Generic illustration of this type of installation, not a survey of this job site. Tap a number.
Mounted level on a wall plate, high enough for the air to reach the whole room, with enough space around it to slide the filters out easily.
The refrigerant lines, the communication cable and the drain go through the wall in a single opening, sealed against water, cold air and insects.
Two insulated copper pipes connect the two units. Outside, a line cover can protect them from sun, knocks and weather.
A shut-off switch near the outdoor unit isolates it safely for service. It must stay accessible at all times.
The compressor and the fan. In heating mode it captures heat from the outdoor air, even in winter, and moves it inside.
On the ground or on the wall, it keeps the unit above accumulated snow. The unit stays clear and defrost water can drain away.
The fan needs to blow freely. Storage, a fence or a wall too close, and efficiency drops while noise goes up.
In the Plateau-Mont-Royal neighbourhood, many flat-roofed buildings are seeking to improve comfort without adding further visual impact to their already heavily used façades. In this project, our AirGreen team installed a Gree wall-mounted heat pump with its outdoor condenser mounted on the roof, away from the street and neighbours, while remaining easily accessible for maintenance.
Context: a typical Plateau building
The building is a condo/plex-style residential building surrounded by mature trees and other multi-story buildings. The client wanted:
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Heating and cooling your unit efficiently all year round
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Avoid placing the device on the ground in the already limited courtyard.
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Minimize the noise perceived by the occupants and the neighborhood.
We therefore proposed a high-efficiency Gree wall-mounted heat pump, of approximately 12,000 BTU , perfectly suited to the size of the unit and the realities of the Montreal climate.
A Gree wall-mounted heat pump designed for the Quebec climate
The Gree wall-mounted heat pump chosen for this project offers:
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Efficient heating in winter , with an inverter compressor capable of maintaining good capacity even in cold weather.
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Stable and quiet air conditioning in summer
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An excellent compromise between comfort, energy efficiency and reliability
From the inside, the wall unit diffuses a homogeneous air and allows the customer to enjoy a pleasant temperature in all seasons, while reducing their dependence on electric baseboard heaters.
Installation of the outdoor unit on the flat roof
The photo shows the Gree outdoor unit installed at night on the building's flat roof. Several key elements of the installation were carefully planned:
1. Elevated support and membrane protection
The device rests on a galvanized steel support , itself fixed to two treated wooden beams placed on the roof membrane. This configuration allows:
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To raise the unit above the snow and ice accumulations
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To distribute the load so as not to damage the membrane
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To maintain good stability, even in strong winds
We use appropriate shims and anchors to comply with roof constraints and manufacturer recommendations.
2. Vibration and noise management
Vibration dampers are installed under the unit to limit the transmission of vibrations to the building structure. This is essential in a dense urban environment like the Plateau:
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Less noise for the occupants of the apartment directly below
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A better experience for the neighbors, especially at night
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Increased lifespan of mechanical components
3. Routing of refrigerated lines
The refrigeration lines, communication cable, and drain are bundled together and neatly secured along the parapet. We use:
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UV and weather resistant insulation
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Sturdy fasteners to prevent the pipes from flapping in the wind
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A layout that maintains sufficient clearance for rooftop traffic
The whole thing joins the indoor unit located below, following the shortest possible path in order to optimize the system's efficiency.
4. Secure power supply
Near the unit, you can see the electrical disconnect box, which conforms to current standards. It ensures:
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A quick shutdown point for maintenance or emergency interventions
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Adequate protection against the elements
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Complete coordination with the building's electrical panel
This step is crucial for the safety of the occupants and our technicians.
Performance and reliability on an urban rooftop
Installing an outdoor heat pump on a flat roof in an urban environment has several advantages:
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Excellent air circulation : no immediate obstruction around the unit, which improves efficiency.
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Less risk of vandalism or accidental impacts , compared to a ground-based installation.
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Reduction of perceived street noise : the condenser is further away from neighbors' windows.
We are also planning accessibility for future maintenance: safe passage, clearance around the unit, clear marking of the circuit.
Before leaving the construction site, our team carries out the following:
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A thorough evacuation of the refrigeration circuit
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Checking pressures and temperatures in heating and air conditioning mode
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Automatic defrosting and condensation water drainage tests
Thus, the system is ready to face the harsh winters of Plateau-Mont-Royal, while offering optimal comfort from the first warm days of spring.
The AirGreen approach in Plateau-Mont-Royal and throughout Montreal
For this project, as with all our projects, we support the client at every stage:
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Needs analysis : area to be air-conditioned, insulation, lifestyle habits, architectural constraints.
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Recommendation of the right capacity and the right location (indoor and outdoor).
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Careful installation , respecting the standards and aesthetics of the building.
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Complete commissioning , with explanation of operation, modes and correct settings to save energy.
We also offer maintenance contracts to ensure the longevity of the Gree wall-mounted heat pump: cleaning of the indoor unit, inspection of the outdoor unit on the roof, verification of connections and parameters.
Do you live in a flat-roofed building in the Plateau or elsewhere in Montreal?
If you live in a condo or a plex with a flat roof, as is common in Plateau-Mont-Royal, a Gree wall-mounted heat pump installed on the roof is often the ideal solution:
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4-season comfort
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Discreet and silent installation
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Better energy efficiency than traditional systems
Contact us at AirGreen: we will be happy to assess your project and offer you a tailor-made solution, perfectly adapted to your building and the Montreal climate.
How it goes, from the first call to the end
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
Model, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
Floors and furniture protected, wall plate position marked level, wall opening located.
A single opening, with the slope the drain needs to flow outside.
Set on a stand raised above the snow, with the clearances the manufacturer requires.
Connected, insulated and protected. The opening is then sealed against water, cold air and insects.
A dedicated circuit and an accessible disconnect near the outdoor unit.
Leak test, vacuum, then start-up and a check of heating and cooling.
Remote, modes, filters: we show you the essentials before we leave.
- The on-site estimateWe look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
- The quoteModel, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
- Getting readyFloors and furniture protected, wall plate position marked level, wall opening located.
- The wall openingA single opening, with the slope the drain needs to flow outside.
- The outdoor unitSet on a stand raised above the snow, with the clearances the manufacturer requires.
- Lines, cable and drainConnected, insulated and protected. The opening is then sealed against water, cold air and insects.
- The electrical workA dedicated circuit and an accessible disconnect near the outdoor unit.
- Tests and start-upLeak test, vacuum, then start-up and a check of heating and cooling.
- The walkthroughRemote, modes, filters: we show you the essentials before we leave.
And at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
Conversion: 1 W = 3.412 BTU/h. An indication, not a load calculation: baseboards and furnaces are often stronger than the real need, and they can stay as backup. AirGreen confirms the capacity on site.
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Clean the indoor unit's filters.
- Clear leaves and debris left on the outdoor unit by winter.
- Test cooling before the first hot days.
- Clean the filters more often when the unit runs a lot.
- Keep plants away from the outdoor unit.
- Check that no water drips from the indoor unit.
- Rake the leaves around the outdoor unit.
- Test heating before the first cold days.
- Book periodic maintenance before winter.
- Keep snow away from the stand and the front of the unit.
- Let the unit defrost: it is normal.
- Never hit the ice on the fins; call us if the unit stays iced up.
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What people ask us about this kind of work
Does a wall-mounted heat pump heat in winter?
Wall-mounted or multi-zone: how do I choose?
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How cold can it heat?
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The outdoor unit is covered in ice: is that normal?
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Text and photo: a real AirGreen Climatisation & Chauffage job. The diagrams are generic illustrations of the type of installation, not a survey of this job site. Sources of the added figures: airgreen.ca product pages (NEEP / AHRI performance), Hydro-Québec (Heat pumps page, LogisVert, read on 13 October 2026), Régie de l’énergie (rate D as of 1 April 2026).