In Elgin, a rooftop installation designed to protect the heat pump, facilitate defrosting, and preserve service access
For this project completed in Elgin, our AirGreen team had to install a Fujitsu AIRSTAGE Altair 700 wall-mounted heat pump in a configuration very different from a traditional installation on the side of a house. The outdoor unit had to be placed directly on a flat roof, near other mechanical and electrical equipment already in place.
The jobsite photograph immediately shows one of the most important aspects of the work: we did not simply place the heat pump on the roof covering. The Fujitsu outdoor unit is installed on a raised metal structure, which is itself supported by long pieces of wood that distribute the load across the roof.
This approach addresses several very practical objectives: lifting the unit off the roof, promoting the drainage of water from defrost cycles, reducing risks related to snow, preventing the heat pump’s base from remaining in moisture, and maintaining reasonable access to the components for future HVAC maintenance.
In Elgin, as with our installations in Montreal, Laval, Longueuil, on the North Shore and the South Shore, the final quality of an installation therefore depends not only on the choice of machine. The positioning of the outdoor unit, its support, piping management, and future accessibility directly affect the system’s lifespan and ease of maintenance.
A heat pump raised above the roof rather than placed directly on it
The photo of this project is particularly interesting because it clearly shows the support structure.
The outdoor unit rests on two metal crossbars attached to a vertical support. The machine’s four points of contact are well distributed, and the assembly is raised high enough to create clear space beneath the heat pump.
Under this structure, two long pieces of wood rest on the roof. Their role is not decorative: they help create a more stable base and distribute the support’s load over a larger surface rather than concentrating the entire weight of the heat pump on four small points.
For a rooftop heat pump installation, this consideration is important. A roof covering is not a concrete slab, and its construction must be taken into account before placing mechanical equipment on it.
Why clearance beneath the outdoor unit is particularly important in Quebec
A heat pump does not simply produce warm air inside the building. In heating mode, its outdoor unit must extract energy from the outdoor air. When certain temperature and humidity conditions occur, frost can form on the heat exchanger.
The machine then automatically initiates a defrost cycle.
During this process, water may flow beneath the outdoor unit. If the heat pump is installed too close to the roof or on a surface where water cannot drain properly, this water can gradually freeze around its base.
On this installation in Elgin, the elevation provides a much more favorable space beneath the unit.
This notably makes it possible to:
- to allow defrost water to drain more freely;
- to reduce the risk of ice reaching the base of the machine directly;
- to prevent normal snow accumulation from immediately surrounding the outdoor coil;
- to maintain better access beneath the unit;
- to separate the mechanical components from the roof surface.
For a homeowner comparing several HVAC installation quotes, the height and type of outdoor support are therefore details to examine, particularly when a heat pump must be installed on a flat roof.
A tight installation near other equipment
Another visible element in the image is the heat pump’s proximity to a mechanical structure located on the right-hand side.
The refrigerant and electrical connections are routed toward this area. This type of configuration requires a certain degree of precision: the unit must be close enough to allow the connections to be routed efficiently, but it must also maintain the clearances required for airflow and servicing.
We must also think about the person who will return to the roof in a few years to carry out an inspection, cleaning, or diagnosis.
A machine that is perfectly functional on the day of installation can become difficult to maintain if its access panels have been placed against an obstruction.
At AirGreen, we therefore try to maintain a serviceability mindset from the design stage of the installation.
The visible result: a clean, organized installation
The photo also allows several details of the completed work to be appreciated.
The outdoor unit is horizontal, its four feet are properly supported, and the lines are grouped on the same side rather than dispersed around the unit. The heat pump is not placed directly against the adjacent structure, and the side displaying the Fujitsu AIRSTAGE, R32, and AirGreen identifications remains unobstructed.
This type of result is particularly important for a rooftop installation, where improvised repairs and inadequate supports often become much more visible over the years.
Fujitsu AIRSTAGE Altair 700: a compact R-32 wall-mounted heat pump with efficiency reaching 30 SEER2
The Fujitsu AIRSTAGE Altair 700 belongs to Fujitsu’s single-zone H series. The technical documentation provided for this project covers two configurations: the 09KMAS1 and the 12KMAS1. They correspond respectively to nominal cooling capacities of 9,000 BTU/h and 12,000 BTU/h.
Since the complete number on the nameplate is not legible in the jobsite photograph, we cannot determine with certainty which of these two specific capacities applies to the photographed unit. This distinction is important when writing or analyzing the specifications of an actual installation: it is better to retain an accurate detail than to turn an assumption into a technical specification.
9,000 BTU or 12,000 BTU: two highly efficient configurations
The Fujitsu data sheet indicates for the version 09KMAS1 :
- nominal cooling capacity: 9,000 BTU/h;
- cooling modulation: 3,100 to 12,100 BTU/h;
- nominal heating capacity: 12,000 BTU/h;
- heating modulation: 2,800 to 14,500 BTU/h;
- SEER2 efficiency: 30.0;
- HSPF2 region V: 9.9;
- EER2: 16,4.
For the version 12KMAS1, Fujitsu indicates:
- nominal cooling capacity: 12,000 BTU/h;
- cooling modulation: 3,100 to 13,800 BTU/h;
- nominal heating capacity: 14,000 BTU/h;
- heating modulation: 2,800 to 15,000 BTU/h;
- SEER2 efficiency: 27.5;
- HSPF2 region V: 8.5;
- EER2: 13,5.
These figures clearly illustrate how an Inverter heat pump operates. The system is not limited to running at full capacity and then shutting down completely. It can adjust its operation according to the building’s actual load.
For the occupant, this can translate into a more stable temperature and less abrupt cycling than with some older equipment.
Heating down to -15 °C
The Altair 700 documentation indicates an operating range in heating mode of -15 °C to 24 °C for both models.
The cooling range extends from -10 °C to 50 °C.
In the case of an installation in Elgin, this data must be interpreted correctly. The fact that a heat pump can operate at -15 °C does not automatically mean that it will fully replace a building’s primary heating system under all conditions.
The result depends in particular on:
- the building’s heat loss;
- the level of insulation;
- airtightness;
- the amount of glazing;
- the floor area and interior layout;
- the heat pump’s exact capacity;
- whether or not a supplemental heating source is present.
That is why we place as much emphasis on heat pump sizing as we do on its brand.
R-32: the new generation used in this Altair 700
The logo R32 is clearly visible on the front of the outdoor unit photographed in Elgin.
Fujitsu states that R-32 has a global warming potential of 675, compared with 2,088 for R-410A, corresponding to an approximately 68% reduction in GWP according to the data presented in its documentation.
This development is important in the HVAC industry. Installation methods must nevertheless always comply with the procedures applicable to the type of refrigerant used, particularly for line preparation and system commissioning.
1/4 in. and 3/8 in. refrigerant connections
For an installer or homeowner preparing to replace a heat pump, piping size is essential information.
For both Fujitsu Altair 700 configurations presented in the document:
- liquid line: 1/4 po;
- gas line: 3/8 po.
Fujitsu also specifies:
- minimum piping length: 10 feet;
- maximum length: 66 feet;
- precharge up to 49 feet;
- maximum vertical difference: 49 feet.
These lengths make the series appealing for installations where the outdoor unit cannot be placed directly behind the indoor wall-mounted unit.
The Elgin project is a good example: when an outdoor unit has to be installed on a roof, the actual piping route can be much longer than a simple wall penetration.
A relatively modest electrical supply
Both models operate on:
208–230 V / 60 Hz / single-phase
and the documentation specifies a 15 A circuit breaker.
For the 09KMAS1 model, the maximum current is specified as 6.4 A in cooling and 9.4 A in heating.
For the 12KMAS1, it is 6.9 A in cooling and 9.4 A in heating.
These values are particularly useful when a homeowner replaces an old unit and wants to know whether the existing circuit might be suitable. However, the final verification must always be carried out based on the actual installation, the unit’s nameplate, and the building’s electrical configuration.
An outdoor unit weighing only 71 lb
An interesting feature of the Altair 700 series is its compact size.
The outdoor unit measures approximately:
- 31 7/16 in. wide;
- 21 5/16 in. high;
- 11 7/16 in. deep;
- net weight: 71 lb.
The indoor unit measures approximately 32 13/16 in. wide, 10 5/8 in. high, and 8 3/4 in. deep.
On a roof like the one seen in Elgin, this reduced depth greatly simplifies positioning between the various mechanical constraints.
Quiet operation: up to 19 dB(A) indoors
Sound level is often one of the most underestimated factors when choosing a wall-mounted air conditioner or heat pump.
In quiet mode, Fujitsu states an indoor sound level of just 19 dB(A) in cooling and 21 dB(A) in heating.
Outside, the 09KMAS1 is rated at 44 dB(A) in cooling and 47 dB(A) in heating. The 12KMAS1 is rated at 48 and 50 dB(A).
In a quiet area or when the unit is installed on a building where mechanical noise must remain discreet, these features can be genuinely important.
Built-in Wi-Fi and AIRSTAGE app
The Altair 700 series also offers built-in Wi-Fi connectivity for remote monitoring and control using the AIRSTAGE mobile app.
The owner can therefore adjust the temperature or check the system’s operation without being physically in front of the unit.
Fujitsu documentation also mentions various more advanced integration options, including wired controllers and interfaces compatible with BACnet, Modbus, or 24 V thermostats, depending on the accessories used.
For a home, these features may be optional. For a commercial building, apartment building, or site equipped with a centralized management system, they can become much more appealing.
ProCore coils and Inverter operation
Fujitsu also uses highly corrosion-resistant ProCore copper coils in the indoor unit of this series.
The manufacturer associates this design with improved component durability.
The system also includes several operating modes:
- economy mode;
- energy-saving mode;
- minimum heat mode;
- automatic defrost;
- automatic restart;
- wireless remote control;
- automatic adjustment of the vertical airflow direction.
Inverter technology allows the compressor to modulate its operation according to demand rather than using only complete on-off cycles.
An ENERGY STAR installation, but the subsidy must always be verified according to the exact model
The technical sheet classifies both 09KMAS1 and 12KMAS1 configurations in the ENERGY STAR categories indicated by Fujitsu.
For homeowners in Elgin and elsewhere in Quebec seeking a heat pump subsidy, it is nevertheless essential to verify the exact eligibility of the installed combination.
We never recommend relying solely on the trade name “Fujitsu Altair 700.”
Financial assistance programs generally use:
- the exact indoor and outdoor unit numbers;
- the certified combination;
- capacity;
- performance at certain temperatures;
- the program rules in effect at the time of installation.
A heat pump bearing the ENERGY STAR logo may meet certain criteria without automatically qualifying for the subsidy amount a homeowner saw in an advertisement.
What we would avoid in a comparable installation
This Elgin project also illustrates several mistakes we seek to avoid with rooftop-installed heat pumps.
A unit placed directly on the roof
This reduces clearance for defrost water, exposes the base to more moisture, and can make snow management problematic.
A support that is too low
A structure only a few inches high may seem sufficient in summer but become inadequate after several snowfalls.
A support installed without considering the roof
The weight of the equipment and its structure must be distributed properly. The support itself must not become a source of damage to the roof covering.
A unit placed against an obstacle
The compressor and outdoor coil need adequate airflow. Access to the service panels must also be maintained.
Connections left unorganized
The piping, communication cable, and electrical supply must follow a logical, protected route. A clean installation from the outset makes future servicing easier.
A small heat pump may require a highly technical installation
The image might give the impression of a relatively simple project: a single outdoor unit, a support, and a few lines.
In the field, a rooftop wall-mounted heat pump installation nevertheless requires many decisions.
The best location must be determined, the support prepared, the line route planned, the piping distances checked, the connections protected, the appropriate electrical connection completed, the refrigerant circuit evacuated, the machine commissioned, and its operation confirmed.
There is also the question of roof access and equipment handling.
Although this Fujitsu unit weighs approximately 71 lb, moving it to its final position without damaging the building or the equipment must be planned.
Why this Fujitsu Altair 700 installation in Elgin reflects our approach at AirGreen
We always seek to adapt the HVAC installation to the building rather than force the building to adapt to a standard method.
Here, the roof required a raised and stable solution. The Fujitsu Altair 700 heat pump, thanks to its compact design and Inverter operation, was well suited to this configuration.
The result is an installation where the outdoor unit remains accessible, clear of the roof, and properly positioned in relation to nearby equipment.
This attention to the outdoor structure is just as important as the performance specifications listed in the technical sheet.
A SEER2 rating of 27.5 or 30.0 is appealing, but the true quality of a project is also measured by what happens when the snow falls, when the machine defrosts, when the technician needs to access the service valves, or when the equipment operates after several years.
This is the approach we apply in our wall-mounted heat pump projects in Montreal, Laval, Longueuil, on the North Shore, the South Shore, and in Montérégie municipalities such as Elgin.
What a homeowner should ask before a similar installation
Before accepting a proposal for a heat pump installed on a roof, we recommend asking specifically:
- At what height will the outdoor unit be installed?
- How will the support rest on the roof?
- How will the defrost water be drained?
- What clearance will be left in front of and behind the unit?
- Will the service panel remain accessible?
- What will the total length of the refrigerant lines be?
- Does the proposed capacity actually match the building’s needs?
- What electrical circuit will be required?
- Is the exact model eligible for the rebates being sought?
- How will the lines be protected between the building and the unit?
These questions make it possible to compare not only heat pump prices, but also the quality of the proposed installation.
In this project in Elgin, the most visible part is this Fujitsu AIRSTAGE Altair 700, neatly installed on its support. The most important part, however, lies in all the technical decisions that made this result possible.