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Installation d’une Sharp ZU1 thermopompe murale à Montréal (Rosemont–La Petite-Patrie)
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Installation of a Sharp ZU1 wall-mounted heat pump in Montreal (Rosemont–La Petite-Patrie)

A winter HVAC installation on a flat roof: stability, efficiency and silence, even in extreme cold

In the heart of Rosemont–La Petite-Patrie , we installed a Sharp ZU1 wall-mounted heat pump on the flat roof of a residential building. Carried out at night during heavy snowfall , this project demonstrates our expertise in HVAC installations in an urban Montreal context: limited access, prevailing winds, snow accumulation, and proximity to other technical equipment.

Building context and client objectives

The building is a typical Montreal plex, surrounded by mature trees and lit residential streets. The owners wanted:

  • efficient heating in winter and discreet cooling in summer;

  • an energy-efficient solution eligible for subsidies ;

  • a silent installation, placed on the flat roof to preserve the aesthetics of the facades;

  • secure access for annual HVAC maintenance .

The Sharp ZU1 meets these requirements thanks to its Eco Inverter technology and the use of R-32 refrigerant , recognized for its better environmental performance compared to older generations.

The Sharp ZU1 in brief: controlled efficiency for the Montreal climate

The ZU1 series has been designed to maintain stable performance down to -25°C , a crucial threshold for Montreal and its prolonged cold spells. Its major advantages:

  • Inverter compressor : fine modulation of power, constant comfort and reduced consumption.

  • R-32 : more efficient refrigerant, making it easier to achieve high SEER/HSPF and opening the door to assistance programs .

  • Careful acoustics : low noise level in night mode, ideal for roofs close to bedrooms.

  • Compact format : optimized air circulation in tight technical areas.

Flat roof installation design

Installing a heat pump on a flat roof in the middle of winter requires careful planning. Our approach:

  1. Height and clearances
    The unit is raised on a galvanized steel frame fixed on anti-vibration pads . This useful height protects the unit from snow drifts and allows unobstructed defrosting . Side and rear clearances are respected to ensure airflow, including near neighboring equipment already in place.

  2. Load and sealing management
    The weight is distributed by load-bearing rails placed on shock-absorbing bases . No perforation of the membrane is carried out outside the standardized technical passages , ensuring the durability of the waterproofing .

  3. Refrigerated and electrical route
    The insulated copper lines run on continuous supports above the snow, with capping and UV insulation . The power supply joins a waterproof disconnect box , compliant with the Canadian Electrical Code, then the circuit breaker dedicated to the panel.

  4. Defrosting and melt water
    In heating mode, defrost cycles generate water. The unit is placed in a free-drip area to prevent ice stalagmites from forming near access points. The chassis level is adjusted to direct the flow away from passageways.

  5. Compatibility and coexistence of equipment
    An existing condenser shares the technical area. We have maintained buffer zones to prevent air recycling and vibration transmission between units.

Precise installation procedure

  • Pre-visit : measurements, membrane survey, identification of slopes, choice of shortest routes and safe passages to the interior premises .

  • Winter logistics : routing of equipment via secure anchor points , site lighting and markings to prevent slipping.

  • Mounting the support : assembly of the galvanized frame , level check, installation of the EPDM soles and verification of the load distribution .

  • Line installation : controlled bending, silver brazing under nitrogen, continuous insulation and frost-resistant fixings.

  • Vacuum and tests : deep vacuum, prolonged vacuum holding , weighing of refrigerant according to line length .

  • Power on : settings, heating mode tests , checking intensities and defrosted exchange surfaces .

  • Customer handover : usage instructions (auto/heating mode, ventilation), reminder of good maintenance practices .

Results: stable comfort, controlled consumption

From the moment it is put into operation, the Sharp ZU1 provides a constant hot air supply despite the sub-zero temperature. Inverter modulation prevents surges, reduces power peaks , and contributes to significant annual savings compared to on/off systems. The noise level measured on the roof remains very low, an advantage for rooms located under the roof.

Good practices and mistakes to avoid on flat roofs

To do:

  • keep ≥ 30 cm under the unit for snow/ice ;

  • provide continuous support for the lines to avoid crushing in the snow;

  • install a service box that is easily accessible and visible at night;

  • plan a snowdrift clearance in the direction of the prevailing winds.

To avoid:

  • attach the unit to a low wall or skylight (risk of air recirculation);

  • allow condensate to accumulate near an access point;

  • multiply membrane perforations beyond dedicated technical passages.

Recommended HVAC maintenance

To maintain performance:

  • interior : clean filters every 2 to 3 months ;

  • exterior : visual inspection after each heavy snowfall to clear air intakes;

  • annual : complete maintenance by our technicians (pressure switches, connections, exchanger, parameter updates).
    We offer HVAC maintenance plans tailored to Montreal, Laval, Longueuil, North Shore and South Shore with priority given to cold weather.

Grants and support

Thanks to its performance and the use of R-32 , the Sharp ZU1 may be eligible for provincial assistance programs . We support our customers to:

  • the energy pre-visit ;

  • documentation of the work;

  • the submission of supporting documents .
    This support simplifies investment and accelerates return on expenditure.

Why AirGreen for your wall-mounted heat pump in Montreal?

Our teams understand the realities of Montreal's flat roofs : membranes, slopes, snow accumulation areas, proximity to antennas and mechanical outlets. We deliver:

  • installation engineering that protects the waterproofing and the structure;

  • discreet and silent integration;

  • a turnkey service : study, HVAC installation , HVAC maintenance , usage advice and grant support.

Conclusion: a winter-ready installation, designed to last

This Sharp ZU1 wall-mounted heat pump installation in Rosemont–La Petite-Patrie demonstrates our high standards: mechanical stability , energy efficiency , and sound comfort, even in the middle of the night under the snow. The system is ready to provide reliable heating all winter and gentle cooling in the summer, with optimized operating costs year after year.

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