Installation of a Gree Livo R32 wall-mounted heat pump in Saint-Laurent (Montreal)

Two flat-roof units, short distances and sustainable performance for a Montreal plex
At AirGreen , every HVAC installation is designed for the realities of Montreal's buildings: flat roofs, limited technical access, extreme climates, and maintenance requirements. In Saint-Laurent, we installed two Gree outdoor units from the Livo R32 range on a flat roof covered with granules, serving two separate dwellings. The goal: four-season comfort while protecting the roof membrane and maximizing seasonal efficiency.

The context of the building and the needs expressed

Typical flat-roofed residential building: ventilation vents, low parapets, shared service shaft. Occupants reported:

• Heat spikes in open areas in summer;

• Efficient supplemental heating needs at the beginning and end of winter;

• A wish for silence and energetic sobriety;

• A preference for installation on the roof in order to free up the courtyard and avoid any visual impact on the facade.

Both homes have similar living areas. Dimensioning by thermal load confirmed the relevance of single units of 12 to 18 kBTU each depending on the surface area and exposure. The Gree Livo R32 range meets these criteria thanks to its inverter modulation and its performance in extreme cold .

Why the Gree Livo R32 for Saint-Laurent

• R-32 refrigerant : better volumetric efficiency and reduced GWP compared to older generations;

• Inverter compressor : stable maintenance of the setpoint without over-consumption;

• Cold operation adapted to Montreal winters;

• Compact and quiet indoor units, washable filters, night mode;

• Easy maintenance, quick parts availability.

Installation on a flat roof: membrane protection and vibration control

The two capacitors are placed on aluminum supports anchored to distribution pads (ski-type rails) which rest on the membrane with a protective underlay . This configuration:

• Maintains watertightness : no structural perforation, distributed loads;

• Provides sufficient elevation to facilitate rainwater drainage and, in winter, defrosting ;

• Reduces vibration transmission thanks to anti-vibration pads ;

• Maintains free airflow around appliances to protect performance.

The units are aligned parallel to the roof edge and away from obstacles (vents, guardrails) to avoid re-blowing and guarantee nominal capacity during hot periods.

Careful refrigeration process and controlled lengths

We favor short routes to limit pressure losses:

• 1/4"–3/8" insulated copper connections conforming to the range specifications;

• UV duct on the roof to protect connections from bad weather and UV rays;

• Waterproof penetrations in the membrane (sleeve, flashing, compatible sealant) opening into the inner sheath;

• Bending radius respected to avoid damaging the flares .

Each circuit remains within the manufacturer's recommended length range ; no refrigerant top-up is required. Communication cables and power are routed separately from the refrigerant lines to facilitate maintenance and avoid interference.

Condensate management: priority to gravity

On the inside, the condensate drain is installed with a continuous slope towards the outside, which eliminates the need for a condensate pump :

• Less noise and points of failure;

• Simplified maintenance (periodic rinsing);

• Reduced risk of infiltration thanks to a watertight connection .

On the roof, defrost water discharges have a clear flow path , away from traffic areas, to prevent the creation of ice in cold weather.

Power supply and safety

• Dedicated circuits for each unit, from the housing panels;

• Disconnect boxes installed nearby, weatherproof enclosures;

• Grounding and protections sized according to the nominal intensity;

• Routing in compliant conduits, with clear identification of each line.

Commissioning: the AirGreen signature

Our commissioning protocol guarantees performance from day 1:

1. High pressure nitrogen testing and leak testing on each circuit;

2. Deep vacuum (< 500 microns) with stabilization and ascent test;

3. Checking intensities , blowing temperatures, superheating and subcooling ;

4. Calibration of interior shutters for effective diffusion in open areas;

5. Setting eco modes and seasonal usage recommendations.

What you see in the picture… and what it means for sustainability

• Two independent raised supports : better vibration dissipation and easier maintenance;

• Wooden rails protected under the supports: load distribution and respect for the membrane;

• Black chute on the roof edge: protected connections, straight route;

• Peripheral clearance : unobstructed airflow to maintain nominal efficiencies ;

• Clear technical access : secure inspections and interventions.

Results for occupants

• Uniform thermal comfort in living areas;

• Quiet operation thanks to inverter modulation and good speed adjustment;

• Lower consumption compared to window air conditioners or electric space heaters;

• Improved air quality through washable filters and scheduled maintenance.

AirGreen Best Practices for Flat Roofs in Montreal

• Raise units 12-18 in and maintain 30-45 cm of clearance;

• Direct the blowing away from parapets and obstacles;

• Protect each penetration (flashing + membrane-compatible sealant);

• Draw continuous UV ducts and secure cables;

• Provide a drainage path for defrosting ice;

• Implement an annual HVAC maintenance plan , with pre-winter inspection.

HVAC maintenance: maintaining efficiency over time

AirGreen offers planned tours:

• Cleaning/disinfection of internal exchangers, tanks and filters;

• Control of the gravity drain (slope, clogging);

• Checking tightening torques and electrical connections;

• Inspection of the exterior insulation and repair of the ducts if necessary;

• Recording of refrigeration parameters to monitor seasonal changes.

This monitoring preserves the warranty and maintains high seasonal performance , essential for realizing real savings.

Grants and administrative support

High-efficiency R-32 wall-mounted heat pumps are generally eligible for assistance programs applicable in Quebec, subject to technical criteria and envelope availability. Our team assists households in Montreal, Laval, Longueuil, the North Shore, and the South Shore to verify eligibility and optimize applications .

Why entrust your project to AirGreen?

• Local expertise on flat roofs and the specific features of the Saint-Laurent real estate portfolio;

• Rigorous methodology: load calculation, short paths, deep vacuum , pressure tests;

• Aesthetics and durability : suitable supports, UV channels, membrane protection;

• Responsive after-sales service and structured HVAC maintenance throughout Greater Montreal.

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In short
Two Gree Livo R32 wall-mounted heat pumps on a flat roof in Saint-Laurent, installed on raised supports with sealed penetrations , short cooling paths and meticulous commissioning . Comfort is immediate, consumption is controlled and the roof is protected over time — the AirGreen brand.