A flat roof installation, designed for durability and service
The AirGreen method: performance, roof safety and efficiency in extreme cold
In the Villeray–Saint-Michel–Parc-Extension sector of Montreal, we installed a Sharp Eco Inverter wall-mounted heat pump on a flat roof typical of Montreal plexes. This type of installation requires a combination of respect for the membrane , load management , air clearances and impeccable service access . This is exactly what we do every day at AirGreen , throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore .
The equipment: Sharp, efficient and silent
The Sharp Eco Inverter with R-32 refrigerant is a modern wall-mounted heat pump , renowned for its high seasonal efficiency and stable heating during cold peaks. The DC inverter compressor precisely modulates power to maintain the temperature smoothly and limit consumption.
In terms of comfort, the condenser's acoustic architecture and electronic control ensure a low noise level , appreciated in Montreal's densely populated areas. Depending on the interior head configuration chosen, Sharp Plasmacluster™ technology contributes to better air quality .
Rooftop installation: principles and technical choices
Installing a wall-mounted heat pump on a flat roof isn't a simple translation of the ground-mounted installation. We apply specific principles:
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Membrane preservation : the condenser is placed on an aluminum frame resting on distribution rails . Under the rails, we use high-density insulating pads to diffuse the charge and eliminate any pressure points on the membrane.
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Usable height : the elevation of the chassis creates a sufficient air plenum for suction and prevents the accumulation of water, ice or gravel under the device.
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Discharge orientation : we orient the unit to avoid any recirculation of hot air towards parapets, low walls or vent outlets, which preserves efficiency in both summer and winter.
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Service access : front and side clearance optimized to allow maintenance operations (cleaning, pressure measurements, diagnostics).
Refrigerant and electrical path: cleanliness and robustness
The route of the lines is a major factor in performance:
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UV Insulated Refrigerant Lines : UV-resistant closed-cell insulation, capped and neatly tied to prevent wind lift.
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Controlled service loop **: a line reserve is left to facilitate future interventions without mechanical constraints on the expanders.
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Roof passage : sealed crossing with a dedicated box/flashing and membrane-compatible sealant, to prevent any infiltration.
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Power supply : accessible external disconnection near the condenser, wiring sized according to the nominal current and secure routing to resist UV and thermal cycles.
Condensate management: solutions adapted to the roof
A wall-mounted heat pump releases little water to the condenser in summer, but winter frost management remains essential:
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The raised frame and free space under the unit allow natural defrosting without direct contact with the membrane.
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If necessary (special drainage configuration), we plan a flow directed towards a traffic-free area, in order to avoid ice patches.
Commissioning: AirGreen quality control
Our commissioning protocols guarantee performance from day one:
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Nitrogen leak tests with stabilization.
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Deep vacuum controlled by micronmeter , until lasting stabilization.
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Complete electrical checks : polarity, continuities, tightening torque, disconnection tests.
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Functional tests in cold and hot conditions: intensity, evaporation/condensation temperatures, delta-T and Inverter behavior.
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User settings : explanation of modes, setpoint deviations, filter maintenance and best practices for saving energy.
Flat roof specificities and challenges: how we managed them
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Wind and wind resistance : Rooftop appliances are exposed. We mechanically secure the frame to the rails, and the distributed mass prevents any lifting.
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Routes : to avoid any risk of snagging or water pockets , the line follows a short route , without sharp bends, and remains clear of maintenance points (drains, vents).
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Membrane protection : no sharp edges in contact. Insulating pads under rails protect elastomeric or bituminous membrane roofs and facilitate possible relocation without damage.
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Winter service : Access must not depend on an unstable ladder. We define a safe path and indicate to the owner which access points must be kept free of snow.
Customer results: comfort, efficiency and peace of mind
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Four-season comfort : efficient air conditioning in summer, efficient heating support in spring and autumn, or even in the middle of winter depending on the model's temperature range.
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Measurable reduction in consumption thanks to the inverter compressor and optimization of line lengths.
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Silence : the distance from the ground and the damping of the rails reduce the transmission of vibrations to the structure.
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Preserved aesthetics : no footprint on the ground or on the facade; from the street, the equipment remains discreet .
AirGreen Best Practices for Flat Roof Installation
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Always distribute the load (rails + high-density pads): this is the key to protecting the membrane.
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Provide air clearances greater than the minimum when the appliance is surrounded by roof elements (parapets, ducts, chimneys).
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Use UV insulators and stainless steel clamps for long-term durability.
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Systematize external disconnection and clear markers (circuit labeling) to facilitate any intervention.
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Check the condition of the pads , seals and fasteners at each maintenance visit.
Recommended HVAC maintenance
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Clean the inner head filters every 4–8 weeks during use.
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Annual inspection by our technicians: pressures, temperatures, intensities, tightening, condition of the insulation and roof passages.
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Clear the area around the condenser (leaves, objects) and check defrosting in winter.
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Never defrost the appliance mechanically : the integrated defrost cycle takes care of it.
Grants and Eligibility
Depending on the configuration and certified performance of the chosen indoor head, this type of wall-mounted heat pump may be eligible for energy efficiency programs available in Quebec. We assist our clients in verifying criteria , preparing files and optimizing the energy-efficient solution best suited to their home.
Why choose AirGreen for your flat roof installation?
We design each project as a mini-engineering project : calculation of load on the membrane, choice of rails and pads , orientation, optimal line length, service strategy and safety . Our promise: a durable, efficient and easy-to-maintain HVAC installation , delivered turnkey by a local team that understands the climatic realities of Greater Montreal.