Installation of a Sharp (ZU1 range) wall-mounted heat pump in Rosemont–La Petite-Patrie

A flat roof installation designed for snow, wind and longevity

At AirGreen , we have just completed the installation of a Sharp wall-mounted heat pump – ZU1 series on a typical plex in Rosemont–La Petite-Patrie . The outdoor condenser is installed on the flat roof , on a raised pedestal designed to withstand Montreal winters : snowdrifts, gusts and freeze/thaw cycles. This project illustrates our approach to a demanding HVAC installation on a membrane roof building, combining performance , durability and respect for the co-ownership .

Why a Sharp (ZU1 range) for a Rosemont plex?

The Sharp ZU1 range is a new generation wall-mounted heat pump using R-32 refrigerant , recognized for:

• high seasonal efficiency in heating and air conditioning;

• reliable operation in extreme cold (optimized defrosting for our winters);

• controlled acoustics , appreciable in dense environments;

• Plasmacluster Ion technology, which contributes to healthier indoor air .

In a plex dwelling, the ZU1 wall-mounted head + condenser assembly efficiently covers the main living area (living room, dining room, open kitchen), while maintaining measured electricity consumption .

Built context: flat roof, access via hatch and membranes to be protected

The building has a membrane roof with access through a hatch . In this context, our priorities are:

• protect the envelope (no uncontrolled perforation of the membrane);

• control point loads on the roof insulation;

• ensure surface drainage in summer and mid-season;

• secure the device against blown snow and snowdrifts.

We chose a raised structure which:

• clears the underside of the unit by 18 to 24 inches to prevent burial in the event of a storm;

• distributes the load on roof-compatible distribution pads (without perforating the membrane);

• leaves the water free to flow to the drains.

Exterior Installation Details: Stability, Drainage, and Service

• Aluminum/galvanized steel pedestal : resistant to corrosion and freeze/thaw cycles; silent blocks to reduce vibration transmission to the structure.

• Orientation of the condenser in the dominant axis of the site winds to limit recirculation and promote defrosting .

• Rear and side clearance respected for air intake and extraction ; service space maintained for maintenance (pressure gauges, fin cleaning).

• Summer condensate management : controlled flow on the roof surface, away from membrane upstands; no stalactites at the roof edge.

• Shortest possible refrigeration path between the drilling and the unit, with continuous insulation to prevent condensation and losses.

• UV protection of weather-resistant ducts and attachments; caps and butyl tape at entry areas to maintain watertightness.

Crossing the envelope: sealing and fire protection

At the right of the opening (wall outlet to roof):

• installation of a sleeve to protect the insulation;

• membrane compatible sealant and clean finish on the exterior side;

• airtight seal on the interior side to block any moisture infiltration;

• compliance with fire requirements when the crossing touches a required separation.

These points prevent infiltration , moisture bridges and premature deterioration of materials.

Electrical connections and grounding

• Dedicated circuit with appropriate circuit breaker ;

• disconnection box accessible on the roof, positioned away from runoff;

• compliant equipotential bonding and earthing ;

• UV-resistant cabling and stainless steel fasteners for cold resistance.

Interior: high wall head, regular diffusion and gravity drain

Inside, the wall-mounted head is placed high in the living room, with clearances respected around the shutters. We have favored a gravity drain (when the layout allows it) for maximum reliability and silence ; otherwise, our teams provide a pump with an anti-siphon loop and simplified maintenance . The hooded finishes harmonize with the decor, while remaining accessible for filter maintenance.

What snow changes… and how we anticipate it

Installing on a flat roof in the middle of winter requires specific choices:

• Significant elevation : the air intake and the battery must remain clear of blown snow.

• No closed cavities around the device: we avoid creating snowdrift traps.

• Short refrigeration path to reduce losses and defrosting times .

• Checking defrosting during commissioning and instructions to the customer on automatic defrosting mode (normal phenomenon in very cold weather).

Result: the unit breathes , defrosts properly and maintains heating capacity , even after a storm.

Commissioning: rigorous check before handing over to the customer

We systematically proceed to:

• a deep vacuum (vacuum resistance control);

• a pressure/temperature check according to the outside temperature of the day;

• a complete electrical test (intensities, tightenings);

• calibration of scanning and instructions;

• customer training : filters, modes, gentle cleaning of fins, best practices in periods of intense cold.

Concrete benefits for the owner

• Stable comfort in the open area (efficient supplementary heating and uniform air conditioning);

• Healthier indoor air thanks to Plasmacluster ;

• Silence inside and out;

• Controlled consumption thanks to the inverter and careful insulation of the lines;

• Easy maintenance : clear access to the condenser and filters.

Grants and support

The performance of the ZU1 range opens access to assistance programs in effect in Quebec for efficient heat pumps . We support our customers in Montreal , Laval , Longueuil , on the North Shore and the South Shore : validation of eligibility, advice on related sealing and caulking , preparation of documents.

AirGreen Best Practices for a Flat Roof Heat Pump

1. Elevate the condenser at least 18–24 in. above the expected snow plane.

2. Move the appliance away from the risers and drains to allow free drainage.

3. Distribute the load with membrane-compatible pads ; avoid piercing the cover.

4. Take care with the continuous insulation of the refrigeration lines (no breaks when passing through the roof).

5. Limit link lengths to preserve capacity and efficiency.

6. Provide service access (secure path, clear hatch) for annual maintenance.

7. Inform the customer: normal defrosting in winter, keep the unit clear , do not store objects against the pedestal.

Recommended HVAC maintenance

• Cleaning the head filters every 4–6 weeks during intensive periods.

• Annual inspection : exchangers, fans, electrical tightening, operating test.

• Gentle rinsing of the condenser fins at the start of the hot season.

• Checking the tightness of the structure fixings after the first winter.

Why AirGreen?

• Proven HVAC expertise on plexes and condos in Greater Montreal;

• Installation method suitable for flat roofs and membranes ;

• Complete support : sizing, implementation, installation, commissioning , HVAC maintenance and grant procedures ;

• Clean finishes and documentation provided to the customer for trouble-free operation.

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Are you looking for a similar project in Rosemont–La Petite-Patrie , Montreal , Laval , Longueuil , on the North Shore or the South Shore ? Our technical advisors will study your building and recommend the most suitable wall-mounted heat pump , with a robust and durable flat roof installation .