Installation of a Sharp (ZU1 series) wall-mounted heat pump in Rosemont–La Petite-Patrie
AirGreen installs a Sharp (ZU1 series) R-32 wall-mounted heat pump on a flat roof in Rosemont–La Petite-Patrie: protected route, winter clearances, precise commissioning and HVAC maintenance advice for four-season comfort.
In summer, the outdoor unit rejects the house's heat outside.
Generic illustration of this type of installation, not a survey of this job site. Tap a number.
Mounted level on a wall plate, high enough for the air to reach the whole room, with enough space around it to slide the filters out easily.
The refrigerant lines, the communication cable and the drain go through the wall in a single opening, sealed against water, cold air and insects.
Two insulated copper pipes connect the two units. Outside, a line cover can protect them from sun, knocks and weather.
A shut-off switch near the outdoor unit isolates it safely for service. It must stay accessible at all times.
The compressor and the fan. In heating mode it captures heat from the outdoor air, even in winter, and moves it inside.
On the ground or on the wall, it keeps the unit above accumulated snow. The unit stays clear and defrost water can drain away.
The fan needs to blow freely. Storage, a fence or a wall too close, and efficiency drops while noise goes up.
A flat roof construction site, designed for Montreal winters and quiet performance
Project context and comfort objectives
At AirGreen , we were contacted by a co-owner of a plex in Rosemont–La Petite-Patrie who wanted to modernize his air conditioning system and benefit from truly efficient heating even in the coldest weather. His specifications were clear: a compact, energy-efficient, noise-reducing HVAC solution that would remain simple to maintain . We recommended a Sharp ZU1 series wall-mounted heat pump with R-32 refrigerant , coupled with a high-efficiency wall-mounted indoor head, perfect for an open-plan Montreal home.
Why the Sharp (ZU1 range) for a Montreal plex
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High efficiency in low temperature heating , adapted to the climate of Greater Montreal .
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R-32 refrigerant : better environmental profile and reduced charges compared to R-410A.
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Eco Inverter function and Plasmacluster technology (air quality and perceived comfort).
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Compact condenser format, ideal for flat roofs typical of Rosemont .
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Contained noise levels, a crucial point for preserving the peace and quiet of neighbors.
Our approach to HVAC installation on flat roofs
Choice of location and noise management
We install the condenser on an aluminum structure placed on supports adapted to the flat roof, with anti-vibration pads . The equipment is away from the parapet and chimneys in order to optimize air release and avoid any blowing recycling , a frequent cause of capacity losses and increased noise. The chosen orientation protects the fan from prevailing winds in winter and facilitates defrosting.
Roof waterproofing protection
Each support point is distributed over membrane-compatible soles (TPO/EPDM/elastomer). No structural perforation of the roof is made: the passage of refrigeration connections and the electrical cable is done via a technical chimney sealed with sleeves and roof-approved sealants.
Refrigeration path and wiring
The insulated refrigeration lines run in a black UV conduit installed on a cable tray; they join the shortest interior column. We maintain a bend radius that is respectful of the copper to protect the compressor. The communication cable and the power supply are physically separated from the power circuit to avoid interference and comply with the Quebec electrical code.
Condensate management
The external station discharges practically no water in summer on this type of installation. Inside, we favor a gravity drain to an existing return point; in the absence of a sufficient slope, we provide a soundproofed mini-condensate pump with a safety float (cut-off in the event of overflow).
Commissioning and checks
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Nitrogen leak test then deep vacuum (< 500 microns) with digital recorder.
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R-32 charge supplement to the nearest gram depending on the exact length of the connections.
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Control of intensities and measurement of supply/return temperatures to validate the expected SEER/HSPF.
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Setting of cold/heat/auto modes , adjustment of shutters for distribution in living rooms.
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Explaining HVAC maintenance routines to the customer (filters, defrosting, clearing units).
Salient visual details of the construction site
Support and stability
The photo clearly shows our raised aluminum frame , ensuring optimal clearance under the unit for frost and snow . This height also limits the suction of dust from the roof and extends the lifespan.
Lines and finishes
The insulated bundle follows a clean path, protected by an external duct ; the junctions are capped to withstand freeze/thaw cycles. The result: a clean installation, accessible to technicians for maintenance and aesthetically pleasing for the co-ownership.
Multi-unit management
The site has other condensers in a row. We therefore respect minimum distances between devices (blowing/suction) in order to avoid thermal interference and maintain nominal efficiencies .
Results obtained: comfort, silence and savings
Upon commissioning, the customer observes:
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Even air conditioning in the main room, even on a sunny evening.
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Stable heating without over-using the auxiliary electric baseboards.
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Very low perceived noise inside; on the roof, only a moderate hiss at auto speed.
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Controlled consumption thanks to the inverter which continuously adapts the power.
Operating tips to maximize longevity
Daily good practices
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Maintain a clearance of at least 30–40 cm around the outdoor unit and ensure natural de-icing.
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Clean the wall head filters every 4–6 weeks during use.
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Avoid setting the temperature too low in summer (22–23°C is sufficient) and too high in winter; the inverter works better at partial load.
Annual preventive maintenance
We recommend a complete HVAC maintenance before winter: checking pressure switches , checking condensate drainage , tightening electrical terminals , inspecting line insulation and updating settings if necessary. Regular maintenance protects the manufacturer's warranty .
Technical points we monitor on flat roofs
Defrosting and wind
During defrosting , the unit briefly reverses its cycle; therefore, free flow of melted water is required. Wind deflectors are considered if the site is very exposed.
Refrigeration loads and lengths
The equivalent length of the lines influences the R-32 charge and the effective power . We calculate the additional charge per meter and balance it by electronic weighing, which preserves seasonal efficiency .
Electricity and safety
Dedicated circuit breaker, compliant cable section , accessible exterior disconnect ; all our connections follow the Quebec Construction Code . Connections are identified to facilitate future interventions.
Quick FAQs
Is a heat pump sufficient for heating in Montreal?
Yes, in well-insulated homes, the Sharp (ZU1 range) covers most needs. For extreme cold spells , we integrate backup logic (baseboards or other source) to ensure 100% comfort.
What about subsidies ?
High-efficiency R-32 wall-mounted heat pumps are generally eligible for provincial/municipal assistance when the operating efficiency and temperatures meet the current criteria. We verify the eligibility of your address and model before starting work and we support the application .
What is the point of R-32 ?
It allows for better volumetric efficiency , lower loads and a reduced GWP (global warming potential) compared to R-410A. The result: optimized performance and environmental impact.
Mistakes to avoid when installing on a flat roof
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Underestimate the clearances around the condenser: air recycling and capacity losses.
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Pierce the membrane without waterproofing detail: costly infiltration.
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Too long refrigeration journey without load recalculation: drop in COP and premature wear.
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Ignoring wind orientation : more frequent defrost cycles and increased noise.
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Forgetting accessibility for maintenance: filters never cleaned = overconsumption.
AirGreen deadlines, coordination and guarantees
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Technical visit and validation of structure/roof.
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Typical one-day installation (one head), including full testing.
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Documentation provided to the customer: serial numbers, vacuum packing records, photos, usage instructions.
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Manufacturer parts warranty + AirGreen labor warranty depending on the package selected.
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Assistance for aid programs available in Montreal , Laval , Longueuil , North Shore and South Shore .
In summary
This project in Rosemont–La Petite-Patrie illustrates what we strive to deliver: a clean, sustainable HVAC system calibrated for the Quebec climate. The Sharp wall-mounted heat pump (ZU1 series) combines efficiency, silence, and air quality. Add thoughtful installation on a flat roof, careful waterproofing, and meticulous commissioning , and you get four-season comfort with low operating costs.
Are you planning a similar project in Montreal , Laval , Longueuil , on the North Shore or South Shore ? Our technical team will guide you from the choice of model to the grants , with a single objective: an impeccable result, from day one.
How it goes, from the first call to the end
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
Model, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
Floors and furniture protected, wall plate position marked level, wall opening located.
A single opening, with the slope the drain needs to flow outside.
Set on a stand raised above the snow, with the clearances the manufacturer requires.
Connected, insulated and protected. The opening is then sealed against water, cold air and insects.
A dedicated circuit and an accessible disconnect near the outdoor unit.
Leak test, vacuum, then start-up and a check of heating and cooling.
Remote, modes, filters: we show you the essentials before we leave.
- The on-site estimateWe look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
- The quoteModel, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
- Getting readyFloors and furniture protected, wall plate position marked level, wall opening located.
- The wall openingA single opening, with the slope the drain needs to flow outside.
- The outdoor unitSet on a stand raised above the snow, with the clearances the manufacturer requires.
- Lines, cable and drainConnected, insulated and protected. The opening is then sealed against water, cold air and insects.
- The electrical workA dedicated circuit and an accessible disconnect near the outdoor unit.
- Tests and start-upLeak test, vacuum, then start-up and a check of heating and cooling.
- The walkthroughRemote, modes, filters: we show you the essentials before we leave.
What the unit delivers when it is cold
The range as published on airgreen.ca: pick a size to see its capacity in deep cold.
| Size | Heating at −8 °C | Heating at −15 °C | Coldest certified point | COP at −15 °C | SEER | HSPF | Indicative LogisVert aid |
|---|---|---|---|---|---|---|---|
| Sharp ZU1 12 000 | 14,500 | 12,000 | −27 °C: 7,200 | 2.11 | 22.0 | 11.0 | $1,740 |
| Sharp ZU1 15 000 | 18,100 | 15,300 | −27 °C: 10,100 | 2.1 | 24.0 | 11.0 | $2,172 |
| Sharp ZU1 18 000 | 22,000 | 18,000 | −27 °C: 11,500 | 2.2 | 24.0 | 11.0 | $2,640 |
| Sharp ZU1 24 000 | 22,400 | 19,000 | −27 °C: 12,300 | 2.2 | 22.0 | 11.0 | $2,688 |
According to NEEP, it delivers 14,500 BTU/h at −8 °C (17 °F), more than at 8 °C (14,000 BTU/h). It heats as hard in moderate cold as in mild weather.
According to NEEP, its certified maximum capacity at −27 °C (−17 °F) is 7,200 BTU/h, 60% of its nominal 12,000 BTU size.
At 8 °C, its certified maximum capacity reaches 17,100 BTU/h, 42% more than its nominal 12,000 BTU size.
According to NEEP, it delivers 18,100 BTU/h at −8 °C (17 °F), more than at 8 °C (18,000 BTU/h). It heats as hard in moderate cold as in mild weather.
According to NEEP, its certified maximum capacity at −27 °C (−17 °F) is 10,100 BTU/h, 67% of its nominal 15,000 BTU size.
At 8 °C, its certified maximum capacity reaches 21,800 BTU/h, 45% more than its nominal 15,000 BTU size.
According to NEEP, it delivers 22,000 BTU/h at −8 °C (17 °F), more than at 8 °C (21,600 BTU/h). It heats as hard in moderate cold as in mild weather.
According to NEEP, its COP at −27 °C is 1.88: the highest of the ZU1 line, which ranges from 1.79 to 1.82 at that temperature.
According to NEEP, its certified maximum capacity at −27 °C (−17 °F) is 11,500 BTU/h, 64% of its nominal 18,000 BTU size.
At −27 °C, its certified minimum capacity is 3,200 BTU/h (5,500 at 8 °C). It slows down instead of cycling on and off.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 19,000 BTU/h, 79% of its nominal 24,000 BTU size. Its COP there is 2.20.
Data read live from the airgreen.ca page of each size (NEEP / AHRI certified performance). When the title names the installed size, it is highlighted; otherwise the whole range is shown. The aid shown is today’s, using Hydro-Québec’s rule ($120 per 1,000 BTU/h at −8 °C); amounts quoted in the article date from its publication. Only Hydro-Québec confirms the assistance granted.
And at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
Baseboards and electric furnaces turn 1 kWh of electricity into 1 kWh of heat. A heat pump delivers more: that is its COP. At Hydro-Québec’s rate D (11.142¢/kWh above 40 kWh a day, since 1 April 2026):
Hydro-Québec: a heat pump can be up to three times more efficient than baseboards for heating in the colder months.
Estimate per kWh of heat, at the chosen temperature, using the certified COP from the product page. Taxes, access charge and backup heat not included.
Conversion: 1 W = 3.412 BTU/h. An indication, not a load calculation: baseboards and furnaces are often stronger than the real need, and they can stay as backup. AirGreen confirms the capacity on site.
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Clean the indoor unit's filters.
- Clear leaves and debris left on the outdoor unit by winter.
- Test cooling before the first hot days.
- Clean the filters more often when the unit runs a lot.
- Keep plants away from the outdoor unit.
- Check that no water drips from the indoor unit.
- Rake the leaves around the outdoor unit.
- Test heating before the first cold days.
- Book periodic maintenance before winter.
- Keep snow away from the stand and the front of the unit.
- Let the unit defrost: it is normal.
- Never hit the ice on the fins; call us if the unit stays iced up.
Which type of equipment for your project?
Pick what looks like your need.
Four mistakes we do not make
Flip each card to see what we do instead.
What people ask us about this kind of work
Does a wall-mounted heat pump heat in winter?
Wall-mounted or multi-zone: how do I choose?
Where does the outdoor unit go?
Are there grants?
Do I need a permit?
How cold can it heat?
How much can I save?
How is the LogisVert assistance calculated?
Is it noisy?
The outdoor unit is covered in ice: is that normal?
Does AirGreen hold the required licences?
Is the estimate free?
No question matches. Write to us: we answer.
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Text and photo: a real AirGreen Climatisation & Chauffage job. The diagrams are generic illustrations of the type of installation, not a survey of this job site. Sources of the added figures: airgreen.ca product pages (NEEP / AHRI performance), Hydro-Québec (Heat pumps page, LogisVert, read on 13 October 2026), Régie de l’énergie (rate D as of 1 April 2026).