An outdoor wall-mounted installation that frees up ground space without sacrificing stability
For this Fujitsu Aquila XLTH dual-zone heat pump installation in Terrebonne, our AirGreen team had to work with a narrow side space, a brick wall, a concrete foundation, and well-established landscaping. Plants at the base of the wall limited the ground-level options, while the passage had to remain accessible.
The chosen solution was to install the Fujitsu AIRSTAGE outdoor unit on a metal wall bracket secured to the foundation. This configuration keeps the heat pump above ground level, protects the landscaping, and clears the space around the house.
The photograph shows an especially clean installation: the unit is mounted high enough to remain clear of the snow, the braced supports provide good rigidity, and pads are placed under the unit's feet to limit vibration transmission. The marking R32 as well as the rating A2L are visible on the front panel.
This system serves two indoor zones from a single outdoor unit. The homeowner therefore benefits from heating and cooling adapted to two distinct areas, without having to install two separate compressors around the property.
Why a dual-zone system was the right choice in Terrebonne
A dual-zone heat pump allows two indoor units to be connected to a single outdoor unit. Each zone can be controlled independently with regard to temperature, fan speed, and several comfort settings.
This configuration is advantageous in a home where heating and cooling needs vary from one space to another. A room with extensive glazing can accumulate a great deal of heat in summer, while a north-facing bedroom remains cooler. A basement may also require a different strategy from the ground floor.
A dual-zone system is particularly suitable for the following layouts:
- a ground floor and a basement;
- an open area and a bedroom;
- a main house and an extension;
- one floor and a family room;
- two areas separated by a hallway;
- one room exposed to the sun and another with more shade.
The exterior advantage is also important. A single unit occupies the wall, reducing clutter, the number of visible connections, and the space required around the property.
A wall-mounted support installed on the foundation
The heat pump is attached to a metal support anchored to the concrete section of the foundation. This decision is important because the strength of the support depends directly on the quality of the anchoring surface.
The visible brick above is exterior cladding. It should not automatically be considered a structural element capable of supporting the weight and vibrations of an outdoor unit.
By anchoring the support to a suitable load-bearing surface, we obtain a more rigid installation that is better suited to long-term loads.
Why avoid attaching the unit only to the brick
A residential brick wall may consist of cladding separated from the main structure by an air gap. Attaching a heat pump directly to this cladding, without considering the structure behind it, can lead to:
- insufficient anchoring;
- cracks in the mortar;
- increased vibration transmission;
- progressive settling;
- damage to the cladding;
- instability during operating cycles.
The type of anchoring must therefore be chosen according to the actual composition of the wall. In this installation, the concrete section provided a better-suited base for the metal support.
A triangulated structure to withstand weight and vibrations
The support visible in the photo uses a triangulated geometry. The horizontal arms hold the heat pump, while the diagonal braces transfer the load to the wall-mounted uprights.
This shape is commonly used because it limits bending and improves stability.
An outdoor unit is subjected to several types of loads:
- its own weight;
- compressor vibrations;
- fan movement;
- variations caused by starting and modulation;
- wind;
- snow or ice that may accumulate around it;
- maintenance work.
A support that is too light may vibrate or deform over time. A properly sized structure keeps the unit level and reduces unwanted movement.
The pads beneath the heat pump’s feet
Pads are visible between the unit’s feet and the support arms. They help isolate some of the mechanical vibrations.
Even when a heat pump is considered quiet, the compressor and fan produce slight movements. If these vibrations are transmitted directly to the bracket and then to the foundation, they can become noticeable indoors.
Vibration management depends on several factors:
- the rigidity of the bracket;
- the type of wall;
- the quality of the anchors;
- the location in relation to occupied rooms;
- the leveling of the unit;
- the pads used;
- the tightening of the fasteners.
The goal is not to make the unit completely immobile, but to prevent normal vibration from being amplified by the building's structure.
A useful height for Terrebonne winters
The outdoor unit is installed well above the ground. This height protects the unit from several common winter problems.
Reducing the risk of snow obstruction
In Terrebonne and on the North Shore, snow accumulation can quickly reach the lower part of a heat pump installed too close to the ground.
Air passes through the coil located on the sides and rear of the unit. If snow blocks part of this surface, airflow decreases.
Possible consequences include:
- a reduction in heating capacity;
- more frequent defrost cycles;
- increased energy consumption;
- extended operation;
- greater ice accumulation;
- a reduction in indoor comfort.
By installing the unit on a wall bracket, we create clearance that helps the coil remain accessible to air even when snow accumulates near the house.
Allowing defrost water to drain
In heating mode, the outdoor coil may accumulate frost. The heat pump then initiates a defrost cycle to melt this layer.
The water produced must be able to drain beneath the unit. If the machine is installed too close to the ground or a slab, this water may freeze directly against the chassis.
The height of the bracket provides more space for drainage and delays the formation of an ice block beneath the unit.
However, you must plan where this water will flow. It must not create a slippery area in a walkway or accumulate against the foundation.
Protecting the landscaping
Plants are visible directly beneath and near the installation. The wall bracket made it possible to avoid installing a slab or base occupying a large amount of ground space.
This solution reduces the impact on the landscaping, but it still requires certain precautions.
Plants must not grow into the coil or block the side openings. They must remain sufficiently low and far away to preserve airflow.
Seasonal maintenance may be necessary to:
- trim leaves that are too close;
- remove debris;
- prevent stems from touching the fan;
- maintain access to the service panel;
- monitor moisture around the foundation.
The plants visible in the photograph are still sufficiently low, but their growth must be controlled over the seasons.
Adequate clearance in front of the fan
The heat pump's large front fan is oriented toward an open space. This arrangement allows the discharged air to disperse without immediately hitting a wall or obstacle.
Insufficient clearance can create recirculation. The discharged air then returns toward the coil, reducing the quality of heat exchange.
Excessive recirculation can cause:
- a loss of efficiency;
- reduced capacity;
- longer cycles;
- increased noise;
- less stable operation;
- increased compressor wear.
The front grille must also remain accessible for inspection and cleaning.
The vertical routing of the lines
The photo shows a vertical line-set cover installed above the unit. This type of finish protects the refrigerant lines and wiring while giving the installation a neat appearance.
In a dual-zone system, the outdoor unit must be connected to two indoor units. Depending on the route selected, the lines may run up the wall before branching off or connecting to the different areas.
The line-set cover protects:
- the copper pipes;
- the insulation;
- the communication cable;
- electrical conductors;
- certain connections depending on the configuration.
It also helps limit exposure to ultraviolet rays, rain, and accidental impacts.
The importance of continuous insulation
The refrigerant lines must be properly insulated. A break in the insulation can cause condensation and a loss of efficiency.
Outdoors, the joints must be protected against:
- water;
- UV rays;
- freezing;
- temperature fluctuations;
- insects;
- mechanical damage.
A clean finish is therefore not merely aesthetic. It directly protects the quality of the system.
R32 refrigerant and the A2L classification
The marking R32 is clearly visible on the unit. This refrigerant is used in several new-generation heat pumps.
Its A2L classification means that it has low flammability. When installed according to the prescribed procedures, it can be used safely, but it requires suitable tools and methods.
The installation must take into account:
- the manufacturer's requirements;
- the compatible tools;
- the leak test;
- the vacuuming;
- the amount of refrigerant;
- pipe dimensions;
- handling practices;
- of the ventilation of the spaces concerned.
Technicians must understand the characteristics of R32 and not automatically apply the same methods used for an older system using a different refrigerant.
Fujitsu Aquila XLTH combination options
Fujitsu’s H Series documentation presents outdoor units rated at 18,000, 24,000, 36,000, and 45,000 BTU/h. Depending on the model, they can power two to five indoor units.
For an 18,000 BTU/h outdoor unit intended for two zones, Fujitsu permits several indoor-unit combinations, including:
- 7,000 + 7,000 BTU/h;
- 7,000 + 9,000 BTU/h;
- 7,000 + 12,000 BTU/h;
- 7,000 + 15,000 BTU/h;
- 9,000 + 9,000 BTU/h;
- 9,000 + 12,000 BTU/h;
- 9,000 + 15,000 BTU/h;
- 12,000 + 12,000 BTU/h.
The tables can confirm whether a combination is permitted, but they do not replace a load calculation. Fujitsu recommends using its Design Simulator software to select H Series AIRSTAGE equipment.
The photographed rating plate is not clear enough to confirm this unit’s exact capacity with certainty. It is therefore best not to infer the number of BTUs solely from its external size.
A dual-zone heat pump designed for personalized comfort
Each zone has its own setting
The two indoor units can be controlled separately. One room can be set to a different temperature from the other, depending on occupancy and the desired comfort level.
This control is useful when:
- a zone is used only in the evening;
- a bedroom must remain cooler;
- a room receives more sunlight;
- a space is rarely occupied;
- the two floors respond differently.
Zoning makes it easier to adapt operation to the building’s daily routines.
One important limitation: the mode is shared
A multi-zone system can heat or cool, but it generally cannot do both at the same time.
This means that one zone cannot request heating while the second simultaneously requests cooling.
The settings may differ, but the units must remain compatible with the selected mode.
This characteristic must be considered when the two spaces have very different exposures. Proper zone selection reduces conflict situations.
The connected capacity is not the simultaneous capacity
Fujitsu states that a multi-zone system can accept a connected capacity of up to 130 %, depending on the permitted configurations.
This does not mean that the outdoor unit will automatically provide the full sum of the rated BTUs of all the indoor units when they operate simultaneously.
When both zones require high capacity, the available output is distributed according to the outdoor unit’s limits.
Sizing must therefore take into account:
- the area of each zone;
- insulation;
- windows;
- sun exposure;
- air infiltration;
- the ceiling height;
- the outdoor temperature;
- the simultaneous use of the rooms;
- the actual low-temperature capacity.
Heating down to -26 °C for cold-climate versions
The Aquila series documentation indicates that CTEB versions designed for cold climates can operate in heating mode down to -26 °C.
This feature meets the winter conditions in Terrebonne. However, it is important to distinguish between the minimum operating temperature and the available capacity.
As with any heat pump, heat output may vary as the outdoor temperature decreases.
We must therefore check:
- low-temperature capacity;
- the home’s heat losses;
- the presence of a backup system;
- the insulation level;
- the design temperature;
- the actual needs of both zones.
A heat pump can significantly reduce the use of traditional electric heating, but the choice must be based on technical data and not solely on a displayed minimum temperature.
The technical steps that are not visible in the photo
The quality of an HVAC installation largely depends on steps that are invisible once the work is complete.
Leak testing
Each connection must be checked to confirm that it is not leaking refrigerant.
A small leak may take several months to cause a noticeable loss of performance.
Evacuation
The circuit must be evacuated to remove air and moisture. Insufficient evacuation can contaminate the oil and damage the compressor.
Calculating the additional charge
Depending on the total piping length, a precise amount of refrigerant may need to be added.
This quantity must be calculated according to the model’s instructions.
Testing both zones
We check the operation of each indoor unit, communication with the outdoor unit, heating, cooling, and drainage.
Mistakes to avoid when installing a wall-mounted unit
Attaching the bracket to non-load-bearing siding
The cladding brick must not be considered a sufficient structure without verification.
Installing the unit too low
Snow, plants, and defrost water may block the unit.
Neglecting vibrations
A rigid support without adequate insulation can transmit a humming noise indoors.
Allowing vegetation to overgrow the coil
Leaves and stems reduce airflow and trap debris.
Blocking the service panel
The unit must remain accessible for maintenance and repairs.
Choosing BTUs based solely on floor area
Glazing, insulation, floor level, and exposure significantly affect requirements.
Choosing two large indoor units without analyzing the outdoor unit’s capacity
Connected capacity does not guarantee equivalent simultaneous output.
Recommended maintenance for this installation
An outdoor wall-mounted heat pump should be inspected periodically.
Maintenance includes, among other things:
- cleaning the coil;
- removing leaves and debris;
- trimming the plants;
- checking the support;
- checking the fasteners;
- inspecting the pads;
- examining the line-set cover;
- checking the insulation;
- cleaning the indoor filters;
- drain inspection.
During winter, keep the area around the unit clear without striking the coil with a shovel.
Ice should not be removed with a sharp tool or an improvised heat source.
An AirGreen installation adapted to Terrebonne
This Fujitsu Aquila XLTH dual-zone heat pump installation in Terrebonne shows that a wall-mounted support can be an excellent solution when ground space is limited or already landscaped.
The unit is secured to a triangular structure anchored in the foundation. It remains clear of snow, plants, and defrost water. Pads help control vibrations, while the vertical line-set cover protects the connections and improves the finish.
The large front fan has sufficient clearance, and the service panels remain accessible.
At AirGreen, we install dual-zone heat pumps, multi-zone systems, and complete heating and air conditioning solutions in Terrebonne, Montréal, Laval, Longueuil, the North Shore, and the South Shore.
We analyze the wall structure, snow height, vegetation, piping route, the needs of each zone, and electrical capacity before determining the best configuration.
A quality heat pump must be paired with a sturdy support, precise sizing, and complete commissioning. This attention to detail enables the Fujitsu system to provide reliable operation, convenient access for maintenance, and comfort suited to both zones of the building.