A flat roof installation designed to last, quiet and compliant with HVAC best practices
Project background
At AirGreen , we were contacted by a co-owner of a residential building located in Côte-des-Neiges–Notre-Dame-de-Grâce . The goal: to add a high-performance wall-mounted heat pump to ensure four-season comfort without cluttering the facade. The choice was a Gree Livo R32 , a recent single-zone unit operating with R-32 refrigerant, appreciated for its stable performance and ease of maintenance.
Site characteristics and implementation strategy
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Flat gravel roof with technical access: ideal for installing the condenser away from view and noise pollution.
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Short route of refrigeration connections to the apartment's technical column, limiting pressure losses and improving seasonal efficiency.
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Protected facade : no footprint on the ground or balcony, which complies with the condominium regulations.
We prefer installation on a roof support : galvanized steel frame fixed on treated logs placed on the gravel, guaranteeing load distribution and impeccable stability. Anti-vibration pads and an expansion loop (service loop) on the refrigeration lines reduce the transmission of vibrations to the structure.
Installed device and technical characteristics
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Brand / Range : Gree – Livo R32 (single-zone).
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Type : wall-mounted heat pump (mini-split).
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Refrigerant : R-32 with low GWP compared to R-410A.
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Operating range : adapted to Montreal 's climate, with optimized winter heating mode and automatic defrosting.
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Sound level : discreet condenser, particularly relevant in dense urban environments (CDN-NDG, City of Montreal ).
For homes in Montreal, Laval, Longueuil, North Shore and South Shore , this single-zone architecture offers an excellent comfort/consumption ratio when a single space needs to be treated efficiently.
Installation details visible on site
Supports and clearances
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Frame on logs : two treated wooden logs support the metal support, ensuring flatness and durability on gravel.
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Clearances maintained around the condenser for air intake/discharge, simplifying HVAC maintenance and snow removal.
Refrigeration connections and sealing
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Short route (≈ 6–8 m) between condenser and technical column.
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Continuous UV insulation of lines (return and liquid) with finishing tape; expansion loop limiting mechanical fatigue.
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Roof penetration via a waterproof metal box/flashing : vapor barrier, peripheral mastic and cable glands for perfect water and air tightness .
Power supply and compliance
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Dedicated 240V circuit from the dwelling unit panel, adequate protection; service switch near the condenser on the roof.
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Grounding verified and sheathed wiring meets RBQ/CSA requirements.
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Commissioning tests : vacuum < 500 microns, pressurized nitrogen test, leak test, load adjusted according to actual length.
Interior: targeted comfort and careful aesthetics
The wall-mounted head is positioned to evenly sweep the living area while avoiding direct airflow. The lines are aligned with the service column; condensate is drained by gravity to the outside, eliminating the risk of pump noise and reducing maintenance.
Why the Gree Livo R32 for this type of installation?
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Efficiency : very good cooling and heating performance for well-insulated apartments.
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R-32 : better volumetric efficiency and reduced climate impact compared to R-410A.
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Silence : discreet condenser and evaporator, perfect for dense residential areas ( Montreal intramural ).
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Service and parts : local availability, simple HVAC maintenance thanks to a proven architecture.
Progress of the work (chronology)
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Technical validation with the co-ownership union (location on roof, routing of lines, access).
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Roof protection and support installation: checking slopes and flow points.
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Controlled drilling of the slab/roof and installation of the metal flashing .
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Passage of refrigerant connections and control wiring; continuous insulation and expansion loop .
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Electrical connections on dedicated circuit and installation of proximity switch.
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Pressure tests , vacuum drawing, valve opening, commissioning and fine tuning (flow rates, silent mode, temperature monitoring).
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Submission of a commissioning report with key measurements and maintenance instructions.
Result: comfort, silence and energy efficiency
The customer immediately benefits from precise comfort in summer and winter, quiet operation and controlled consumption . The condenser located on the roof frees up the facade and avoids nuisances for the neighborhood. The whole thing complies with current standards and remains easy to maintain : winter defrosting, cleaning of the coils, rinsing of the interior filters and annual inspection.
Recommended preventive maintenance
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Clean filters every 4 to 8 weeks depending on usage.
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Annual inspection by an AirGreen technician: leak check, gentle chemical washing of the coils, verification of blowing intensities and temperatures.
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Condenser clearances : Keep 60–90 cm free and clear snow around the edges to maintain performance in extreme cold.
Points of attention and pitfalls to avoid (AirGreen feedback)
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Improvised supports : a condenser placed directly on the gravel ends up destabilizing and damaging the membrane. We use a dedicated frame on logs with anti-vibration pads.
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Leaky penetrations : Without flashing and vapor barriers, moisture can seep in. Our sealed metal enclosure protects the roof and connections.
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Too long line : Making the route short and straight preserves the refrigerant charge and seasonal efficiency.
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No disconnect : The service switch within reach of the technician is essential for safety and compliance.
Grants and Compliance
When the wall-mounted heat pump chosen is ENERGY STAR certified with cold weather heating performance, certain local financial assistance may apply depending on the program in effect and the configuration. Our team verifies eligibility at the time of the quote for our customers in Montreal, Laval, Longueuil, North Shore and South Shore .
What the customer remembers
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A clean construction site, a preserved roof, and a durable HVAC installation .
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An efficient, discreet and easy to maintain R-32 device.
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A turnkey AirGreen service : advice, installation, commissioning and monitoring.
Are you considering a wall-mounted heat pump on a flat roof in Montreal or the suburbs? Our teams respond quickly in Laval , Longueuil , on the North Shore and the South Shore with solutions adapted to your building and your co-ownership regulations.