Installation of a Haxxair wall-mounted heat pump in Le Sud-Ouest
Haxxair wall-mounted heat pump installed on a flat roof in southwest Montreal. Anti-vibration base, sealed path, nitrogen and vacuum commissioning. AirGreen: Careful HVAC installation in Montreal, Laval, Longueuil, North Shore, and South Shore.
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.
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 HVAC installation designed to last, serving Montreal's comfort
In a residential building in the Sud-Ouest district , we installed a Haxxair wall-mounted heat pump with a condenser installed on a flat roof . The project required a clean, quiet installation that was resistant to the climatic conditions of Greater Montreal . Our team designed an optimized cooling path, a stable base on the roof, and meticulous commissioning to ensure efficient heating in winter and effective air conditioning in summer .
Background and objectives
The client wanted to modernize their system to reduce operating costs and improve comfort in a two-story 5 1/2-bedroom apartment. The constraints included access via a roof hatch, airflow potentially obstructed by gravel, and co-ownership rules requiring a discreet and reversible HVAC system . We selected a single-zone Haxxair , ideal for a Montreal apartment, with a compact wall-mounted indoor unit and an outdoor condenser on the roof.
What distinguishes a flat roof installation in downtown Montreal
The roofs of plexes and buildings in the Southwest (Saint-Henri, Little Burgundy, Griffintown) require specific technical choices. Our methodology:
Mechanical seating and vibration management
-
Installation of the condenser on structural pads with anti-vibration pads to prevent the transmission of noise to the structure.
-
Raising the unit above the gravel to ensure even airflow and prevent meltwater build-up.
-
Orientation of the batteries to limit the recycling of hot air in air conditioning mode and promote defrosting in heating mode.
Refrigeration path and sealing
-
Routing of the refrigerant lines from the interior head to the technical column , then crossing the roof using a waterproof roof pass-through.
-
Restoration of the air barrier and vapor barrier in accordance with good practices, in order to prevent infiltration and condensation in the envelope.
-
Communication cabling and power supply grouped and secured under cover for a neat and durable finish.
Condensate management
-
Gravity evacuation of the interior head, local services allowing a constant slope; as a backup, a low-noise lifting pump would have been provided.
-
Provision for winter clearance of the condenser for defrost water, essential for any heat pump operating in cold weather.
Rigorous commissioning by AirGreen
Our technicians apply the same discipline on each site, whether in Montreal, Laval, Longueuil, North Shore or South Shore .
Nitrogen leak test
-
Pressurization of the lines with dry nitrogen to validate the absence of micro-leaks at the beaten collars and flare connections.
-
Stabilization measured during an interval representative of thermal variations on the roof.
Deep vacuum draw
-
High vacuum with pump and digital vacuum gauge to reach a micron level attesting to a perfectly dehydrated circuit.
-
Refrigerant breakage and vacuum maintenance without rebound: a guarantee of compressor performance and longevity.
Configuration and functional testing
-
Checking load currents, temperature differences (flow/return) and defrosting strategy in heating mode.
-
Adjustment of ventilation speeds on the interior side to optimize acoustic comfort and seasonal efficiency.
Why choose Haxxair for a Montreal apartment?
Even without referencing a specific model , the Haxxair wall units used by AirGreen are distinguished by:
-
An exchanger sized for good air conditioning performance and heating performance in cold weather.
-
An inverter control to modulate power and limit on/off cycles.
-
Contained acoustics , essential in a dense urban environment.
-
Efficient defrosting electronics, reducing cycle times and maintaining stable comfort .
Depending on the selected BTU capacity and efficiency (SEER/HSPF), these appliances may be eligible for certain financial assistance programs . We always validate, on a case-by-case basis, the eligibility of projects in Montreal, Laval, Longueuil, North Shore and South Shore .
Highlights of this construction site in the Southwest
-
Haxxair condenser installed on a flat roof with anti-vibration riser.
-
On-site commissioning tools : manifold, vacuum gauge, vacuum pump, nitrogen bottle for pressure testing.
-
Disconnect box installed nearby (outside water stagnation areas), protected cable and tight routing.
-
UV coating on the connections, consistent with the color of the roof accessories.
-
Finishes: stainless steel attachments and sealed roof passage for lasting watertightness .
Result for the customer
-
Rapid rise in comfort from the first minutes in air conditioning.
-
Thermal stability in heating despite the temperature fluctuations typical of the Lachine Canal.
-
Minimal noise in the home thanks to vibration decoupling and fine adjustment of the fan speed.
-
HVAC maintenance clarified: washable interior filter, seasonal inspection, coil cleaning and connection verification.
Good practices and pitfalls to avoid on roofs
-
Never place a condenser directly on the gravel : this accelerates corrosion and disrupts the air intake.
-
Systematically protect the roof passage: air barrier, vapor barrier and membrane-compatible sealant .
-
Provide winter drainage for defrost water; on roofs, avoid areas of accumulation.
-
Install an external circuit breaker and check the grounding .
-
Plan annual maintenance : cleaning, checking pressures/parameters, leveling supports.
AirGreen expertise in Greater Montreal
AirGreen supports condominiums, plexes and individual homes with adapted HVAC solutions: wall-mounted heat pumps , multi-zone , central systems , quality accessories and responsive after-sales service. Our teams master the varied contexts of Montreal intramural , as well as the logistical requirements of Laval , Longueuil , the North Shore and the South Shore . Each project is documented, tested and delivered with clear instructions for use and maintenance.
Maintenance recommended to maintain performance
-
Bi-monthly filter cleaning during peak season.
-
Gentle washing of the interior evaporator and inspection of the condensate drain.
-
Dusting the condenser and checking the horizontality of the supports.
-
Checking electrical parameters and tightness of connections.
-
Annual HVAC maintenance report: it extends the lifespan and maintains seasonal performance .
Conclusion
This Haxxair installation on a flat roof in southwest Montreal demonstrates the benefits of a structured approach: stable mechanical foundation, sealed refrigeration path, instrumented commissioning and a clear maintenance plan. The result: four-season comfort , controlled consumption and discreet integration, perfectly adapted to Montreal's urban fabric.
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 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 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.
- 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.
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. 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.
More jobs to see, near you
By town, by equipment or by region: browse more than 4,700 published projects.
Each dot: a town where AirGreen has published projects. The glowing dot: this job.
Every house has its constraints. We see them before we install.
The on-site estimate is free and the quote follows within 24 hours.
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).