Installation of a Sharp ZU1 series wall-mounted heat pump in Le Sud-Ouest
Sharp ZU1 series heat pump installed on a flat roof in the Southwest : careful HVAC installation, snow clearance, aluminum frame on skids, winter performance and 4-season comfort for Montreal and its surrounding areas.
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The job on one screen
The unit’s data sheet
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.
The article, chapter by chapter
An HVAC installation designed for Montreal winters, on flat roofs and in snowy conditions
At AirGreen , we pride ourselves on delivering robust HVAC installations that take into account the realities of Greater Montreal . This project in the Southwest borough illustrates our approach: a Sharp wall-mounted heat pump (ZU1 series, R-32 refrigerant) installed on a flat roof , with careful preparation for harsh winters and heavy snowfall.
Building context and comfort objectives
The building is a typical urban residential building with a flat roof and limited technical access. The owner wanted:
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efficient heating in very cold weather without blowing up your electricity bill;
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discreet and even cooling in summer;
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a simple integration of refrigeration connections and the power supply;
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a solution eligible for grant programs when applicable, thanks to the use of a new generation refrigerant ( R-32 ).
Why the Sharp ZU1 series as a wall-mounted heat pump?
Sharp's ZU1 series (new generation R-32 ) stands out for its stability in cold climates and its renowned Eco Inverter electronics. It is a logical choice for an urban home seeking an excellent comfort/savings ratio.
Key benefits for the customer
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Low temperature heating performance : the machine maintains a useful level of heat when the thermometer drops, ideal for Montreal, Laval , Longueuil , the North Shore and the South Shore .
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R-32 refrigerant : more efficient and with a lower GWP than R-410A, in line with regulatory developments.
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Eco Inverter technology : fine modulation, silent operation at partial load and increased durability.
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Air quality : The presence of Plasmacluster technology contributes to healthier indoor air in the service area.
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Eligibility : Depending on the capacity and low temperature performance rating, the system may be eligible for the spectrum of active Quebec incentives for recent residential heat pumps .
Visible details and technical choices of the installation
Rooftop installation: stability and durability
We installed the condenser on a raised aluminum structure fixed to treated wooden skids . This combination:
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distributes loads on the roof membrane;
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detaches the device to limit vibration transmission;
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ensures adequate clearance of the battery and fan to optimize heat exchange.
In winter, the device must breathe. So we have planned:
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sufficient elevation to reduce the risk of partial burial by blown snow;
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a clearance path around the unit to facilitate maintenance and drainage of defrost water.
Refrigeration and feeding route
The refrigeration path follows a short and clean route to the technical passage, protected by a capping adapted to the facade. We have:
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used high density closed cell insulation , sealed joints;
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added vapor barrier collars to the crossings to prevent any moisture migration;
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fixed the connections with stainless steel anchors resistant to freezing/thawing.
On the power supply side, a dedicated circuit with Code-compliant protection, a disconnect near the unit, and wiring sized for cold-weather startup current spikes complete the installation.
Condensate and defrost management
In heating mode, the heat pump performs defrost cycles. We have planned:
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an ice-free gravity drain , away from stagnation areas;
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a maintenance plan recommended to the customer to maintain clearances during snow periods and check the free circulation of water .
Implementation steps: safety, method and cleanliness
1) Preparation and securing
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Access by ladder and lifelines: our technicians work harnessed, with ladder stabilization and load control during handling.
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Membrane protection : work area mats and boards to prevent abrasion.
2) Handling and anchoring
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Installation of the aluminum frame, leveling and tightening to the torque.
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Installation of the condenser with anti-vibration pads under the legs, respecting the manufacturer's clearances .
3) Refrigeration connections
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Calibrated flares, torques checked with a dynamometer , nitrogen flushing during brazing if applicable, then nitrogen leak test .
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Deep vacuum controlled with a micron meter before release of the refrigerant.
4) Power on and commissioning
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Checking polarities , tightening and currents.
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Commissioning : testing in heating/cooling modes, recording of supply/return temperatures, subcooling/superheating, and validation of the airflow of the indoor head.
Challenges encountered and solutions applied
Snow and negative temperatures
Working on a snow-covered roof requires a weather window and enhanced safety protocols. We schedule critical steps (brazing, vacuuming, testing) within a more manageable time window and use mobile shelters as needed to protect connections.
Restricted access and logistics
The technical space of the roof requires a vertical supply route . Our team coordinates the raising of the material, the protection of the common areas and the restoration after the work: no trace, clean site .
Visual integration
The client wanted to avoid a visual impact on the courtyard side. The connections were discreetly routed to the technical passage; the chosen capping harmonizes with the color of the facings, for an elegant finish.
Result: 4-season comfort and better controlled bills
From the moment it is put into service, the Sharp wall-mounted heat pump ensures:
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stable and comfortable heating , even on frosty evenings;
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even cooling in summer, without unpleasant drafts;
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optimized consumption thanks to the inverter compressor and fine modulation of the ZU1 series.
The owner benefits from a future-ready system: R-32 refrigerant , cold climate performance and simplified HVAC maintenance thanks to the accessibility of the condenser and the quality of the connections.
AirGreen best practices and advice for this type of installation
Sizing and capacity selection
We recommend sizing the capacity (9k, 12k, 18k, 24k BTU depending on the configuration) based on a load calculation specific to the housing: surface area, insulation, orientation, infiltration, glazing, actual use of the rooms.
Snow management on flat roofs
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Maintain 50 to 60 cm of clearance around the unit;
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Avoid drifting snow on the battery;
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Check the defrost water drainage path regularly.
Preventive maintenance
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Cleaning of filters and inspection of the inner head every season;
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Annual check of refrigeration and electrical connections ;
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Check the crawl space under the chassis and the condition of the pads/anti-vibration mounts.
Grants and Eligibility
Quebec programs are evolving. For recent R-32 heat pumps with good low temperature performance, we support our clients in verifying eligibility and preparing supporting documents (model, capacity, performance ratings), in Montreal, Laval , Longueuil , North Shore and South Shore .
Why AirGreen for your heat pump in Montreal and surrounding areas?
Because we understand urban buildings and their constraints, and we deliver sustainable, clean, and compliant HVAC installations . Our commissioning process , comprehensive documentation provided to the customer, and after-sales service make the difference.
Whether you live in a plex in Rosemont , a condo in the Southwest , a house in Brossard or Boisbriand , we adapt the solution to your budget, your habits and your budget — without compromising on quality.
The job tools
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.
How the job unfolds
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 we check on a job like this one
Each number is a point we check on site. Switch between summer and winter to watch air and heat move.
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.
Is your home ready?
Check what applies at your place. A "no" is not a refusal: it is what we sort out during the estimate.
Good habits, once the unit is in place
Six simple habits that keep the unit going. Your list stays on this device.
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.
The right pages, at the right time
Four statements: true or false?
It all comes down to details you have just seen.
1. In heating mode, the outdoor unit can produce water.
During defrost cycles. That water must drain away without forming ice.
2. You pick the capacity with a simple square-footage rule.
Windows, insulation, orientation and how the room is used all count. Capacity is chosen on site.
3. A multi-zone connects several indoor heads to a single condenser.
One head per room, all on the same condenser. Each room keeps its own temperature.
4. The disconnect can sit behind the patio furniture.
It must stay accessible: it is what shuts the unit off for service.
0 / 4 right answers
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).