Installation of a Gree wall-mounted heat pump on a flat roof in Verdun
AirGreen installs a Gree wall-mounted heat pump on a flat roof in Verdun. HVAC expertise for Montreal, Laval, Longueuil, the North Shore, and the South Shore, with optimal performance and subsidies.
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The job on one screen
The article, chapter by chapter
An optimized HVAC installation project for a residential building
At AirGreen , we recently completed a Gree wall-mounted heat pump installation on the flat roof of a residential building in Verdun , a rapidly evolving neighborhood of Montreal. The project was distinguished by a technical challenge: integrating the outdoor units onto a white, wind-exposed roof, while ensuring lasting stability and optimal performance in all seasons.
A strategic choice: the Gree heat pump for lasting comfort
The owners opted for a Gree wall-mounted heat pump , known for its reliability and performance even during the harsh winters of Greater Montreal. The advantages are clear:
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High energy efficiency , reducing power consumption.
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Heating performance down to -25°C, ensuring constant comfort.
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Eligibility for grants available in Quebec for Energy Star certified equipment.
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Increased durability , essential for a system installed on the roof.
Technical details of flat roof installation
The installation required meticulous planning, as wall-mounted heat pump outdoor units must be properly secured and insulated on a roof to withstand climatic variations.
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Raised support made of treated wood and stabilizing blocks , to protect the roof and avoid any direct contact with the membrane.
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Wiring and piping protected by white capping , in harmony with the roof and ensuring optimal insulation of the refrigerant pipes.
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Gravity drainage of condensates, simplified by the slight slope of the roof.
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Two outdoor units installed , each supplying a separate indoor area, a perfect choice for a multi-unit building.
Constraints encountered and solutions provided
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Roof working height : our technicians used secure access and anchoring systems to comply with safety standards.
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Wind exposure : Raised supports have been reinforced to prevent excessive vibration.
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Length of refrigerant lines : The distance between the outdoor units on the roof and the indoor heads required careful insulation to maintain energy efficiency.
Why choose AirGreen for this type of project?
Flat roof installation requires specific technical expertise that few companies possess. At AirGreen, we:
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We evaluate each project according to the building configuration.
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We only use supports and accessories that comply with Quebec HVAC standards.
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We offer a complete service including advice on provincial and federal subsidies (LogisVert, Maison plus verte).
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We guarantee RBQ certified work , carried out by qualified and experienced technicians.
End result: comfort and peace of mind
Thanks to this installation, residents now benefit from an efficient heating and cooling system that reduces energy costs and ensures consistent indoor comfort, while respecting the integrity of their roof. The Gree heat pump installed in Verdun perfectly illustrates our ability to adapt our HVAC solutions to Montreal's architectural specificities.
Conclusion
At AirGreen, each installation is designed to combine performance, durability and savings . This project in Verdun demonstrates our expertise in installing wall-mounted heat pumps on flat roofs, an effective solution adapted to Montreal's urban environment.
The job tools
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.
How the job unfolds
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.
What we check on a job like this one
Each number is a point we check on site. Switch between summer and winter to watch air and heat move.
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.
Is your home ready?
Check what applies at your place. A "no" is not a refusal: it is what we sort out during the estimate.
Good habits, once the unit is in place
Six simple habits that keep the unit going. Your list stays on this device.
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.
The right pages, at the right time
Four statements: true or false?
It all comes down to details you have just seen.
1. In heating mode, the outdoor unit can produce water.
During defrost cycles. That water must drain away without forming ice.
2. You pick the capacity with a simple square-footage rule.
Windows, insulation, orientation and how the room is used all count. Capacity is chosen on site.
3. A multi-zone connects several indoor heads to a single condenser.
One head per room, all on the same condenser. Each room keeps its own temperature.
4. The disconnect can sit behind the patio furniture.
It must stay accessible: it is what shuts the unit off for service.
0 / 4 right answers
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?
Where does the outdoor unit go?
Are there grants?
Do I need a permit?
How cold can it heat?
How much can I save?
How is the LogisVert assistance calculated?
Is it noisy?
The outdoor unit is covered in ice: is that normal?
Does AirGreen hold the required licences?
Is the estimate free?
No question matches. Write to us: we answer.
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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).