A flat roof, two compact condensers, a clear view of Montreal 's East End: today's project perfectly illustrates our expertise in HVAC installation in urban plexes. At AirGreen, we're modernizing the comfort of a rental building in Mercier–Hochelaga-Maisonneuve with a Sharp ZU1 wall-mounted heat pump for one unit, and upgrading the neighboring condenser belonging to another unit. The goal: four-season reliability, low noise, and optimized performance in both heat waves and extreme cold .
Why the Sharp ZU1 series for an urban plex
The Sharp ZU1 (new generation R-32 ) meets the constraints of central buildings: reduced size, high efficiency, quiet operation and low temperature performance. For occupants, this translates into:
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stable heating until the very cold thanks to the range's defrosting algorithms;
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uniform cooling without drafts thanks to fine control of the interior fan;
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significant energy savings compared to older R-410A appliances;
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eligibility for major local grants when seasonal performance criteria are met.
Building context and choice of location
Typical HoMa building with a flat roof, perimeter parapets and technical access from an interior hatch. The owners wanted:
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avoid any transmission of vibration to the housing;
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preserve the waterproofing of the bituminous coating;
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facilitate seasonal maintenance.
We therefore opted for installation on roof supports with anti-vibration pads and treated rails, leaving peripheral clearance for suction and blowing. The refrigeration path favors a vertical rise through an existing technical chimney then a gravity passage in the interior walls towards the wall head. The condensate drain from the indoor unit is recovered by gravity up to a protected waterfall; no condensate pump is necessary here, limiting noise and maintenance.
Salient technical details of the installation
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Machine type : wall-mounted heat pump (mini-split).
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Brand : Sharp .
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Range : ZU1 R-32 series (capacity adapted to the volume of the accommodation).
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Supports : rails on EPDM pads for load diffusion and vibration decoupling.
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Electricity : outdoor junction box and heating cable provided for the housing if required by winter conditions; dedicated circuit breaker for the housing panel.
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Refrigeration : insulated copper connections, nitrogen brazing , deep vacuum (≤ 500 microns) with nitrogen leak test; additional charge calculated according to the actual length.
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Roof protection : distribution mat under supports, sealing of crossings with sleeves and bitumen-compatible membranes.
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Noise : installation at a distance from the parapet to break up sound reflection; orientation of the blowing towards the free zone.
The cumulative length of the links is within a typical range for a plex (approximately 12 to 15 m), which maintains low pressure losses and high seasonal efficiency .
Construction stages and AirGreen guarantees
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Preliminary checks : structural load of the roof, condition of the covering, available routes, proximity of the electrical panel .
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Installation of supports : wedging, leveling, snow protection not required here but included in the estimate if exposed to snowdrifts.
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Drilling : minimalist core drilling with vapor barrier and sealing return ; waterproof cable glands.
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Installation of connections : careful bends, respect of curvature radii , continuous anti-UV insulation on the surface.
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Tests : nitrogen pressurization, vacuum and stabilization ; progressive start-up with superheat and subcooling control.
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Finishing : orderly paths, discreet capping at interior exits, electrical markings, roof markings.
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Delivery : explanation to the customer, HVAC maintenance schedule, registration for the manufacturer's warranty and ours on the installation.
Measured results and daily comfort
From the moment of commissioning, the indoor air temperature is stable, with remarkably low noise levels. On the roof, the perceived sound pressure level remains compatible with the coexistence of the two visible condensers: ZU1 and the neighboring unit that has been brought up to standard. The layout avoids air recirculation and allows free access to the hoods for maintenance, which speeds up interventions and reduces long-term costs.
Maintenance recommended to last in the Montreal climate
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Spring : gentle washing of the external battery, checking of the fixings and supports; checking of the clearances around the condenser (leaves, debris).
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Summer : Clean the interior filters every 4 to 6 weeks during periods of high use.
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Autumn : Inspection of the condensate drain and the crankcase heating cable if applicable.
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Winter : regular clearance in case of blown snow ; maintenance of an air corridor around the device to avoid persistent frost.
An AirGreen HVAC maintenance plan ensures consistent performance and preservation of seasonal efficiencies .
Grants and programs to consider
For a high-performance R-32 wall-mounted heat pump with efficient operation in cold weather, homeowners can check eligibility for active programs in Quebec (e.g., residential energy efficiency components). We help document the file: AHRI number, proof of professional installation, photos of serial numbers , and required forms. The Montreal , Laval , Longueuil , North Shore and South Shore areas are covered by our teams, which facilitates visits and document preparation.
Common pitfalls… and our solutions
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Devices installed directly on the membrane : risk of imprinting and punching. We use wide bases and distribution rails.
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Poorly sealed penetrations : infiltration and detachment of bitumen. We apply compatible sleeves and careful sealing return.
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Lack of clearance around the condensers**: air recirculation, frost, noise. We respect the manufacturer's clearances and orient the units to limit reflections.
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Unprotected wiring : UV, ice, breakage. We sheath and secure each section, with service loops for maintenance.
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Undersizing : short cycles, discomfort. Our load calculations take into account the envelope, solar gain, and occupancy rate.
What the occupants actually gain
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Stable comfort in living rooms in summer and winter;
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Better controlled energy bills thanks to the seasonal performance of the Sharp ZU1 ;
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Remarkable silence inside and minimal nuisance outside;
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Easy maintenance and safe access for technicians on the flat roof.
AirGreen in Greater Montreal
Our teams work daily in Montreal , Laval , Longueuil , the North Shore and the South Shore for residential and multi-unit HVAC installations . Each project benefits from a dedicated team leader , final quality control and personalized advice to maximize the durability of the equipment.
In short : This Sharp ZU1 wall-mounted heat pump installation on a roof in Mercier–Hochelaga-Maisonneuve demonstrates a clean, robust integration designed for our climate. Planning a similar upgrade for your plex or condo? We offer a quick technical assessment, a clear quote, and a timeline tailored to your needs.
Keywords : heat pump , wall-mounted air conditioner , HVAC installation , HVAC maintenance , Montreal , Laval , Longueuil , North Shore , South Shore .