A multi-zone installation integrated into an already extensively landscaped backyard
In Saint-Bruno-de-Montarville, we installed a Fujitsu AIRSTAGE Aquila XLTH two-zone heat pump in a backyard where every square foot already had a specific purpose. The property featured a brick façade, a basement window, a spa installed near the building, a narrow service passage, and several recent improvements around the house.
The challenge was therefore not simply connecting two indoor units to one outdoor unit. It was necessary to plan an HVAC installation that respected traffic through the yard, access to the spa, the basement window, the masonry finish, and future maintenance needs.
The photograph shows the Fujitsu outdoor unit positioned to the left of the walkway, near the foundation wall. It is partially visible, since the image primarily highlights the finishing work completed on the façade. A long brown line-hide cover runs vertically along the brick, then descends and extends horizontally above the foundation. This routing protects the refrigerant lines, wiring, and communication components required for both zones.
The choice of brown was not accidental. It allows the line-hide cover to blend in with the brick, dark mortar joints, exterior accents, and wooden elements visible in the yard. In a multi-zone installation, the outdoor routing can be more substantial than that of a single-zone heat pump. A well-thought-out finish therefore makes a significant difference to the project's final appearance.
A two-zone heat pump for two spaces with different needs
The owner wanted to heat and cool two distinct areas of the house without installing two separate outdoor units. The Fujitsu Aquila XLTH two-zone heat pump makes it possible to connect two indoor units to a single outdoor unit.
Each zone can be controlled separately. This allows occupants to:
- set a different temperature in each room;
- turn off a zone when it is not in use;
- choose a fan speed suited to each space;
- adjust the airflow direction independently;
- program the units according to the family’s habits.
This configuration is particularly well suited when the two zones do not respond the same way to outdoor conditions. A room near the spa and backyard may receive more sunlight or be used more frequently, while another zone may be on a different level or in a shadier part of the house.
Fujitsu documentation indicates that H Series AIRSTAGE multi-zone systems can be combined with several types of indoor units, including wall-mounted units, slim duct units, compact cassettes, and certain concealed duct units. It also states that each indoor unit can be controlled independently, although the zones must operate in the same general heating or cooling mode.
In other words, the two zones can be set to different temperatures, but one unit cannot provide heating while the other simultaneously calls for cooling.
The presence of the spa influenced the entire outdoor planning process
The spa visible at the back of the yard is installed close to the building. This layout created several constraints.
We had to preserve:
- enough space to move between the house and the spa;
- convenient access to the steps;
- a safe area for future work;
- adequate clearance around the outdoor unit;
- a line route that does not unnecessarily cross areas in use;
- access to the heat pump’s service panel.
Installing the outdoor unit directly in front of the spa or along the main path would have interfered with use of the yard. We also had to avoid directing the fan airflow toward an area where occupants regularly walk when getting out of the water.
Moisture around a spa is another consideration. The heat pump must remain accessible and must not be placed where splashed water or spa maintenance activities could directly reach the electrical components.
The selected placement keeps the unit close to the building while leaving the center of the yard relatively open.
A basement window to preserve
A basement window is visible in the foundation, just below the horizontal run of the line-set cover. This opening had to remain accessible and functional.
We therefore avoided:
- to place the unit directly in front of the window;
- to route the lines through the middle of the opening;
- to block access in case replacement is needed;
- unnecessarily reducing natural light;
- creating an obstacle to drainage around the window well.
During a heat pump installation, small basement windows are sometimes considered secondary. However, depending on their configuration, they can provide light, ventilation, access, or an escape route.
The line-set cover was positioned above the window, with a horizontal route following the foundation line. This method protects the lines without encroaching on the opening.
A vertical-then-horizontal route adapted to the structure of the house
The photograph shows a long vertical section that rises almost to the soffit, followed by a horizontal section that returns toward the outdoor unit.
In a dual-zone system, this configuration may be necessary when the indoor units are located at different heights or in separate rooms. Both refrigerant circuits must originate at the outdoor unit and then be routed to the selected indoor locations.
The exterior route generally contains:
- two pairs of refrigerant lines;
- the insulation around each line;
- communication cables;
- the conductors required by the system;
- condensate drains, depending on the configuration;
- transition fittings.
We aim to limit the number of elbows because each change in direction complicates the installation and increases the overall footprint. In this project, the main route follows simple architectural lines: a vertical rise, a change in direction, and a horizontal section parallel to the foundation.
This arrangement also makes future inspections easier. Technicians can visually follow the route without having to guess where the lines run.
Why the color of the line-set cover matters
A white line-set cover would have created a strong contrast against the red and brown brick. Instead, we used a dark shade that complements the colors already present on the house.
The line-set cover protects the components from:
- ultraviolet rays;
- rain;
- snow;
- freezing;
- impacts;
- animals;
- gardening work;
- movement around the yard.
A well-chosen exterior finish therefore improves both the system’s durability and its appearance.
A ground-level installation that requires careful clearance management
The outdoor unit visible on the left appears to be installed near the foundation and close to the basement window. Although it is not fully in frame, its location indicates that the available space was limited.
We needed to maintain sufficient clearances for:
- air intake;
- air discharge through the fan;
- opening the panels;
- access to the connections;
- cleaning the heat exchanger;
- drainage of defrost water;
- snow removal.
A heat pump placed too close to a wall or landscaping can recirculate some of the air it has just expelled. This phenomenon reduces performance, especially during periods of high demand.
The ground around the unit must also remain stable. The photo shows landscaping work in progress, gravel, and areas that are still open. We ensure that the heat pump's base will not be compromised by future work.
Coordination with the outdoor improvement work
The stepladder, hose reel, shovel, gravel, and concrete blocks visible in the photo indicate that the yard was still being transformed during the project.
This context requires special coordination. A heat pump installed before the outdoor work is completed may be exposed to:
- impacts caused by tools;
- dust;
- movement of materials;
- changes in ground level;
- work near the lines;
- damage to the covers;
- a temporary obstruction of the fan.
We must therefore determine the final location while considering how the yard will look after the work. A base installed at the right level today could end up too low if paving or fill is added later.
We are also discussing with the owner of the space that will need to remain clear around the unit once the improvements are completed.
The Fujitsu Aquila XLTH: a multi-zone option that must be precisely validated
AIRSTAGE H-series configurations
According to Fujitsu documentation, H-series multi-zone outdoor units are available in nominal capacities of 18,000, 24,000, 36,000, and 45,000 BTU/h. Depending on the model and authorized combinations, they can power up to two, three, four, or five indoor units, respectively.
For a two-zone configuration, the manufacturer's table includes the following combinations:
- 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.
These combinations indicate that the indoor units can be connected together. However, they do not by themselves determine whether the configuration is suitable for the building.
The exact capacity of the photographed unit cannot be read with sufficient precision. We therefore do not estimate it based on the size of the outdoor cabinet.
Why load calculations remain essential
Two homes of similar size may require very different capacities. In Saint-Bruno, we must consider several factors before choosing the indoor and outdoor units:
- wall insulation;
- attic insulation;
- number of windows;
- solar orientation;
- ceiling height;
- actual open area;
- presence of a basement;
- air infiltration;
- use of each zone;
- low-temperature capacity;
- total piping length;
- height difference between the units.
A rule based solely on square footage can lead to a poor choice. An oversized unit may short-cycle and dehumidify less effectively. An undersized unit may run continuously without maintaining the desired temperature.
Fujitsu specifies in its documentation that its combination tables do not replace capacity selection and recommends using the Design Simulator software to properly select equipment for H series AIRSTAGE systems.
Connection capacity is not output capacity
The manufacturer allows certain combinations in which the sum of the indoor units’ rated capacities exceeds the outdoor unit’s rated capacity.
The documentation mentions a connection capacity of up to 130%, but specifies that exceeding 100% does not increase the outdoor unit’s output.
When both zones operate at full demand, the available capacity is divided between them. It is therefore necessary to assess the likelihood that both spaces will need their maximum capacity at the same time.
For example, two rooms with significant sun exposure may place a heavy demand on the system during a heat wave. Conversely, a bedroom used at night and a living area used mainly during the day may have less simultaneous demand.
Low-temperature operation
The Aquila range includes versions designed for cold climates. The documentation states that CTEB units can operate in heating mode down to -26 °C. It also mentions an inverter compressor, protection functions for the circuit, fan motor, and compressor, as well as a heat exchanger designed to offer improved corrosion resistance.
The variable-speed compressor adjusts its output to match demand. When demand is low, it can operate at a reduced speed instead of constantly starting and stopping.
This modulation contributes to:
- stabilize the temperature;
- reduce comfort differences;
- adjust consumption;
- distribute capacity among the zones;
- limit short cycling;
- improve operation during intermediate periods.
However, it should be remembered that heating capacity changes as the outdoor temperature drops. The fact that a unit operates at -26 °C does not mean that it provides exactly the same capacity as it does at 0 °C.
The importance of line length in this project
The long visible run along the wall shows that the lines had to cover a considerable distance to reach the indoor units.
The total length affects:
- system selection;
- the refrigerant charge;
- capacity losses;
- the commissioning time;
- the line layout;
- the allowable height difference.
We verify the manufacturer's limits before installation. If the lines exceed the precharged length, additional refrigerant may be required according to the technical data for the exact model.
A multi-zone installation also includes several circuits. It is essential to identify each line to avoid reversing the electrical and refrigeration connections.
The refrigerant and connection quality
The recent Fujitsu range featured in this installation uses the refrigerant R32, as indicated by the label visible on the units in this series.
R32 requires appropriate work methods. We perform, among other things:
- cleanly cutting the lines;
- flaring with a suitable tool;
- tightening to the recommended torque;
- a pressure test;
- a leak search;
- a measured vacuum pull-down;
- charge verification;
- a test in both modes.
The connections are one of the most sensitive points in an installation. A slow leak may not produce any immediate symptoms but can gradually reduce performance.
Condensate management in both zones
Each indoor unit produces water in cooling mode. This water must be drained reliably.
In a dual-zone installation, we must plan for two independent drains or a configuration compatible with the selected routing.
The drains must:
- maintain a slope;
- avoid back-pitches;
- remain accessible;
- be protected against obstructions;
- not discharge water in a problematic location;
- avoid high-traffic areas;
- not create dangerous ice during the cold season.
The presence of the spa and rear steps made choosing the discharge point particularly important. Water could not flow onto a step or into a passage used by the occupants.
Mistakes to Avoid in a Landscaped Yard
Positioning the heat pump without considering the spa
Airflow, panel access, and moisture must be assessed.
Blocking a basement window
Light, access, and drainage must be preserved.
Installing the line-hide without considering the aesthetics
A long vertical section becomes a permanent feature of the façade.
Forgetting about future paving work
The ground level may change and reduce the available clearance beneath the unit.
Leaving the lines exposed
Outdoor insulation deteriorates quickly without protection.
Directing drainage toward the steps
Water can create slippery surfaces or ice buildup.
Neglecting service space
Even in a tight yard, the panels and valves must remain accessible.
Our Commissioning Procedure
Before handing the system over to the customer, we carry out a series of checks:
- inspection of the outdoor unit’s base and stability;
- clearance check;
- line-set route check;
- inspection of the line-hide fasteners;
- pressure test;
- leak detection;
- vacuuming the system;
- electrical connection check;
- identification of each circuit;
- first-zone test;
- second-zone test;
- simultaneous operation of both units;
- drain inspection;
- heating check;
- air conditioning check;
- an explanation of the controls to the homeowner.
We then remove the materials and tools from the passageway to leave the yard clean and safe.
An Installation Adapted to Saint-Bruno and the South Shore
This project in Saint-Bruno-de-Montarville shows that a successful installation must take the entire property into account, not just the equipment.
The spa, steps, basement window, brick, foundation, and landscaping work all influenced our decisions.
The project’s key features include:
- a single outdoor unit for two zones;
- a protected line-set route;
- a brown line-hide matching the façade;
- a basement window left unobstructed;
- integration compatible with the spa;
- maintained access for maintenance;
- planning adapted to the exterior work;
- a Fujitsu configuration selected according to the building’s needs.
At AirGreen, we carry out installations of dual-zone heat pumps in Saint-Bruno, Longueuil, and the South Shore, as well as in Montreal, Laval, and the North Shore. We adapt each installation to the structure, outdoor layout, heating and cooling needs, and the manufacturer’s technical requirements.