Installation of a Gree (R-32) wall-mounted heat pump in Saint-Laurent

A flat roof installation designed to last, quiet and ready for Montreal winters

Project context and client objectives

In Saint-Laurent, a homeowner wanted to modernize hisheating and air conditioning system to improve year-round comfort, reduce his energy bill, and limit noise impact on the facades. We offer a Gree wall-mounted heat pump with R-32 refrigerant , a relevant choice for its performance in cold climates, its low GWP, and its rapid availability in Greater Montreal .

Why a Gree R-32 wall-mounted heat pump?

• Energy efficiency : Recent Gree R-32 units offer very good SEER/HSPF and stable performance in mid-season and mid-winter.

• 4-season comfort : efficient heating in cold weather and gentle air conditioning in summer.

• New generation refrigerant : less environmental impact than R-410A.

• Simplified maintenance : easy access to the interior head filters and condenser components.

Flat roof installation: our technical choices

• Support : condenser placed on roof rails with anti-vibration pads to protect the elastomer membrane and eliminate sound transmission into the building.

• Raising : raised chassis (> 12") to free the unit from runoff water and snow accumulation.

• Clearances : respect the clearances around the device to ensure optimal airflow and safe maintenance.

• Refrigeration connections : continuously insulated piping , UV protected by white sheath; direct routing to the technical column to reduce pressure losses.

• Electrical : Dedicated power supply and external isolation (near the condenser) in accordance with the Code, with wiring protected from UV and punctures.

• Waterproofing : penetrations sealed with membrane-compatible mastic and mechanical flashings to maintain the integrity of the roof.

• Condensate management : gravity drainage inside the evaporator side; no free discharge onto the roof, avoiding icing and risks to the membrane.

Key steps in HVAC installation

1. Technical visit : taking measurements, identifying the best route (technical column), validating clearances and the electrical connection point.

2. Installation of the support : weighted/anti-vibration rails, checking of slopes and existing drainage.

3. Drilling and laying of lines : dehydrated copper, brazing under nitrogen, nitrogen pressure test followed by deep vacuum drawing .

4. Connections : refrigeration connections, communication cabling, power supply, grounding .

5. Commissioning : control of overheating/subcooling, verification of intensities, calibration of heating/air conditioning modes.

6. Customer provided with : operating instructions, HVAC maintenance and maintenance schedule.

Results: comfort, silence and savings

• Noise reduction thanks to the anti-vibration support and the distance from the facades.

• Stable temperatures in the rooms served, even during the rapid variations typical of Montreal.

• Increased energy efficiency compared to an old cooling-only air conditioner.

• Preserved aesthetics : no unity on the facade; clean and discreet paths.

Recommended maintenance (to maximize longevity)

• Clean the inner head filters every 4 to 8 weeks during the season.

• Annual inspection : pressures, fans, condensate trays, electrical tightening, condition of the roof membrane around the crossings.

• Winter Clearance : Keep the unit free of blown snow; never obstruct the suction.

• AirGreen Program : tailored HVAC maintenance contracts (residential and small commercial) to maintain performance and warranty.

Potential Grants and Eligibility

Depending on the capacity (BTU) and the efficiency of the chosen range, a recent R-32 wall-mounted heat pump may be eligible for provincial and municipal assistance. We verify for each address in Greater Montreal (Montreal, Laval , Longueuil , North Shore , South Shore ) and assist in setting up the file (proof of installation, AHRI number, detailed invoices).

Common pitfalls to avoid on flat roofs

• Rigid supports placed directly on the membrane: risks of punching and noise; prefer elastomer pads .

• Unsealed crossings : possible infiltration; use materials and techniques compatible with the membrane.

• Too long journeys and unnecessary loops : load losses and reduced efficiency; aim for a short, straight route .

• Condensate discharges on roofs : icing in winter; favor controlled evacuation.

Why AirGreen for your project in Saint-Laurent (and throughout Greater Montreal)

• Specialists in flat roofs and local urban constraints.

• Selection of proven brands (Gree, Fujitsu, Midea, Sharp, etc.) in R-32 / R-454B .

• Technical transparency : precise sizing (thermal load, line lengths, electrical protections), AHRI documentation, and end-of-site photos.

• Local service : dedicated teams in Montreal , Laval , Longueuil , North Shore and South Shore , with realistic response times.

Are you planning a flat roof installation in Saint-Laurent or elsewhere in Greater Montreal?
Our advisors guide you from choosing the heat pump to applying for grants , with careful execution that complies with industry standards.