Two independent systems installed on a foundation wall in a particularly restricted outdoor space
This wall-mounted heat pump installation in Côte-des-Neiges–Notre-Dame-de-Grâce perfectly illustrates a common reality in the central neighbourhoods of Montreal: the space available for positioning outdoor units is sometimes much more limited than the desired heating or cooling capacity.
In this brick residential building, we had to integrate two Samsung WindFree™ MaxHeat wall-mounted heat pumps into a narrow rear passage already occupied by a wooden deck, basement windows, existing ducts, and various façade elements. A ground-level installation would have reduced circulation space, exposed the units more to snow accumulation, and complicated access to the windows at the lower level.
We therefore chose a wall-mounted configuration on metal brackets, with both outdoor units installed side by side at heights suited to the building. The result is a compact, accessible, and visually orderly installation, while preserving the space required for airflow and future maintenance.
A layout planned before the first hole is drilled
In a narrow yard in Côte-des-Neiges–Notre-Dame-de-Grâce, a few centimetres can make a significant difference. Positioning an outdoor unit is not simply a matter of finding a free section of wall. We must consider all of the following simultaneously:
- of the windows and their opening;
- of the clearance in front of the fans;
- of the distance between the two units;
- of access to the service panels;
- of the snow accumulation height;
- of the routing of the refrigerant lines;
- of water runoff during defrost cycles;
- of the strength of the wall support;
- of the vibrations transmitted to the structure;
- of the circulation space on the deck.
The project photograph clearly shows the constraints encountered. The façade combines an upper brick section with a foundation covered in pale render. Two basement windows are located directly beneath the equipment. The wooden deck occupies almost the entire available width, leaving little room to work with tools, ladders, and equipment.
Before installing the brackets, we determined a position that would keep the units above the openings, without preventing their use or placing the appliances too close to the exterior floor. This preparation avoids costly adjustments once the lines have been connected.
Why install two independent heat pumps?
In this project, using two separate systems makes it possible to serve two distinct areas of the building with independent regulation. Each space can therefore be heated or cooled according to its actual occupancy, without imposing the same temperature on the entire building.
This approach offers several practical advantages:
- a separately adjustable temperature in each zone;
- better control of energy consumption;
- fewer conflicts between occupants' preferences;
- adjustment suited to the needs of each space;
- independent access to controls and schedules;
- a maintenance intervention targeted at a single system.
However, this configuration should not be confused with a multi-zone heat pump connected to a single outdoor unit. Here, each outdoor unit belongs to its own system. This distinction affects electrical sizing, refrigerant connections, maintenance, and equipment control.
A wall-mounted installation designed for Montreal winters
The outdoor units were placed on robust metal wall brackets, anchored into an appropriate part of the structure. Each appliance rests on anti-vibration pads visible beneath its feet.
These pads serve several purposes:
- reduce vibration transmission to the wall;
- limit resonance inside the building;
- protect the metal support points;
- stabilize the appliance;
- facilitate precise leveling.
High-mounted installation is particularly relevant for a wall-mounted heat pump in Montreal. During winter, the outdoor unit must remain clear despite snow, ice, and the water produced during defrost cycles. An unit placed too low may become surrounded by compacted snow or ice buildup that gradually blocks the lower part of the appliance.
However, the choice of height must not be improvised. An excessively high-mounted unit becomes more difficult to inspect, clean, or repair. At AirGreen, we therefore seek a balance between winter protection, technical access, and integration with the façade.
Two units positioned close together without compromising their ventilation
Installing two outdoor units side by side requires particular attention. Each heat pump’s fan must be able to move a significant volume of air without the other appliance interfering with its operation.
We aligned the units while maintaining functional spacing between them. The larger unit is positioned slightly higher and farther forward on the available section, while the second occupies the adjacent space. This arrangement takes into account the wall’s geometry, the window below, and the obstacles in the passageway.
The space in front of the grilles remains open. No closed panel, guardrail, or decorative screen traps the discharged air. This precaution is essential because a heat pump that is too tightly enclosed may draw back in the air it has just expelled, reducing its efficiency and increasing the compressor’s operating time.
Samsung WindFree™ MaxHeat: comfort without direct drafts
Samsung’s WindFree™ technology is designed to maintain the temperature by gently diffusing air through numerous microperforations in the indoor unit when the main louver is closed. Samsung states that the air velocity produced in WindFree mode remains below the 0.15 m/s threshold associated with air considered practically still. This distribution is particularly appreciated in a bedroom, living room, or office where a stream of cold air directed at occupants can become uncomfortable.
The heat pump normally begins by reaching the requested temperature with a more direct airflow. It can then switch to WindFree mode to maintain that temperature with more even air distribution. This sequence avoids asking the low-air-movement mode to cool a very hot room quickly.
For occupants, this translates into more consistent comfort, particularly when the indoor unit must be installed above a sofa, near a bed, or in a room where positioning options are limited.
Technical data for the 12,000 BTU configuration
For the Samsung WindFree MaxHeat 12,000 BTU combination, consisting of the AR12DXDACWKXCV outdoor unit and the AR12DXDABWKN indoor unit, the reference number is AHRI 215399291.
This combination offers, among other benefits:
- a rated cooling capacity of 12,000 BTU/h;
- a rated heating capacity of 12,000 BTU/h;
- a seasonal efficiency rating of SEER2 24;
- an efficiency rating of EER2 14.1;
- a heating efficiency rating of HSPF2 10.5 for Region IV;
- a continuously modulating compressor;
- cold-climate certification;
- the R-32 refrigerant.
The published heating capacity is 10,600 BTU/h at approximately -8 °C and 9,000 BTU/h at -15 °C. These figures show why the choice of a heat pump should not be based solely on the nominal capacity indicated in its name. The available performance as the outdoor temperature drops is much more relevant for an installation in Quebec.
Sizing is not limited to floor area
A 12,000 BTU heat pump is often automatically associated with a certain floor area. However, this quick method can lead to the wrong choice.
Two dwellings of identical dimensions can have very different needs depending on:
- the year of construction;
- the quality of the insulation;
- the number and type of windows;
- sun exposure;
- ceiling height;
- the presence of exterior walls;
- the floor of the dwelling;
- air infiltration;
- the layout of the rooms;
- the existing heating system.
In a neighbourhood such as Côte-des-Neiges–Notre-Dame-de-Grâce, buildings can have very different envelopes. Some brick buildings have been improved over the years, while others retain less efficient windows, walls, or foundations.
At AirGreen, we therefore assess the actual configuration of the space before recommending a capacity. An oversized unit can reach its setpoint too quickly and reduce its ability to modulate effectively. An undersized unit, on the other hand, may run continuously without meeting the demand during the coldest periods.
A clean installation despite passageway constraints
The final appearance matters, especially when two units occupy the same façade. The supports were aligned to avoid a disorderly installation. The units are close enough together to maintain a compact arrangement, but they are not compressed against each other.
The connections were also organized so they would not block the passageway. The visible cables and lines at the bottom of the units follow a controlled route into the building. AirGreen stickers affixed to each unit make it easy to quickly identify the installer and access the contact information needed for future HVAC maintenance or a service request.
Finishing an HVAC installation is not limited to hiding the lines. It also includes:
- aligning the equipment;
- tightening the fasteners;
- protecting the connections;
- identifying the systems;
- sealing wall penetrations;
- maintaining safe access to the panels;
- drainage verification;
- the cleanliness of the worksite when the team leaves.
The R-32 refrigerant and the visible A2L labels
The safety labels visible on the outdoor units identify equipment using a refrigerant in the category A2LIn this generation of Samsung heat pumps, the refrigerant used is R-32.
The A2L category corresponds to a refrigerant with low flammability. Its use requires procedures adapted for transport, installation, evacuation, leak testing, and servicing. Technicians must use the appropriate tools and follow the manufacturer’s instructions.
For the homeowner, the presence of the flammability symbol on the label does not indicate that the unit is dangerous when properly installed. It means that work must be entrusted to a qualified HVAC company familiar with the requirements applicable to new refrigerants.
Points to check before a similar installation in Montréal, Laval, Longueuil, on the North Shore or the South Shore
Eligibility for the LogisVert program
An ENERGY STAR-certified cold-climate wall-mounted heat pump may qualify for financial assistance through Hydro-Québec’s LogisVert program. The amount depends on the recognized heating capacity at -8 °C, the exact unit combination, the installation date, and the building’s circumstances.
For an eligible cold-climate heat pump, the regular rebate is currently calculated at $120 per 1,000 BTU/h at -8 °C. The Samsung combination bearing AHRI number 215399291 has a recognized capacity of 10,600 BTU/h at this temperature, corresponding to an indicative amount of $1,272 per system, subject to application approval and the list applicable on the installation date.
Some multi-unit buildings may qualify for an enhanced rebate, increasing the rate to $220 per 1,000 BTU/h at -8 °C. With an eligible capacity of 10,600 BTU/h, the indicative amount could then reach $2,332 per unit, potentially totaling $4,664 for two identical systems. However, this enhanced rebate is subject to several conditions, including a building with two or more dwelling units, built in 1995 or earlier and located in an area meeting energy poverty criteria.
Because lists and amounts can change, verification must always be carried out using the exact AHRI number and the actual installation date. Hydro-Québec specifies that the list in effect at the time of the work takes precedence.
Errors this installation helps prevent
Installing the units directly in the passage
In such a narrow yard, a ground-level installation would have occupied a significant portion of the terrace and increased the risk of accidental impact. It would also have placed the units closer to snow and debris.
Attaching the brackets without checking the structure
A brick veneer or stucco finish does not automatically provide a sufficient anchoring point. The fasteners must reach suitable structural support and be selected according to the existing structure.
Forgetting about vibrations
An outdoor unit mounted directly on metal without isolators can transmit more vibration to the building. The pads visible in this installation help mechanically separate the units from their supports.
Blocking the basement windows
The positioning must preserve window operation, maintenance access, and access to the windows. It is also necessary to prevent defrost water from continuously falling onto the frames or sills.
Placing two units too close together
A dual installation requires more planning than a single unit. Service clearances must be maintained, and the two units must be prevented from disrupting each other’s airflow.
Neglecting the drainage path
In heating mode, an outdoor heat pump produces water during defrost cycles. This water must be able to drain away without creating a sheet of ice in a passage used by occupants.
The result achieved in Côte-des-Neiges–Notre-Dame-de-Grâce
This installation brings together several elements that characterize our work at AirGreen:
- a precise analysis of the available space;
- a configuration suited to the building;
- two independent systems for better control;
- sturdy wall brackets;
- vibration isolators beneath each unit;
- adequate clearance above the windows;
- a compact and structured finish;
- preparation suited to Montréal’s climate;
- maintained access for maintenance and repairs.
The project demonstrates that a Samsung WindFree MaxHeat wall-mounted heat pump can be integrated neatly into an urban building, even when the backyard offers very little flexibility. The quality of the result depends as much on the equipment selection as on how each unit is positioned, supported, and connected.
At AirGreen, we carry out wall-mounted heat pump installations and complete heating, ventilation, and air conditioning projects in Montréal, Laval, Longueuil, the North Shore, and the South Shore. Each project is assessed based on the structure, heating requirements, room layout, outdoor access, and long-term maintenance needs.