A perfectly managed flat roof construction site: cold performance, silence and careful finishing by AirGreen
In the brick plexes of Rosemont–La Petite-Patrie , thermal comfort often depends on compact yet robust HVAC solutions. Here, we present a Sharp ZU1 wall-mounted heat pump installation on a typical flat roof in the neighborhood. Our client wanted an efficient system for supplemental heating in winter, very discreet for air conditioning in summer, and, above all, a durable installation that respects the integrity of the roof membrane. We meet these requirements with a combination of meticulous engineering, increased safety, and impeccable aesthetics.
Building context and client expectations
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2-story brick plex, multi-layer roof with gravel.
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Technical access via rear ladder; limited clearances around vents.
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Priorities: cold efficiency , low noise level, simple HVAC maintenance , clean wiring and no water infiltration.
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Short implementation window despite rainy weather.
Why the Sharp ZU1 responds to Montreal's climate
A compact heat pump that really heats in very cold weather
The Sharp ZU1 range (new generation refrigerant, high seasonal efficiency) stands out for its stable power when the mercury drops. It is ideal for urban housing that seeks savings without sacrificing comfort. The fine modulation of the inverter compressor reduces on/off cycles, improves its lifespan, and maintains a constant indoor temperature.
Qualities appreciated by our teams and our customers
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Efficient heating down to the low ambient temperatures typical of Montreal.
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Quiet operation on both sides (indoor unit and condenser).
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Easy filter cleaning and air purification options useful in urban environments.
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Optimized consumption in air conditioning mode during the heat waves of July/August.
Our flat roof HVAC installation methodology
Choice of positioning: safety, air circulation and longevity
We placed the condenser on a raised aluminum support fixed on sole plates placed on distribution joists. This riser offers:
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a free passage for the flow of rainwater and thaw water;
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a reduction in vibrations transmitted to the structure;
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a guard above the snow accumulation.
Clearances to obstacles (vent caps, parapets, stumps) are respected to ensure air intake and discharge, as well as safety during maintenance.
Membrane protection: zero compromise
The roof membrane is protected by footings covered with durable insulation and compatible separation strips. Penetrations are limited to the bare minimum; all openings pass through an existing service chimney with roof-grade flashing and sealant. The result: no aggressive point loads and a durable waterproof seal.
Refrigerated and electrical route: clean and rational
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Insulated refrigeration lines , under UV sheath, directed horizontally to the edge of the roof then towards the rear facade.
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Optimized total length (≈ 12–15 m) to preserve efficiency.
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CSA approved disconnect box and electric whip, installed within service range with clear markings.
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Grounding and dedicated circuit breaker in accordance with the current Code.
Condensate management: effective in all seasons
In air conditioning, the condensate from the indoor unit is drained by gravity with an appropriate air seal. In winter de-icing mode, the water flows onto the roof towards the drain, preventing icicles from forming on the facade.
Finishing and acoustics
We attach anti-vibration pads under the support and precisely wedge the condenser's position. This limits noise transmission to the rooms on the top floor and maintains a very low noise level for neighbors.
Inside: discreet integration of a wall unit
Head position: comfort and aesthetics
The interior headboard is installed high on the living room wall, well clear of the curtains. This positioning ensures:
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even distribution of air, without direct drafts on the sofa;
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reliable probe reading for precise control;
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clear access for HVAC maintenance (filters, exchanger).
Drilling and capping
The 65mm hole is made with a slight outward slope. The connections are capped with matching white capping, ensuring a clean finish in the room. On the outside, the UV cap follows the drain angle to prevent water retention.
Commissioning and performance checks
Key steps carried out by our technicians
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Nitrogen test and pressure leak test.
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High vacuum (500 microns) and stabilization.
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Checking currents and voltages, fan rotation direction, and card-to-card communication.
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Control of supply/return temperatures in cooling and heating modes.
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Fine programming: target temperature, auto speed, night mode, automatic restart.
Result at the customer
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Stable temperature in the apartment and immediate reduction of perceived humidity in summer.
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Outside noise almost imperceptible from the backyard.
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Controlled electricity consumption thanks to the optimization of the heating curve.
What this project illustrates about our know-how
Mastering Montreal flat roofs
Rosemont's gravel roofs require suitable supports , precise clearance management and careful handling of penetrations. We secure the membrane, reduce vibrations and facilitate future interventions (de-icing, cleaning, inspections).
“AirGreen” finish
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Sheathed wiring and aligned capping .
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Clear labeling of circuits and components.
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Commissioning documentation provided to the customer, with advice on use in winter and heat waves.
Practical advice for plex occupants in Montreal
Use and savings
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Keep the setpoint stable (e.g. 22–23°C) instead of changing it frequently; the inverter is more efficient this way.
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Clean the filters every 4 to 6 weeks during the season; a clean filter protects the exchanger and reduces the bill.
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In winter, leave clearance around the condenser after snowfall; avoid snow drifts that block the suction.
Annual maintenance recommended
A complete HVAC maintenance service (electrical inspection, heat exchanger cleaning, condensate verification, functional checks) extends the lifespan and maintains efficiency. We schedule these visits before peak periods (spring/fall) to minimize any disruption to comfort.
Possible grants and eligibilities
Recent high-efficiency wall-mounted heat pumps , such as the Sharp ZU1 , are generally eligible for the main programs offered in Quebec for improving energy efficiency, depending on the housing configuration and certified performance. We support our customers in Montreal, Laval, Longueuil, North Shore and South Shore in preparing the required files, proof of installation and documents.
Why choose AirGreen for your HVAC installation?
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Land expertise on plexes , condos and suburban houses in Greater Montreal.
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Teams trained in working at height safety, roof waterproofing practices and advanced commissioning procedures.
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Responsive after-sales service , parts and technical support available locally.
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Clear advice on HVAC usage, subsidies and maintenance for lasting comfort.
Next step
Are you looking for a high-performance, discreet heat pump for a complex in Rosemont , Villeray , Mercier–HoMa , or elsewhere in the region? We evaluate the best connection route, support height, and clearances on site, then provide a detailed and transparent quote.
Technical sheet – highlights of this pose
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Machine type: single-zone wall-mounted heat pump .
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Brand / range: Sharp ZU1 .
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Installation: condenser on raised support with anti-vibration pads, on bases placed on a flat roof.
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Route: UV insulated refrigeration lines; ~12–15 m optimized; clean capping on the rear facade.
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Electricity: dedicated circuit breaker, disconnect box within reach, ducted wiring.
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Condensates: gravity drainage and de-icing management towards roof drain.
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Finishing: standard clearances, sealing of crossings, easy HVAC maintenance .
At AirGreen, we combine technical precision and respect for Montreal's buildings to deliver installations that last, summer and winter.