A high-level installation where quality is ensured even before startup
For this project in LaSalle, our team had to install a Samsung WindFree™ MaxHeat wall-mounted heat pump in a residential building with a flat roof. The outdoor unit therefore could not simply be placed at ground level near an exterior wall. The equipment had to be transported to the roof, a location compatible with the existing mechanical systems had to be selected, the membrane had to be protected, and every commissioning step had to be organized in an exposed environment.
The photograph taken during the work shows a decisive stage of the HVAC installation. The service panel of the Samsung unit has been removed, the internal components are accessible, and our technician is using a professional manifold connected to the refrigeration circuit. The red, blue, and yellow hoses make it possible to perform the required checks before final commissioning.
The regulator and equipment used to pressurize the circuit can also be seen nearby. This image does not simply show a heat pump placed on a support: it shows the technical work required to ensure that the unit operates properly during Montreal’s humid summers and Quebec’s cold winter periods.
Why install the outdoor unit on the roof?
In many buildings in LaSalle, particularly condominiums, multifamily buildings, and buildings with limited space around the foundation, the roof is sometimes the best location for the outdoor unit of a wall-mounted heat pump.
This solution makes it possible to:
- clear balconies and common areas;
- limit clutter near entrances;
- keep the equipment away from traffic areas;
- maintain a more unobstructed façade;
- reduce the risk of accidental damage;
- make it easier to distribute multiple units throughout a building;
- comply with certain zoning or condominium requirements.
However, a rooftop installation involves constraints that do not always exist in a standard residential project. Planning must account for the membrane, wind, snow accumulation, drainage, maintenance access, and vibrations transmitted to the structure.
We must also plan the route of the refrigerant lines, communication wiring, and condensate drain between the indoor unit and the roof. A poorly planned installation can result in unnecessarily long lines, difficult-to-seal penetrations, or a unit that is complicated to service.
A unit installed on a raised structure
In the photo, the Samsung outdoor unit rests on a raised metal structure. This detail is important for a heat pump intended for winter heating.
When the unit operates in heating mode, frost may accumulate on the outdoor coil. The heat pump then periodically initiates a defrost cycle. The resulting water must be able to drain beneath the unit without remaining trapped in its base.
An installation that is too low on a roof could contribute to:
- the formation of an ice block beneath the unit;
- blocked drainage openings;
- snow accumulation around the coil;
- reduced airflow;
- vibrations caused by contact with ice;
- insufficient accessibility during the winter.
The Samsung WindFree™ MaxHeat has a built-in heating element in the bottom pan to facilitate water drainage during defrost cycles. It is designed to continue providing heat at outdoor temperatures down to approximately -30 °C. Samsung also indicates that the product line maintains high capacity at low temperatures and is designed for cold climates.
However, the support must be properly sized and installed. A heating element cannot compensate for poor drainage, a unit buried in snow, or an unstable structure.
A 12,000 BTU Samsung WindFree™ MaxHeat suited to Montréal’s climate
For this project, we selected a 12,000 BTU/h Samsung WindFree™ MaxHeat R32 configuration. The system includes a wall-mounted indoor unit and an outdoor unit with a variable-speed compressor.
The 12,000 BTU pairing offers the following features, among others:
- rated cooling capacity of 12,000 BTU/h;
- efficiency of up to 24.0 SEER2;
- heating efficiency of 10.5 HSPF2;
- instantaneous efficiency of 14.1 EER2;
- heating operation down to approximately -30 °C;
- refrigerant R32;
- integrated Wi-Fi control;
- ENERGY STAR® Cold Climate certification;
- indoor sound level as low as approximately 22 dB(A), depending on the mode;
- 208/230 V power supply according to the unit’s requirements.
For this combination, the published capacity at -8 °C is approximately 10,600 BTU/h, while the available capacity gradually decreases as the outdoor temperature becomes colder. This information is much more useful than a simple statement that it “operates at -30 °C,” because it helps determine the heat pump’s actual contribution to heating the home.
A heat pump capable of operating at very low temperatures does not automatically replace every other heating system. The decision depends on the home’s heat load, room layout, insulation, and the actual capacity available at Montréal’s design temperatures.
WindFree™ comfort in living spaces
WindFree™ mode sets this heat pump apart from many traditional wall-mounted systems. After bringing the room close to the desired temperature, the indoor unit can close its main louver and distribute conditioned air through numerous microperforations.
The air is therefore distributed more gently throughout the room, without maintaining a cold draft directly toward the occupants. Samsung describes this operation as creating very slight air movement, better suited to maintaining the temperature.
This technology is particularly relevant when the indoor unit is located:
- in a bedroom;
- above a sofa;
- facing a work table;
- in an open-concept area;
- near an area where occupants remain seated for long periods.
However, WindFree™ mode does not correct a poor placement choice. We must position the indoor unit to facilitate air circulation in the main area while avoiding obstacles, beams, tall cabinets, and walls that could interrupt the distribution.
Sizing a heat pump without relying solely on square footage
A 12,000 BTU capacity should never be selected solely based on a quick estimate of the floor area. Two homes of identical size in LaSalle may have very different needs.
We analyze, among other things:
- the area that is actually open to air circulation;
- the ceiling height;
- the number of exterior walls;
- the orientation of the windows;
- the quality of the insulation;
- air infiltration;
- the floor on which the home is located;
- the roof’s exposure to the sun;
- the heat gains produced by occupants and appliances;
- the existing heating system.
A home located on the top floor may receive more heat through the roof during the summer. Conversely, its winter heating demand will depend heavily on the ceiling insulation and the building’s airtightness.
An oversized unit may reach its setpoint too quickly, reduce its modulation time, and dehumidify less effectively. An undersized model may run continuously without maintaining comfort during extreme conditions. Our goal is therefore to select a capacity suited to the actual load, not simply install the largest unit compatible with the available space.
The refrigeration line routing to the roof
A rooftop installation requires carefully organized routing between the indoor evaporator and the outdoor condenser. The copper lines carry the refrigerant, while a cable provides power or communication between the two units, depending on the configuration.
For the illustrated 12,000 BTU Samsung WindFree™ MaxHeat, the line diameters are generally 1/4 in. for the liquid line and 3/8 in. for the gas line. These dimensions must exactly match the requirements of the installed model.
The routing must avoid:
- unnecessarily tight bends;
- crushed lines;
- excessive exposure without protection;
- direct contact with sharp metal edges;
- points where water could seep in;
- unsupported sections;
- poorly sealed roof openings.
We also protect the insulation on the refrigeration line. On a roof, UV rays, temperature variations, and birds can accelerate its deterioration. Clean exterior protection reduces this risk and makes future inspections easier.
Pressurization, evacuation, and checks: the unseen steps that determine reliability
The leak-tightness check visible in the photo
One of the central elements of this installation in LaSalle is checking the refrigeration circuit. The outdoor unit’s panel is opened to provide access to the valves, connections, and service components.
After making the flared connections on the copper lines, we pressurize the circuit with dry nitrogen. This step verifies that the connections and lines are leak-tight before releasing the outdoor unit’s refrigerant charge.
The manifold visible in the photo allows the technician to monitor the pressure accurately. Stable pressure, combined with appropriate detection methods, helps confirm that there is no leak.
This procedure is essential because a slow leak may not produce any immediate symptoms. The system may operate properly for several weeks before gradually losing capacity. Possible consequences include:
- reduced efficiency;
- increased consumption;
- ice formation on the evaporator;
- compressor overheating;
- a loss of heating during the winter;
- an avoidable repair intervention.
We therefore do not consider a connection reliable simply because it appears tight.
Why we use dry nitrogen
Dry nitrogen is used because it is stable and free of moisture. It allows the system to be pressurized without introducing water into the refrigeration circuit.
Ordinary compressed air is not suitable for this operation. It contains moisture and can contaminate the system. Pressurized oxygen also presents risks when it comes into contact with certain products or oils.
Nitrogen testing also allows us to inspect the fittings before proceeding with evacuation. When an issue is detected at this stage, we can remake the affected connection without having to recover a refrigerant charge that has already been released.
A measured vacuum, not just a timed one
After the leak test, the nitrogen is evacuated and a vacuum pump is connected to the circuit. The goal is to remove the air, non-condensable gases, and moisture contained in the pipes.
A common mistake is to run the pump for an arbitrary number of minutes and then consider the job complete. Time alone does not confirm the quality of the vacuum. It varies according to:
- the length of the pipes;
- their diameter;
- the outdoor temperature;
- the pump’s capacity;
- the condition of the hoses;
- the amount of moisture present;
- the tightness of the installation.
A professional installation relies on an actual vacuum measurement and a hold test. If the pressure rises abnormally after the pump is isolated, moisture or a leak may remain in the system.
This step protects the oil and compressor. A highly efficient heat pump cannot deliver its expected performance when its circuit has been contaminated during installation.
Working cleanly on a roofing membrane
The photo shows the tools grouped in the technician’s immediate vicinity. On a flat roof, site organization serves both a technical and a safety function.
The screws, panels, and small parts removed from the unit must be checked. A screw left on a membrane can be stepped on and cause a puncture. Heavy tools and service cylinders must also be stabilized to prevent falls or damage to the roofing.
We pay particular attention to the following points:
- Protect traffic areas;
- Avoid dragging metal panels across the membrane;
- Keep the fittings and valves clean;
- Secure the hoses;
- Retrieve all screws after closing the unit;
- Check the condition of the roof around the support;
- Do not obstruct the roof drains.
The unit must also remain accessible without requiring a technician to walk on pipes, move another appliance, or dismantle a nearby installation.
The immediate vicinity of mechanical equipment
The Samsung unit was installed near a mechanical box and several rooftop systems. This type of environment requires keeping sufficient space for ventilation and servicing.
The air discharged by the fan must not be blocked by a wall, parapet, or another unit. We must also avoid having the heat pump re吸 its own discharged air, which could reduce its efficiency.
The final location must allow for:
- removal of the service panel;
- access to the valves;
- coil cleaning;
- checking the electrical connections;
- potential component replacement;
- adequate airflow;
- clearance for snow around the unit.
Appearance matters, but it must not take precedence over mechanical requirements. A perfectly aligned unit that cannot be serviced is a poor installation.
R32: an installation requiring a rigorous method
This generation of Samsung WindFree™ MaxHeat uses R32 refrigerant. This fluid offers good thermodynamic properties and is now used in several high-efficiency systems. The technical data sheet for the 12,000 BTU configuration confirms the use of R32.
Like any refrigerant, it must be handled with the appropriate equipment. The technician must comply with the manufacturer's requirements regarding tools, ventilation, line lengths, additional charge, and commissioning procedures.
The electrical connections must also be made according to the nameplate. For the configuration shown, the label indicates, among other things, a minimum circuit ampacity of approximately 12 A and a maximum protection of 20 A, subject to the nameplate of the actual unit delivered and the electrical requirements applicable to the job site.
We never select a circuit breaker solely based on the nominal BTU capacity. The manufacturer's MCA and MOP values must guide the electrical work.
Startup and complete validation
Once the leak test and evacuation are complete, we can open the service valves and start the system.
Commissioning includes several checks:
- communication between the indoor and outdoor units;
- compressor startup;
- fan operation;
- air temperatures in heating and cooling modes;
- pressure stability;
- absence of error codes;
- operation of the louvers;
- activation of WindFree™ mode;
- condensate drainage;
- Wi-Fi control, when configured;
- absence of vibration or unusual noise.
The outdoor panel is then put back in place with all its screws and protective devices. This closure is performed only after confirming that the connections are secure and that nothing has been left inside the unit.
Potential eligibility for the LogisVert grant
The 12,000 BTU Samsung WindFree™ MaxHeat is certified ENERGY STAR® for cold climates. However, the model combination and installation date must still be verified in Hydro-Québec’s official tool before confirming the amount of financial assistance.
The fact sheet for this configuration indicates a capacity of approximately 10,600 BTU/h at -8 °C and estimated standard assistance of $1,272, subject to the building’s eligibility, the installation date, and the rules in effect when the application is submitted.
Hydro-Québec specifies that the amount depends on the model and the applicant’s situation. The application must generally be submitted within nine months of installation. For certain multi-unit buildings meeting specific criteria, the assistance may be increased to $220 per 1,000 BTU/h at -8 °C for a cold-climate-certified wall-mounted heat pump. This increase does not automatically apply to all buildings.
We recommend keeping:
- the detailed invoice;
- the indoor and outdoor model numbers;
- the AHRI or ENERGY STAR® number;
- the installation date;
- proof of payment;
- photographs of the nameplates;
- the documents required for the type of residence.
What this LaSalle installation demonstrates in practical terms
This project illustrates why choosing the right wall-mounted heat pump is only one part of the project. Final performance also depends on the support, piping, sealing, vacuum, drainage, electrical installation, and commissioning.
In this flat-roof installation, our team had to combine:
- planning adapted to a residential building;
- a raised structure for winter conditions;
- unobstructed airflow;
- a protected refrigerant line route;
- a nitrogen leak test;
- a complete vacuum;
- a check of the operating parameters;
- safe work organization on the roof.
These steps are rarely visible once the panel has been closed. Yet they determine the system’s reliability for years to come.
At AirGreen, we apply this same rigor to our installations of wall-mounted heat pumps and air conditioners in Montreal, Laval, Longueuil, the North Shore, and the South Shore. Every project presents different constraints: a flat roof, balcony, masonry wall, condominium, limited access, long piping runs, or proximity to neighbours.
Our role is to adapt the HVAC system to the building, rather than forcing the building to adapt to a standardized solution.