Context: a typical Plateau plex with flat roof and access by external staircase
In the heart of Plateau-Mont-Royal , we are working on a brick plex with a gravelled flat roof and peripheral parapets . The owner wants to modernize the comfort of the accommodations, limit the clutter on the facade and reduce the noise perceived in the backyard. We are proposing a Zephyr wall-mounted heat pump in an outdoor unit configuration on the roof to free up the rear walls, secure clearances, facilitate maintenance and preserve the heritage aesthetic of the neighborhood.
Why a Zephyr mural for this building?
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Installation flexibility : Zephyr outdoor units are well suited to rooftop installations thanks to their low weight and easy-to-respect clearances.
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Efficiency in mid-season and summer : fine modulation of the compressor to stabilize the temperature in through-housing where sunlight varies greatly.
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Controlled noise level : useful in an urban environment where the proximity of neighbors requires discreet installations.
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Compatibility with local requirements : recent devices that can meet the efficiency criteria associated with the assistance programs applicable in Greater Montreal (to be confirmed according to the capacity and series chosen).
Installation details: a pose designed to last
Support and protection of the membrane
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Aluminum frame on adjustable brackets placed on treated wood joists serving as distribution pads : this configuration distributes the load on the gravel and preserves the bituminous/TPO membrane.
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Protective mat under the joists (white walking area) to prevent any abrasion caused by vibrations and movement during maintenance.
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Silent blocks under the chassis base to filter structural vibrations and maintain low internal structure-borne noise .
Refrigeration and electrical routing
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Short, straight route to the rear technical column: the refrigeration connections are continuously insulated and covered at the unit outlet for UV protection.
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Outdoor disconnect box and power cable in weatherproof rigid sheath, stainless steel fixings: compliance and safety.
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Brazing under nitrogen , deep vacuum and electronic leak testing before opening the valves: reliability of the assemblies and longevity of the circuit.
Condensate and defrost management
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In air conditioning mode, the evacuation is carried out by gravity towards a collection point on the roof, with a continuous slope and insulation of the drain to avoid external condensation.
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In heating mode, the unit remains clear of snow thanks to the raised chassis; we recommend a snow guard and a free discharge area on the front of the unit to prevent recirculation of cold air during defrost cycles.
Clearances and air circulation
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Respect the lateral and rear clearances in relation to the parapet in order to ensure air intake and blowing without recirculation.
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Orientation studied to limit the impact of prevailing winds and gusts above the roofs of the Plateau.
Sizing: capacity and sound levels suitable for a plex
After taking measurements (surface area, ceiling height, exposure, infiltration), we retain a range of 9,000 to 12,000 BTU/h for the main living area of a home. This capacity:
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guarantees low-load modulation for cool evenings in May and September;
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allows effective dehumidification during hot spells;
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maintains a noise level harmonized with the requirements of a dense neighborhood.
AirGreen commissioning: checks that make the difference
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Nitrogen pressurization and pressure gauge verification.
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High vacuum up to the recommended threshold to extract moisture and non-condensables.
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Valve opening and stabilization; superheat/subcooling control.
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Electrical validation : intensity, grounding, emergency stop.
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Reading of the supply/return temperatures in the accommodation; adjustment of the setpoints.
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Customer training : usage advice, basic maintenance, reminder of maintenance intervals.
Results obtained on this site
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Immediate heat reduction in late afternoon in south-facing rooms.
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Low exterior noise in courtyards and balconies thanks to the rooftop installation.
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No aesthetic damage to the rear facades: a sensitive point in the Plateau-Mont-Royal .
HVAC Maintenance: Ensuring Performance Season After Season
Regular HVAC maintenance ensures performance and lifespan:
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Gentle cleaning of the external battery in spring to remove dust and pollen deposited by the wind.
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Annual inspection of the chassis fixings, the condition of the pads and the membrane under support.
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Checking electrical tightening, pressures and characteristic temperatures.
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Rinse the inner head filters every 4 to 6 weeks during peak periods.
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Control of the slope of the drain and insulation exposed to UV.
Common pitfalls when installing on flat roofs and how to avoid them
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Direct support on gravel/membrane : risk of premature wear; we install pads and protective mats .
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Air recirculation against the parapet: we keep clearances and direct the blowing in the free axis of the roof.
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Uninsulated drainage : runoff on ceilings in summer; we insulate and secure the slopes.
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Refrigeration connections too long : pressure losses and reduced efficiency; we optimize the route via the technical column.
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No winter plan : frost and snow; we raise the aircraft and provide snow guards if necessary.
Grants and administrative support
Recent and efficient wall-mounted heat pumps may be eligible for assistance programs depending on their capacity , efficiency and operating range . We will validate eligibility with you and prepare the required parts for Montreal, Laval, Longueuil, North Shore and South Shore .
Tips for maximizing savings
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Maintain a stable setpoint (in summer ~24°C, in mid-season ~21–22°C).
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Use modulation rather than sudden variations.
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Leave interior doors open to allow circulation.
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Avoid turning off the power at the circuit breaker in winter to allow for defrost cycles.
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Schedule annual maintenance before peak demand periods.
Why entrust your HVAC installation to AirGreen?
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Flat roof expertise : proven support methods, membrane protection and secure access.
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Installation quality : brazing under nitrogen, deep vacuum, documented controls.
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Responsive after-sales service : parts available and rapid interventions throughout Greater Montreal .
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Advisory approach : choice of wall-mounted heat pump adapted to the surface area, noise and heritage constraints specific to the Plateau-Mont-Royal .
Conclusion
This installation of a Zephyr wall-mounted heat pump on a flat roof in Plateau-Mont-Royal illustrates our approach: careful support , membrane protection , clean routing , rigorous commissioning and planned HVAC maintenance . The result: summer comfort and reliable heating support , with minimal noise and a preserved façade—exactly what plex owners in Greater Montreal are looking for.