Installation of a Fujitsu Airstage central heat pump in Ville-Marie
Installation of a Fujitsu Airstage central heat pump in Ville-Marie: an AirGreen flat roof project combining performance, reliability and HVAC expertise in the heart of Montreal.
Take a tour of the installation
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.
It captures or rejects heat outside. It sits on a level base, above the snow, with free space all around.
The insulated refrigerant lines enter the house through a sealed opening and run to the indoor coil.
A shut-off switch near the outdoor unit isolates it safely for service.
Sitting on the indoor module, it moves heat between the house air and the refrigerant.
Electric furnace or air handler: its fan pushes air through the ducts. The electric backup takes over in extreme cold.
Supply ducts bring air to the rooms; returns bring it back to the unit. Their condition matters as much as the unit's.
It protects the coil and the fan. A dirty filter cuts airflow, so it gets checked regularly.
It runs the heat pump and the backup heat. It must be compatible with the installed system.
A technical installation on a flat roof in the heart of the city center
At AirGreen , we recently completed the installation of a Fujitsu Airstage central heat pump in a residence located in Ville-Marie . This project illustrates the unique challenges associated with urban buildings with flat roofs, where space optimization and solid support are essential to ensure the performance and longevity of the equipment.
Project background
The client was looking for a reliable heating and cooling solution capable of meeting the needs of a home in the heart of downtown Montreal. The main criteria were:
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Performance in all seasons , even in extreme cold.
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Discreet installation to preserve interior living space.
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Durability and resistance to climatic constraints specific to Montreal flat roofs (snow, wind, rain).
Choice of equipment
The Fujitsu Airstage central heat pump was distinguished by:
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Its advanced VRF (Variable Refrigerant Flow) technology allows the power to be adapted according to actual needs.
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Its high energy efficiency , reducing annual operating costs.
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Its compatibility with Quebec grant programs related to energy-efficient systems.
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Proven robustness for exposed outdoor installations.
Installation Steps
1. Preparation of the support on a flat roof
The outdoor unit was fixed on a raised metal base , itself placed on treated beams resting on protective pads. This assembly ensures:
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Perfect stability even in strong winds.
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Protection against the accumulation of snow and water on the roof.
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Optimal weight distribution to preserve the watertightness of the roof covering .
2. Routing of refrigerant connections
The refrigeration pipes and electrical cables were routed through a discreet technical entrance , minimizing the length of the connections and thus reducing energy losses. Particular care was taken in insulating the pipes to avoid any unwanted condensation.
3. Condensate management
On a flat roof, drainage is always a challenge. We have integrated a solution allowing efficient evacuation of condensate , without the risk of stagnation or infiltration into the building.
4. Commissioning and calibration
Our technicians carried out:
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Pressure tests to ensure the network is watertight.
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Electronic verification of parameters to ensure optimal performance.
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Calibration of the air flow according to the zones served by the central heat pump.
Challenges encountered and solutions provided
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Limited roof access : equipment was transported using a suitable lifting system, avoiding any disruption to occupants.
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Climate constraints : the installation was planned to comply with the safety conditions for working at height in an urban environment.
Results obtained
The customer now benefits from:
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Consistent comfort in all seasons , thanks to the intelligent modulation of the Fujitsu Airstage.
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A durable and secure installation , designed to withstand Montreal's harsh winters.
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A significant reduction in energy costs and carbon footprint.
Why choose AirGreen for your flat roof installations?
Our teams are experts in complex HVAC installations in dense urban environments. Whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore , we adapt each project to the building's real-world constraints:
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Proven technical expertise in central heat pumps and VRF.
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Compliance with safety and waterproofing standards .
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Complete support , from system selection to optimization for subsidies.
The big day, step by step
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the ducts, the current indoor module, the electrical panel and the planned spot for the outdoor unit.
The equipment combination, capacity and price, in writing. We check whether the combination qualifies for assistance programs.
Access protected, old unit disconnected and removed when it is being replaced.
Electric furnace or air handler, with its coil, connected to the supply and return ducts.
On a level base, raised above the snow, with free space all around.
Insulated, they enter through a sealed opening and run to the indoor coil.
Dedicated circuits, accessible disconnect, a thermostat that works with the heat pump and the backup heat.
Leak test, vacuum, start-up, airflow check and a test of both modes.
Filter, thermostat, backup heat in extreme cold: what to know before winter.
- The on-site estimateWe look at the ducts, the current indoor module, the electrical panel and the planned spot for the outdoor unit.
- The quoteThe equipment combination, capacity and price, in writing. We check whether the combination qualifies for assistance programs.
- Getting readyAccess protected, old unit disconnected and removed when it is being replaced.
- The indoor moduleElectric furnace or air handler, with its coil, connected to the supply and return ducts.
- The outdoor unitOn a level base, raised above the snow, with free space all around.
- The refrigerant linesInsulated, they enter through a sealed opening and run to the indoor coil.
- Electrical and thermostatDedicated circuits, accessible disconnect, a thermostat that works with the heat pump and the backup heat.
- Tests and start-upLeak test, vacuum, start-up, airflow check and a test of both modes.
- The walkthroughFilter, thermostat, backup heat in extreme cold: what to know before winter.
What would it look like at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
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.
Four mistakes we do not make
Flip each card to see what we do instead.
Your own project, step by step
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Check the indoor module's filter.
- Clear winter debris from the outdoor unit.
- Test cooling before the heat arrives.
- Check the filter more often in peak season.
- Keep registers and returns clear.
- Watch condensate drainage near the coil.
- Change or clean the filter.
- Test heating and backup heat before the cold.
- Book periodic maintenance.
- Clear snow around the outdoor unit.
- Store nothing in front of the indoor module.
- Note any unusual noise or smell and call us.
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.
Four statements: true or false?
It all comes down to details you have just seen.
1. A central heat pump uses the house's ducts.
It connects to the existing ducts to heat and cool everywhere.
2. In extreme cold, electric backup heat can take over.
The indoor module (furnace or air handler) works with the heat pump and takes over in extreme cold.
3. The filter only gets changed when the unit breaks down.
A dirty filter cuts airflow. It gets checked regularly.
4. You can reuse the old unit's size without checking.
The house may have changed: insulation, windows, added rooms. Capacity is confirmed on site.
0 / 4 right answers
What people ask us about this kind of work
Can I keep my current ducts?
What happens in extreme cold?
Furnace, air handler, ducted: what is the difference?
Are there grants?
Do I need a permit?
How much can I save?
How is the LogisVert assistance calculated?
Will my current thermostat work?
Central or wall units: which one?
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).