Two outdoor units on the roof terrace: performance, silence and exemplary finish
At AirGreen , we have just completed a particularly meticulous HVAC installation in Nuns' Island . The project consisted of installing two Sharp wall-mounted heat pumps (ZU1 range, R-32 refrigerant) dedicated to two separate zones of a modern condominium. Our client wanted stable comfort in summer and winter , reduced outside noise , and aesthetic integration on a roof terrace covered with an elastomeric membrane.
From the design stage, we have favoured a sustainable approach: raised aluminium supports , navy blue anti-vibration pads under the plates, standard clearances for air supply and return, and a short refrigeration path to optimise seasonal yields.
Client context and needs
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Type of accommodation: contemporary condo with concrete structure, light-colored coated facade, access to a private terrace.
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Objectives: efficient air conditioning during summer peaks, efficient heating in very cold weather without noise overload for the neighborhood, and harmonious coexistence of two outdoor units.
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Constraints: accessible roof with black membrane, vibration management to prevent any structural transmission, wall crossings near a French window, and easy maintenance .
Why the Sharp wall-mounted heat pump (ZU1 range)
Sharp's ZU1 range is one of the latest models using R-32 refrigerant , favoured for its high efficiency and lower climate impact compared to the previous generation. Key advantages:
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Fine modulation inverter technology : reduced consumption and very stable interior temperature.
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Good cold resistance (reliable heating in our latitudes).
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Quiet operation : fan and compressor optimized to limit noise levels.
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Advanced filtration inside, with Sharp's own Plasmacluster technology.
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Eligibility for grant programs when efficiency criteria are met — a point that our team systematically verifies for our clients in Greater Montreal.
Helpful note: When two separate zones need to be managed independently (bedroom/office, living room/guest room, etc.), two single-zone units can provide remarkable flexibility and reliability , while avoiding lengthy internal distributions.
Rooftop terrace layout details
We install the two condensers in line , parallel to the wall, on mechanically anchored aluminum trestles . Each plate rests on a shock-absorbing mat which:
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decouples the vibration,
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protects the membrane,
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stabilizes the charge during defrost cycles in winter.
This raised configuration has several benefits:
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Snow clearance during winter, preventing the grids from getting blocked.
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Simplified drainage of meltwater and rainwater.
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Easy maintenance , with full access to service panels.
Respect for clearances and air circulation
Sharp units blow through side and front grilles; we have maintained an air corridor between the two so that air discharged from one does not feed the other . The positioning takes into account:
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prevailing winds on the river, frequent on Île-des-Sœurs,
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solar reverberation on black membrane (which can increase the ambient temperature around the machines in summer),
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minimum distances recommended by the manufacturer and required by code.
Refrigeration path and power supply
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Reduced refrigeration lengths thanks to a direct wall crossing behind each machine.
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Controlled bending and nitrogen brazing to ensure watertightness.
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Continuous insulation of the linesets to prevent condensation and losses.
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Communication cables and dedicated power supply from the housing electrical panel, protected by suitable circuit breakers .
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Discreet white capping along the wall for a clean, UV-resistant finish.
Condensate management
Inside, we have favored gravity drainage when the slopes allow it. If the configuration requires it, we integrate a silent lifting pump with an anti-overflow alarm . In this project, the available heights allow gravity drainage , simplifying maintenance and reducing the risk of breakdown.
Noise reduction and acoustic comfort
Nuns' Island is a residential area where tranquility is valued. To limit noise perception:
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Anti-vibration pads under each of the plates,
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Tightening of fasteners to the correct torque to avoid harmonics,
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Night mode programmed on thermostats to reduce ventilation speed during sensitive periods,
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Measured spacing between units to avoid any airflow interference .
Result: a very low exterior noise level , imperceptible from inside when the French windows are closed.
Commissioning and checks
Our certified technicians carry out the following steps:
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Deep vacuum and leak testing,
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Fluid opening , balancing and control of over/underheating ,
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Electrical verification and communication between cards,
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Calibration of remote controls and instructions,
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Customer training : best practices for use, preventive HVAC maintenance , filter management and seasonal modes.
Results obtained
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Rapid temperature rise in heating mode, even in cold winds on the river,
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Uniform comfort in targeted rooms,
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Lower consumption compared to the old portable solution + additional heaters,
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Impeccable aesthetics from the terrace, without visible cables or overhangs.
Operating advice for Greater Montreal
For residents of Montreal, Laval, Longueuil, North Shore and South Shore , we recommend:
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Auto/modulation modes : let the heat pump modulate rather than alternating on/off.
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Stable set temperature : avoid variations of more than 2°C to maximize efficiency.
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Winter clearance : maintain 30 to 60 cm free around the units; remove snow gently without hitting the grilles.
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Annual maintenance : cleaning of internal filters, inspection of connections, checking of supports and service caps.
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Summer protection : if the sunlight is very direct, consider a non-obstructive sunshade to limit surface overheating on the membrane.
Grants and Compliance
Sharp's ZU1 series R-32 wall-mounted heat pumps achieve seasonal performance ratings that can meet the criteria of grant programs offered in Quebec (depending on BTU configuration and certified performance). Our team supports each customer in:
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check eligibility (power, performance, installation by qualified contractor),
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assemble the supporting documents ,
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and submit the files within the required timeframes.
Why choose AirGreen?
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HVAC specialists in Greater Montreal, we are experts in urban (rooftop terraces, condominiums, plexes) and residential (houses, intergenerational) contexts.
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Selection of proven equipment : Sharp, Gree, Fujitsu, Midea… exclusively in their recent R-32 / R-454B versions .
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High-level finishing : alignment of supports, cappings in coordinated colors, watertight drilling and clean management of the membrane .
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After-sales service : scheduled maintenance, parts available, priority assistance during cold weather.
AirGreen operates daily in Montreal , Laval , Longueuil , on the North Shore and the South Shore for wall-mounted heat pump , wall-mounted air conditioner , multi-zone systems and central heat pump projects. For a detailed quote and a perfectly sized choice of BTU capacity, our technical team guides you from the thermal study to commissioning.