Installation of a Fujitsu AIRSTAGE Altair 700 wall-mounted heat pump in Howick, Montérégie

A Fujitsu Altair 700 precisely installed in a room with a sloped ceiling in Howick

At Howick, we installed a Fujitsu AIRSTAGE Altair 700 wall-mounted heat pump in a room whose architecture imposed several interesting constraints: a sloped ceiling, a window occupying a large portion of the available wall, limited space above the opening, and a nearby ceiling fan.

This type of configuration is very different from a simple, completely unobstructed rectangular wall. Choosing the location of the indoor unit must take into account airflow, the clearances required around the unit, future access for HVAC maintenance, the building’s structure, and the unit’s visual integration into the room.

The photo taken during our work clearly shows the result: the Fujitsu AIRSTAGE indoor unit was positioned above the large window, in the vertical section of the wall, just before the ceiling slope. This location makes effective use of a space that would otherwise be difficult to use while keeping the floor and main walls clear for furnishings.

For our technicians, the challenge was therefore not simply to “install a heat pump.” They had to determine exactly where to install the unit so it could distribute air properly despite the room’s unusual geometry.

Why the location above the window made particularly good sense

In this room in Howick, the large window occupies almost the entire width of the wall. On the right, the ceiling slopes sharply, considerably reducing the available height. On the left, the ceiling fan and its sweep area also had to be taken into consideration.

We therefore used the available wall space above the window, where the unit can blow air directly into the living space.

This decision offers several advantages.

First, the unit remains relatively central in relation to the room. A wall-mounted heat pump works much better when its airflow can travel across a good portion of the space rather than being immediately blocked by a partition, cabinet, or sloped surface.

In addition, installing it above the window avoids sacrificing a wall that might be needed for a piece of furniture, a television, a bookcase, or storage.

Finally, in a room located beneath a roof or with sloped ceilings, heat buildup can be significant in summer. Warm air naturally rises toward the upper parts of the room. A wall-mounted unit installed high up can therefore operate directly in this area where heat tends to accumulate.

An installation that requires greater precision than a standard wall

A wall with a sloped ceiling leaves much less room for error.

If the unit had been installed a few inches too high, the clearance from the ceiling could have become insufficient. Too far to the right, the nearby slope could have impaired airflow and complicated access to the filter or housing. Too far to the left, the proximity of the fan would have required greater consideration.

We therefore sought a balance between:

• air circulation;
• the space above the unit;
• access for cleaning the filters;
• the ability to open the front panel properly;
• visual alignment with the window;
• the refrigerant piping route;
• condensate drainage;
• and the wall’s structural constraints.

The jobsite photograph also shows the actual installation environment: a professional step ladder, tools on the floor, and furniture protected during the work. These jobsite details remind us that a properly executed HVAC installation requires careful room preparation, especially when working in an already furnished space.

Fujitsu AIRSTAGE Altair 700: two capacities in this series

The Fujitsu documentation provided for this installation presents two single-zone systems from the Altair 700 series:

09KMAS1 – 9,000 BTU/h
12KMAS1 – 12,000 BTU/h

The corresponding sets are:

• ASUH09KMAS + AOUH09KMAS1 for the 9,000 BTU model;
• ASUH12KMAS + AOUH12KMAS1 for the 12,000 BTU model.

The interior photo does not make it possible to read the nameplate or determine with certainty which of the two capacities was used in this specific installation. We therefore prefer not to arbitrarily assign a capacity to the photographed unit.

What is certain, however, is that both models belong to the same Fujitsu AIRSTAGE Altair 700 platform, with Inverter technology, R-32 refrigerant, and several particularly appealing features in common for a residential installation.

Remarkable energy efficiency for a compact wall-mounted system

On the Fujitsu technical specifications sheet, the 9,000 BTU model has a SEER2 of 30.0, while the 12,000 BTU model reaches a SEER2 of 27.5.

These values are important when a homeowner compares several wall-mounted heat pumps in Howick, Montreal, Laval, Longueuil, on the North Shore, or on the South Shore.

SEER2 makes it possible to compare seasonal cooling efficiency. A high value means that the system can provide a great deal of cooling relative to the electricity consumed under the standardized conditions used for the assessment.

In heating mode, the documentation indicates an HSPF2 Region V of 9.9 for the 9,000 BTU model and 8.5 for the 12,000 BTU model. The rated COP2 is 4.64 and 4.32, respectively.

For the homeowner, the real benefit lies in the heat pump’s ability to continuously adjust its operation rather than operating only at full capacity.

Inverter technology suited to a room’s changing needs

The Fujitsu Altair 700 series uses an Inverter compressor.

When the room is very hot, the system can increase its output to quickly return to the requested temperature. Once it approaches the setpoint, it gradually reduces its capacity.

The difference is particularly noticeable in a bedroom, office, or room converted beneath a roof, like the one shown in the photo.

In this type of space, the heating and cooling load can change quickly. A large window can introduce significant solar heat during certain hours, while the proximity of the roof can raise the temperature even further in summer.

An Inverter heat pump can respond to these changes without constantly producing the same level of output.

A modulation range much broader than the rated capacity

The number of BTUs listed on a heat pump never tells the whole story.

According to the Fujitsu specifications, the 09KMAS1 has a rated cooling capacity of 9,000 BTU/h, but can modulate between 3,100 and 12,100 BTU/h.

In heating mode, its rated capacity reaches 12,000 BTU/h, with a range from 2,800 to 14,500 BTU/h.

The 12KMAS1, for its part, offers a rated cooling capacity of 12,000 BTU/h with a range of 3,100 to 13,800 BTU/h, as well as a rated heating capacity of 14,000 BTU/h that can modulate from 2,800 to 15,000 BTU/h.

This ability to operate at relatively low output is particularly interesting when heating needs are low.

An appliance that can continue operating gently can maintain a more consistent temperature while limiting on-off cycles.

Heating down to -15 °C

Fujitsu presents the Altair 700 as a system capable of operating in heating mode down to -15 °C, with an official heating range of -15 °C to 24 °C for both models.

In cooling mode, the specified operating range is -10 °C to 50 °C.

In an area like Howick, it is important to understand this figure correctly. A heat pump that can operate at -15 °C does not automatically mean it should be the sole source of heating for a residence throughout the entire cold season.

Sizing must take the entire building, insulation, heat loss, area served, and any supplementary heating into account.

At AirGreen, we always prefer to analyze the actual need rather than select a heat pump simply based on the number of square feet.

The technical details that really matter when installing a Fujitsu system in Howick

A very compact indoor unit despite its performance

The indoor unit of both Altair 700 models measures only:

• 32 13/16 in. wide;
• 10 5/8 in. high;
• 8 3/4 in. deep.

It weighs approximately 22 lb.

These compact dimensions are genuinely important in this installation.

With a steeply sloped ceiling and a relatively narrow strip of wall above the window, a much taller or bulkier indoor unit would have limited positioning options.

Here, the Altair 700’s design allows for a very clean integration into the room’s geometry.

The unit’s width also fits the available space well. Visually, it remains centered relative to the window without appearing disproportionate.

As low as 19 dB(A) indoors

In a room that could serve as a bedroom or resting area, sound level becomes particularly important.

Fujitsu indicates an indoor sound level as low as 19 dB(A) in cooling mode and 21 dB(A) in heating mode on quiet mode.

At low speed, the values are 30 and 33 dB(A). At medium speed, they reach 35 and 38 dB(A), while at high speed they are 40 and 42 dB(A).

This ability to operate very quietly is a practical advantage when installing a heat pump near a bed, a desk, or an area used in the evening.

Positioning in relation to the ceiling fan

The presence of a ceiling fan visible in the photo adds an interesting dimension to this installation.

A fan and a heat pump do not serve the same purpose.

The heat pump provides heating or cooling. The fan, on the other hand, essentially moves the air already present in the room.

When used intelligently, the two can complement each other. The fan can help redistribute air in a room with an irregular height or layout.

However, the indoor unit must not be positioned so that it blows directly into the fan blades at very close range. The airflow could then be unnecessarily disrupted.

The location selected here maintains a clear separation between the two units while allowing them to be used in the same room.

Precise refrigerant piping: 1/4 in. and 3/8 in.

The Fujitsu Altair 700 series uses the same piping dimensions for the 9,000 and 12,000 BTU models:

liquid line: 1/4 in.
gas line: 3/8 in.

Fujitsu specifies a minimum piping length of 10 feet, a maximum length of 66 feet, and a maximum vertical difference of 49 feet. The factory charge covers up to 49 feet.

These specifications are particularly important when replacing an old heat pump.

A common mistake is to automatically keep the old lines simply because they are already in place.

We always check:

• their diameter;
• their condition;
• their compatibility with the new unit;
• their length;
• the quality of their insulation;
• their routing;
• and the conditions required for an installation that complies with the manufacturer’s specifications.

A 15 A electrical circuit for both capacities

Another interesting feature of the series is that both systems operate at 208 to 230 V, 60 Hz, single-phase, with a 15 A circuit breaker according to the Fujitsu specifications.

The indicated maximum current reaches 6.4 A in cooling mode and 9.4 A in heating mode for the 9,000 BTU model, while the 12,000 BTU model reaches 6.9 A in cooling mode and 9.4 A in heating mode.

The electrical installation nevertheless remains something to verify on-site. We never assume that the existing circuit is correct simply because an old air conditioner or heat pump was already connected nearby.

R-32 and the new generation of wall-mounted heat pumps

The Altair 700 operates with R-32.

According to Fujitsu, this refrigerant has a global warming potential of 675, compared with 2,088 for R-410A, representing an announced reduction of 68% in GWP.

The transition to R-32 changes more than just a marking on the outdoor unit. It also requires appropriate practices during installation, commissioning, and future service work.

For a customer, the essential thing is to ensure that their installer understands the specific requirements of the equipment they are installing.

Built-in Wi-Fi to control the heat pump remotely

The Altair 700 series also features Wi-Fi connectivity, with remote monitoring through the AIRSTAGE mobile app. Fujitsu also offers several optional interfaces, including wired controllers and BACnet and Modbus integration options.

In residential use, Wi-Fi makes it possible to adjust the temperature remotely, change the settings before arriving home, and manage an upstairs room more easily.

For a property in Howick where a room beneath the roof can heat up quickly in summer, this feature can be particularly useful.

The importance of protecting the room during the work

The jobsite photo also shows something that technical specifications never mention: how a team works inside a property.

A wall-mounted installation may require drilling into the building, handling tools, and accessing an area near the ceiling.

In this room, the furniture was protected, and a drop cloth is visible on the floor during the work. The goal is simple: complete the installation cleanly while limiting dust, debris, and the risk of damage to existing surfaces as much as possible.

For us, this preparation is an integral part of the work.

The mistakes we avoid in a room with a sloped ceiling

A room like this can easily lead to several mistakes when an installation is planned too quickly.

Installing the unit too close to the slope can reduce the space around the appliance. Placing it too low can compromise its distribution efficiency and the wall’s appearance. Moving it too far to one side can create uneven airflow.

You should also avoid:

• to place the unit where a curtain could block the air intake or outlet;
• to make the filters difficult to remove;
• to neglect condensate drain flow;
• to create an excessively complicated piping route;
• to direct the airflow straight toward an occupied area at very close range;
• to consider appearance alone without taking operation into account.

The right location is always a compromise between architecture, comfort, technical accessibility, and performance.

An installation designed for years of service

The final photo of this Fujitsu installation in Howick shows a unit that appears naturally integrated into the room.

Yet this visual simplicity results from a series of technical decisions: height, available width, ceiling slope, window, fan, wall structure, route to the outside, and airflow direction.

That is exactly what we strive for at AirGreen.

A wall-mounted heat pump should not look as though it was installed wherever there happened to be space. Its placement should make sense.

In this Howick project, the Fujitsu AIRSTAGE Altair 700 occupies a section of wall that would otherwise be difficult to use while leaving the rest of the room available. At the same time, it benefits from an elevated position suited to air distribution, with relatively easy access for filter cleaning and maintenance.

A Fujitsu solution suited to residential projects in the Montérégie and Greater Montreal areas

This Howick installation clearly illustrates the type of project where choosing a compact, variable-capacity heat pump makes perfect sense.

The Fujitsu AIRSTAGE Altair 700 combines a compact indoor design, high seasonal efficiency ratings, R-32 refrigerant, Inverter technology, indoor operation as low as 19 dB(A), and built-in Wi-Fi.

But none of these features replaces a properly planned installation.

At AirGreen, we carry out heating, air conditioning, and wall-mounted heat pump projects in Howick as well as Montreal, Laval, Longueuil, the North Shore, and the South Shore. Every building presents different constraints, which is precisely why an on-site assessment is so important.

Whether in a traditional room, an attic bedroom, or a space beneath a roof, our goal remains the same: select the right capacity, find the best possible location, follow the manufacturer’s specifications, and carry out an installation that remains practical long after we leave.