A wall-mounted outdoor installation designed to preserve the yard, windows, and access around the house
This Fujitsu AIRSTAGE Aquila XLTH dual-zone heat pump installation in Sainte-Marthe-sur-le-Lac illustrates a very common situation in residential properties on the North Shore: outdoor space is available, but every square foot counts. The homeowner wanted to improve comfort in two distinct areas of the house without adding multiple outdoor units, while keeping a clear passage along the building and protecting the basement openings.
The photograph shows a Fujitsu outdoor unit installed on a reinforced wall bracket, above ground level and slightly offset from a basement window. An outdoor electrical disconnect remains accessible on the right. The refrigerant lines and wiring were grouped inside a vertical cover running up along the brick wall, protecting the connections while maintaining a neat appearance.
The project required precise coordination of the condenser’s position, the mounting height, technical clearances, line routing, and future access for maintenance. The result is a clean, compact HVAC installation suited to Quebec winters.
Why a dual-zone system was suitable for this home
A dual-zone heat pump connects two indoor units to a single outdoor unit. This solution is particularly suitable for homes where two areas have different heating or cooling needs.
In Sainte-Marthe-sur-le-Lac, several residential layouts can benefit from a multi-zone system:
- a ground floor and a finished basement;
- an upper floor and a living area;
- a primary bedroom located far from the living room;
- an extension added to the house;
- two areas separated by several walls;
- an open-concept area and a more enclosed room.
The main benefit is being able to control each indoor unit separately. Occupants can set a different temperature in each zone and adjust operation based on the actual use of the rooms.
Fujitsu documentation nevertheless specifies that the indoor units share the same outdoor unit. They can heat or cool, but they cannot operate simultaneously in opposite modes.
This means that one zone can be set to 20 °C and the other to 22 °C in heating mode, but it is not possible to heat one room while the other requests cooling.
An outdoor location chosen to avoid conflicts with the windows
The outdoor unit is installed between two sensitive areas: a basement window below and another opening located farther along the foundation.
A heat pump placed too close to a window can create several difficulties:
- more noticeable noise indoors;
- partial obstruction of the opening;
- limited access for cleaning;
- snow accumulation in front of the window;
- difficulty opening or replacing the window sash;
- air recirculation if the space is too restricted.
In this project, we placed the condenser above and slightly to the side of the lower window, preserving the light, access, and function of the opening.
The wall-mounted support also completely frees up the ground beneath the unit. The homeowners can continue maintaining the lawn, flower beds, and plants without having to work around a slab on the ground.
Why a wall-mounted support was particularly appropriate
The choice of a wall-mounted support depends on several factors: the wall structure, the unit’s weight, the desired height, the stability of the foundation, and vibration risks.
In this installation, the wall-mounted support offered several advantages:
- Protection from snow: the unit is elevated above the ground.
- Clearance beneath the condenser: defrost water can drain away without immediately becoming trapped in ice.
- Preservation of the landscaping: no large slab occupies the ground.
- Easier access to the window: the heat pump base does not block the opening.
- Easier yard maintenance: mowing and cleaning remain possible beneath the unit.
- Reduced movement caused by frost heaving: the condenser does not rest directly on a slab that could shift.
The support was secured in an appropriate area of the foundation to bear the weight of the outdoor unit. Diagonal braces are visible beneath the horizontal arms, improving the stability of the assembly.
Anti-vibration pads between the unit and the support
The photograph also shows pads beneath the condenser’s feet. These components help reduce the transmission of vibrations to the metal structure and the building.
This precaution is particularly important when the unit is installed near:
- a bedroom;
- an office;
- a living room;
- a basement window;
- a dense masonry wall.
A variable-speed compressor heat pump can operate at different speeds. At certain speeds, an installation that is too rigid or improperly leveled could amplify certain vibrations.
The pads do not replace secure fastening or proper leveling, but they complement the installation and contribute to acoustic comfort.
Completely unobstructed airflow at the front
The outdoor unit’s fan blows toward the side yard. No nearby wall, railing, or shrub directly blocks the grille.
This clearance is essential. A heat pump must draw air through its heat exchanger and expel it toward the front. If the discharged hot or cold air immediately returns toward the unit, performance may decrease.
We therefore check:
- the space in front of the fan;
- the distance from adjacent walls;
- the presence of fences;
- the proximity of vegetation;
- areas where snow can accumulate;
- permanent or seasonal obstacles.
In this case, the side passage remains open enough to allow adequate airflow.
The proximity of the balcony and railing
On the right side of the photograph, a balcony or deck structure with a railing can be seen. The outdoor unit had to be positioned so that it would not blow directly toward the occupied area or obstruct passage.
The condenser is located far enough from the structure to avoid an immediate conflict with the railing. The service panel also remains accessible from the side of the unit.
This accessibility is important for:
- inspections;
- electrical testing;
- pressure checks;
- cleaning the heat exchanger;
- future repairs;
- the replacement of components.
An installation may operate properly on the day it is commissioned, but become very costly to maintain if the service panel is blocked by a deck, fence, or outdoor furniture.
An accessible, clearly positioned electrical disconnect switch
The disconnect switch visible to the right of the unit makes it possible to cut power to the condenser during maintenance or service.
Its location must be:
- visible;
- accessible;
- protected against impacts;
- installed at an appropriate height;
- near the equipment without obstructing the lines.
In this project, the disconnect switch is located on the brick wall, at a convenient distance from the outdoor unit. The electrical conduit is neatly secured along the foundation and runs up to the enclosure.
This arrangement makes the technicians’ work easier and limits exposed cables.
A vertical line cover to protect the pipes
The refrigerant lines and cables are grouped inside a line cover that runs up along the façade. This solution offers several advantages.
It protects the components from:
- UV rays;
- impacts;
- the elements;
- small animals;
- friction;
- debris;
- accidental handling.
It also improves the installation’s appearance by avoiding several loose pipes against the wall.
Choosing a vertical route makes it possible to reach the indoor units located higher in the house without adding unnecessary detours.
Passing through a brick wall
Drilling through a brick wall requires careful planning. The penetration point must allow a logical route to the indoor unit while avoiding structural elements and obstacles within the cavity.
The penetration must then be properly sealed to limit:
- water infiltration;
- air loss;
- insect entry;
- moisture risks;
- pipe movement.
In a home on the North Shore, freeze-thaw cycles can worsen sealing defects. A durable finish around wall penetrations is therefore essential.
The Fujitsu Aquila XLTH system specifications and the technical decisions behind this installation
A multi-zone range with several outdoor-unit capacities
Fujitsu documentation lists 18,000, 24,000, 36,000, and 45,000 BTU/h outdoor units for H-Series AIRSTAGE Aquila systems. Depending on the model, these units can power two to five indoor units.
In a two-zone installation, the two-port condenser can be paired with wall-mounted units of several capacities.
The Fujitsu table shows the following combinations in particular:
- 7,000 + 7,000 BTU;
- 7,000 + 9,000 BTU;
- 7,000 + 12,000 BTU;
- 7,000 + 15,000 BTU;
- 9,000 + 9,000 BTU;
- 9,000 + 12,000 BTU;
- 9,000 + 15,000 BTU;
- 12,000 + 12,000 BTU.
These values confirm the units’ compatibility, but they do not replace a load calculation.
Fujitsu states that its combination tables should not be used alone to select a system’s capacity. Instead, the manufacturer recommends using its design tool to validate AIRSTAGE equipment.
Why the exact BTU rating should not be assumed from a photograph
The photograph confirms that this is a Fujitsu AIRSTAGE outdoor unit, but it does not allow the model number or capacity to be read with certainty.
Several condensers may have similar dimensions. To confirm the BTU rating, you must consult:
- the nameplate;
- the quote;
- the invoice;
- the installation file;
- the indoor unit models;
- the combination approved by Fujitsu.
At AirGreen, we avoid assigning a specific capacity without documentary evidence.
Separate sizing of the two zones
Each zone must be assessed individually.
We consider, among other factors:
- floor area;
- volume;
- the number of exterior walls;
- insulation;
- the windows;
- solar orientation;
- the presence of doors;
- the floor;
- the room’s use;
- heat loss;
- heat gains in summer.
A small bedroom does not have the same requirements as an open-concept area. Installing the same capacity in both zones is therefore not always logical.
An oversized unit may quickly reach the desired temperature without running long enough to properly dehumidify in summer.
An undersized unit may run continuously without reaching the setpoint during the hottest days or coldest nights.
Cold-climate operation
The Aquila series documentation specifies that CTEB versions can operate in heating mode down to -26 °C and in cooling mode up to 50 °C.
This feature is particularly important in Sainte-Marthe-sur-le-Lac, where winters can be cold and windy.
However, it is important to distinguish between the minimum operating temperature and the actual capacity available at that temperature.
A heat pump can continue heating at very low temperatures, but its output may vary depending on:
- the exact model;
- the demand from both zones;
- the length of the lines;
- defrost cycles;
- the outdoor temperature;
- the home’s heat loss.
The supplemental heating system therefore remains an important part of the overall strategy, depending on the building’s characteristics.
The inverter compressor
Fujitsu indicates that its multi-zone systems use a variable-speed compressor.
This technology allows the condenser to adjust its output when:
- only one zone is operating;
- both zones require little capacity;
- a zone reaches its setpoint;
- the outdoor temperature changes;
- demand increases rapidly.
This modulation limits sudden temperature fluctuations and generally improves comfort compared with a strictly on-off system.
A connection capacity of up to 130%
Fujitsu documentation mentions a connection capacity of up to 130 %, depending on the outdoor unit and the selected combination. However, it specifies that exceeding 100% does not increase the condenser’s actual production capacity.
This distinction is essential.
If the indoor units have a combined capacity greater than that of the outdoor unit, the system does not automatically produce more. When both zones call for maximum capacity at the same time, the available capacity is distributed.
Such a combination may be appropriate if the two zones do not reach their maximum load simultaneously. It may also create a comfort limitation if demand is high at the same time.
Sizing must therefore be based on the actual loads, not solely on the stated nominal capacities.
The two zones can be adjusted separately
Each indoor unit can have:
- its own temperature;
- its own fan speed;
- its own schedule;
- its own operating level.
However, the two zones share the same primary mode.
For example:
- both can heat with different setpoints;
- both can cool with different setpoints;
- one zone can be turned off while the other operates;
- they cannot operate in heating and cooling mode simultaneously.
This rule must be understood to avoid conflicts between the controls.
Defrosting and managing water beneath the unit
In heating mode, frost may form on the outdoor coil. The system then initiates a defrost cycle.
During this cycle, water drains beneath the unit. The wall bracket creates enough space for this water to fall to the ground without immediately accumulating against the base of the condenser.
However, the owner must monitor ice formation beneath the unit in winter.
We recommend:
- keep the area beneath the unit clear;
- remove excessive buildup;
- avoid breaking ice with a tool near the lines;
- do not pour hot water on the coil;
- never cover the heat pump completely;
- keep the front of the fan clear.
Nearby plants
Plants are visible at the base of the wall. They do not block the outdoor unit, but their growth should be monitored.
Plants can become problematic if they reach:
- the rear coil;
- the service panel;
- the lines;
- the underside of the bracket;
- the fan grille.
A reasonable size helps preserve access and prevent leaves or stems from accumulating around the unit.
Mistakes to avoid in a similar installation
This project highlights several common mistakes:
- Installing the condenser directly in front of a window.
- Installing a wall bracket in an unsuitable section.
- Neglecting diagonal bracing.
- Installing the unit too low for winter.
- Reducing the clearance in front of the fan.
- Blocking the service panel.
- Leaving the lines unprotected.
- Placing the disconnect in a difficult-to-access area.
- Choosing the capacity based solely on the floor area.
- Using a combination not approved by Fujitsu.
- Neglecting the slope of the indoor drainage.
- Planting shrubs too close to the heat exchanger.
Future maintenance of the outdoor unit
The wall bracket makes several maintenance tasks easier. The underside of the unit is visible, the side panel remains accessible, and vegetation can be maintained around the foundation.
Periodic maintenance may include:
- cleaning the heat exchanger;
- inspection of the supports;
- checking the bushings;
- inspection of the line insulation;
- checking the electrical connections;
- debris removal;
- checking the defrost drainage;
- inspection of the disconnect.
The owner should also monitor unusual noises, vibrations, and ice accumulation.
An AirGreen installation adapted to the home and property
This project in Sainte-Marthe-sur-le-Lac shows that a multi-zone system must be integrated into the building as a whole, rather than installed according to a one-size-fits-all formula.
We had to take into account:
- the brick wall;
- the foundation;
- the basement window;
- the balcony;
- the side passage;
- the landscaping;
- the technical clearances;
- the line routing;
- the electrical power supply;
- winter conditions.
The wall bracket preserved the property and protected the unit from snow accumulation. The vertical line cover organizes the lines neatly. The disconnect remains accessible, and the fan blows toward an unobstructed area.
At AirGreen, we apply the same level of care to our installations of heat pumps, wall-mounted air conditioners, and multi-zone systems in Montreal, Laval, Longueuil, on the North Shore, and on the South Shore.
This Fujitsu AIRSTAGE Aquila XLTH dual-zone heat pump now provides independent control in two areas of the home, with a single outdoor unit that is well integrated into the building.
The quality of an installation is evident in the details: condenser height, clearances, accessibility, line protection, support strength, and validation of the technical combination. These decisions are what allow the system to operate reliably over the long term in Quebec’s real-world conditions.