A rooftop installation designed to replace an aging configuration and ensure reliable winter operation
This Samsung WindFree™ MaxHeat wall-mounted heat pump installation in Bois-des-Filion stands out because of its location on a flat roof, amid several outdoor units already in place. This type of project requires much more extensive planning than a ground-level or balcony installation, since we must consider the roof’s watertightness, support stability, line routing, wind, snow, vibration, and future access for maintenance.
The jobsite photo clearly shows the environment in which our technicians worked. Several condensers were already occupying the roof, including equipment installed on aging wooden supports. The new unit was positioned on a separate metal support, raised above the membrane and resting on bases designed to distribute the load without unnecessarily puncturing the roof covering.
The refrigerant line set runs along the roof before reaching the outdoor unit. We also protected and secured the lines so they would remain stable despite wind, temperature fluctuations, and future work on the building.
In this context, our goal was not simply to install a functional Samsung heat pump. We had to create a durable, accessible solution compatible with an already crowded rooftop environment.
What the roof configuration revealed during the initial assessment
A flat roof may seem to offer plenty of space, but the area that is actually available is often limited by several constraints:
- other air-conditioning equipment;
- ventilation outlets;
- existing ducts and cables;
- roof drains;
- parapets;
- traffic areas;
- drainage slopes;
- fragile or repaired areas of the membrane;
- the required distances between the units.
On this Bois-des-Filion project, the units already installed occupied a significant portion of the area. Some were resting on wooden structures exposed to the elements. We therefore had to choose a location that would block neither the airflow discharge from nearby equipment nor access to the service panels.
The new heat pump was positioned to preserve a clear area around its heat exchanger and ventilation. Its metal support keeps the unit above the roof while leaving sufficient space beneath the cabinet for water drainage and inspection.
Why a heat pump on a roof must be elevated
The outdoor unit visible on the right side of the photo rests on a metal structure installed above two protective wooden beams. This approach serves several technical purposes.
Reduce the risk of snow accumulation around the unit
In Bois-des-Filion, a flat roof can accumulate a significant amount of snow, particularly near parapets and obstacles that alter wind movement. A unit installed too low may become partially buried.
When snow blocks the heat exchanger or restricts airflow, the heat pump operates under poor conditions. Performance may decrease, defrost cycles may become more frequent, and certain components may be subjected to additional stress.
The height of the support must therefore be selected based on:
- expected snow accumulation;
- parapet height;
- wind exposure;
- the heat pump model;
- the clearance required by the manufacturer;
- building-specific requirements.
Facilitate defrost water drainage
In heating mode, an outdoor heat pump may accumulate frost on its coil. The system then performs a defrost cycle to melt this buildup.
The water produced must be able to drain beneath the unit. If the condenser is installed too close to the roof, this water may freeze directly against the base, block certain openings, or create a mass of ice beneath the cabinet.
The raised support leaves free space that helps limit this problem. However, ice buildup must be monitored throughout the winter, especially when equipment operates intensively in wet, cold weather.
Preserve access for maintenance
A unit placed directly on the membrane is more difficult to inspect. The additional height improves access to the lower parts of the cabinet and makes it possible to see whether water, ice, or debris is accumulating.
For our technicians, this access also makes it easier to:
- fastener inspection;
- insulation inspection;
- wiring verification;
- coil cleaning;
- component maintenance;
- vibration diagnostics.
A support that protects the roof membrane
A roof must not be treated like an outdoor concrete slab. Its membrane must remain intact to prevent water infiltration.
In this installation, the support was not simply placed directly on the roofing material. Protective elements distribute the weight and limit harsh contact with the membrane.
Poor installation can cause several problems:
- puncturing or abrasion of the membrane;
- excessive concentration of the load;
- water accumulation around the feet;
- movement of the support under the effect of wind;
- vibration transmitted to the structure;
- difficulty carrying out future roofing work.
We must also avoid obstructing the roof's natural drainage. The support bases and lines must not create a dam that traps rainwater or melting snow.
A new heat pump in the middle of several existing units
The photo shows at least three outdoor units in the same area. This density is common on the roofs of residential buildings, duplexes, triplexes, or small commercial buildings.
In this type of environment, we must assess the interaction between the units. A condenser discharges air that can be hot in cooling mode or cold in heating mode. If this air is immediately drawn in by a neighboring unit, the performance of both systems may be affected.
The new Samsung WindFree™ MaxHeat therefore had to be installed with sufficient clearances from the equipment already in place.
We check, in particular:
- the fan orientation;
- the location of the heat exchanger;
- the direction of the prevailing winds;
- the distance between the condensers;
- the relative height of the units;
- access to the electrical and refrigeration panels;
- the possibility of replacing a neighboring unit in the future;
- the safe access route for technicians.
An installation that seems acceptable in summer can become problematic in winter if the units discharge air toward each other or if snow accumulates between the supports.
Routing lines across an exposed roof
The refrigerant line visible in the photo runs across a significant portion of the roof before reaching the heat pump. This routing generally includes:
- the liquid line;
- the gas line;
- the insulation;
- the communication cable;
- certain electrical conductors, depending on the design;
- a protective coating or an exterior cover.
On a roof, the pipes are exposed to particularly demanding conditions:
- solar radiation;
- rain;
- freezing;
- snow;
- wind;
- rapid temperature changes;
- occasional movement of technicians;
- future work on the membrane.
The refrigerant-line insulation must remain continuous and well protected. Torn or deteriorated insulation can cause condensation, reduced efficiency, and accelerated deterioration of the materials.
We also secure the route so that it does not move in the wind. The supports must be properly spaced without crushing the insulation or creating stress points on the copper pipes.
The passage over the parapet
In the photo, the connection crosses the edge of the roof before descending along the exterior wall. This point deserves particular attention, as the copper must not be bent abruptly.
A bend that is too tight can:
- reduce the interior diameter;
- weaken the pipe;
- damage the insulation;
- create a vibration point;
- increase the risk of leaks over the long term.
We therefore create a gradual bend and protect the exposed section. The passage over the parapet must also be secured to prevent the pipes from constantly rubbing against the masonry or metal finish.
This part of the route is often overlooked in improvised installations. Yet it remains one of the areas most exposed to wind, ice, and movement caused by thermal expansion.
Why the Samsung WindFree™ MaxHeat was suitable for this installation
The Samsung WindFree™ MaxHeat is designed to provide cooling in summer and heating during the cold season. The range is particularly appealing to homeowners who want to use a heat pump for much of the Quebec winter.
Its variable-speed compressor adjusts the system’s output to actual needs. Rather than operating only at full capacity and then shutting off, the unit can modulate its operation to maintain a more stable temperature.
Inside, WindFree™ technology distributes air through a microperforated front panel. Once the desired temperature is reached, the system can reduce the sensation of a direct draft.
This feature is appreciated in:
- bedrooms;
- living rooms;
- offices;
- compact rooms;
- open areas where occupants are facing the unit.
The heat pump can first use its main louver to quickly reach the setpoint, then switch to gentler air distribution.
Capacity and efficiency: do not assume them from the photo
Although the image makes it possible to identify the brand and installation type, it does not make it possible to confirm the exact capacity of the unit.
Depending on the installed combination, a Samsung WindFree™ MaxHeat may be available in several capacities. The BTU rating, SEER2 efficiency, HSPF2 efficiency, and low-temperature performance must be verified using the complete indoor and outdoor unit model numbers.
For certain 12,000 BTU combinations, it is possible to achieve approximately 24 SEER2 and heating operation down to approximately −30 °C. An AHRI reference associated with certain combinations of this capacity is 215399291.
These data should not be applied automatically to all heat pumps bearing the WindFree™ MaxHeat name. We always confirm:
- both model numbers;
- the rated capacity;
- the low-temperature capacity;
- the AHRI number;
- the supply voltage;
- the MCA;
- the MOCP;
- pipe diameters;
- the maximum permitted length;
- the additional refrigerant charge, if applicable.
The refrigeration line length for a rooftop installation
A unit installed on a roof is often farther from the indoor unit than a condenser installed directly behind the wall.
The actual circuit length must include:
- horizontal sections on the roof;
- the descent along the building;
- sections concealed in a conduit;
- changes in elevation;
- vertical rises;
- detours imposed by the structure.
Each manufacturer specifies a maximum length and an allowable elevation difference. Some installations also require adding a specific amount of refrigerant beyond the precharged length.
Therefore, it is not enough to measure the straight-line distance between the two units. We must calculate the actual route and confirm that it complies with requirements before installation.
Leak testing and evacuation
Once the copper has been installed, the refrigeration circuit must be properly prepared before opening the service valves.
Our method includes, among other things:
- cutting and deburring the copper;
- preparing flared connections;
- tightening to the specified values;
- leak testing;
- evacuating the system;
- checking vacuum stability;
- opening the valves;
- system start-up;
- checking operating temperatures and pressures according to the conditions.
Evacuation allows the air and moisture present in the lines to be removed. On a long rooftop run, this step remains essential because the circuit’s internal volume may be greater.
A well-finished outdoor installation alone does not guarantee system reliability. The quality of the connections and commissioning is equally critical.
Managing vibrations on a flat roof
A variable-speed compressor heat pump generally operates quietly, but all mechanical equipment produces some level of vibration.
On a roof, this vibration can be transmitted to the building’s structure if the support is not suitable. Occupants may then hear a humming sound indoors, even if the outdoor noise seems low.
We must therefore consider:
- the rigidity of the support;
- the distribution of support points;
- the presence of vibration-control materials;
- the proximity of load-bearing walls;
- the position relative to the bedrooms;
- the compressor speed;
- the cabinet’s stability.
The metal support visible in the photo keeps the unit independent of the membrane while distributing the load. Depending on the building’s characteristics, additional vibration-control devices may be considered.
Wind and equipment anchoring
A flat roof is much more exposed to wind than a balcony or a sheltered courtyard. The outdoor unit, support, and lines must therefore remain stable during gusts.
The fastening method depends in particular on:
- the building’s height;
- the area’s exposure;
- the weight of the condenser;
- the type of support;
- the membrane;
- the manufacturer’s requirements;
- the owner’s or manager’s constraints.
We avoid penetrating the roof without coordinating with those responsible for the building envelope. When permanent anchors are required, they must be waterproofed using a method compatible with the roofing system.
Safe access for HVAC maintenance
A rooftop installation must remain accessible after the work is completed. The technician must be able to reach the unit, open the panels, and use their instruments without stepping on the lines or risking losing their balance near the parapet.
In this project, the heat pump was placed in a space that allows access to its service sides. The refrigerant line set was kept close to the surface and secured so that it would not become a movable obstacle.
For the owner or manager, it is important not to modify this area by adding:
- construction materials;
- blocks;
- temporary equipment;
- loose cables;
- heavy objects;
- items blocking the fan.
A professional HVAC maintenance service should be able to be performed without having to move several neighboring installations.
Subsidies and the importance of the AHRI number
Certain cold-climate wall-mounted heat pumps may qualify for financial assistance in Quebec. The Samsung brand and the MaxHeat designation are good indicators, but they are not sufficient to confirm eligibility.
The verification must cover:
- the exact combination of units;
- the AHRI number;
- the recognized heating capacity;
- the applicable certification;
- the property type;
- the program in effect;
- the installation date;
- the required documents.
The owner should keep:
- the detailed invoice;
- proof of payment;
- model numbers;
- serial numbers;
- photos of the nameplates;
- the commissioning date;
- the contractor’s contact information and licence number.
A subsidy promise based solely on the product line name can lead to an unpleasant surprise. We verify the exact references before confirming an amount.
A Samsung rooftop installation designed to last in Bois-des-Filion
This Samsung WindFree™ MaxHeat wall-mounted heat pump installation in Bois-des-Filion demonstrates the specific requirements of a project carried out on a flat roof.
The new outdoor unit was installed on an elevated metal support, with load distribution suited to the membrane. Its location takes neighboring equipment, airflow, maintenance, snow, and water produced during defrost cycles into account.
The refrigerant line set was protected and secured on the roof before crossing the parapet. This section requires particular attention to prevent chafing, excessive bending, and damage caused by wind or sunlight.
The project’s success is not limited to the visible unit. It also depends on proper sizing, copper line preparation, leak testing, evacuation, electrical power supply, and a complete system check after start-up.
At AirGreen, we carry out wall-mounted heat pump installations in Bois-des-Filion, Montreal, Laval, Longueuil, on the North Shore and the South Shore. Each project is planned according to the building’s actual structure, whether the installation is on the ground, on a balcony, on a wall, or on a roof already occupied by several pieces of equipment.