When the best location for a heat pump is precisely where the wall already appears to be occupied
On this project carried out in the Saint-Louis, one of the system's three indoor units GREE FREEMATCH R32 had to be integrated into a room where almost every section of wall already served a purpose. An exterior door occupies the center of the wall, a large window with blinds is immediately to the left, shelves are installed on the right, and a tall piece of furniture uses the lower part of the same wall.
The solution chosen by our AirGreen team was to make use of the available space directly above the door.
The photo taken after the installation shows a GREE wall-mounted unit well integrated into this upper area. The lower flap is open and the digital display indicates 21. This value may correspond to the setpoint or to a temperature reading, depending on the display mode; the photo alone does not make it possible to confirm which one. What is clear, however, is that the unit is powered on and operating.
This placement appears natural once the installation is complete. However, installing an indoor unit above a door requires more careful preparation than mounting it on a large, completely unobstructed wall. We must simultaneously account for the structure above the opening, air intake, drainage, piping routes, air distribution, and future access for maintenance.
A compact room where a poorly positioned wall-mounted unit would quickly have become an obstruction
The photograph makes the site constraint immediately clear.
The lower part of the wall could hardly accommodate a heat pump:
- the exterior door occupies the central area;
- the window with blinds uses the left-hand section;
- some wall-mounted shelves limit the space on the right;
- a tall piece of furniture or equipment also occupies this area;
- a desk chair visible in the foreground indicates that part of the room is used as a workspace or activity area.
In this type of configuration, installing the head on an adjacent wall solely to simplify the work could affect comfort. The airflow could be directed straight at the occupant, the head could become visually dominant, or the installation could require a long line set cover running across a significant part of the room.
We therefore used the available height.
This approach offers a concrete advantage: the heat pump takes up virtually no usable wall space.
Why the space above a door can be useful for an indoor unit
A wall-mounted unit works by drawing in room air through the upper section, then passing it through its heat exchanger before blowing it out through the lower flap.
By positioning it above the door, we can achieve several benefits when the room’s geometry allows it:
- keep walls intended for furniture clear;
- position the unit away from contact areas;
- encourage airflow along the length of the room;
- reduce the risk of furniture blocking the airflow;
- achieve a discreet visual integration;
- keep the windows fully available.
However, this configuration should not be confused with a genuine air curtain commercial. The GREE indoor unit is not installed to create a permanent air curtain above the door. Its role remains to heat or cool the entire area.
An exterior door and a window create specific heating and cooling requirements
The position of this indoor unit is also interesting because the portion of the building visible in the photo includes two surfaces that can strongly affect the heating and cooling load: a door leading outside and a window.
In winter, heat loss can be greater near:
- the glazing;
- the window frame;
- the door;
- the perimeter seals;
- the threshold.
In summer, solar gains through a window can quickly increase the temperature in that part of the room.
This does not mean that a heat pump must always be installed above a door or window. Above all, we must assess the overall air circulation and avoid leaving any area inadequately served.
On this project, the location allows the indoor unit to be positioned in a peripheral part of the room while maintaining a clear airflow zone in front of it.
The space between the ceiling and the unit must remain functional
The photo also shows that the indoor unit is installed relatively close to the ceiling without being completely flush against it.
This overhead space is important.
The unit must be able to draw in enough air. We must also maintain the necessary access to open the front panel and remove the filters.
An installation that is too close to the ceiling can lead to:
- less favorable air return;
- difficult access to the filters;
- more complex maintenance work;
- faster dust buildup in an inaccessible area.
During our HVAC installation, so we check not only whether the indoor unit physically fits in the available space, but also whether it can be used and maintained normally for years after we leave.
Installing above a door requires understanding what lies behind the wall
A door normally has a reinforcing structure around its opening. Before drilling, we must identify the wall’s composition and choose an appropriate route for the lines.
A wall-mounted heat pump requires several components:
- two refrigerant lines;
- a communication and power cable, depending on the configuration;
- a condensate drain;
- the insulation around the lines.
We therefore never choose the drilling point solely by looking at the drywall surface.
The following must be taken into account:
- structural elements;
- electrical wires;
- studs;
- obstacles in the cavity;
- the outdoor route;
- the slope required for the drain.
The goal is to route the connections without unnecessarily weakening the structure surrounding the door and without imposing excessive bends on the copper tubing.
A finish with no line set cover cluttering the visible section of the wall
In the photograph, no line set cover descends below the head or beside the door.
We cannot determine from the image alone the complete route used behind the unit, but the visible portion of the installation remains particularly clean.
This matters in a small room.
A vertical line set cover several feet long can perform its technical function perfectly well, but it becomes a significant visual element when it is located above a central door.
When a more discreet route is possible without compromising drainage or access to the connections, we favor it.
The GREE FREEMATCH R32: a single outdoor unit for three zones
The head visible in Saint Louis is part of a three-head heat pump. It is therefore not an independent wall-mounted air conditioner.
The principle GREE FREEMATCH R32 involves connecting several indoor units to a single outdoor unit.
For occupants, this makes it possible to create three comfort zones. Each can have:
- its own set temperature;
- its own fan speed;
- its own on-off operation according to the zone’s needs.
However, the three heads share the same outdoor compressor.
This distinction is essential when sizing the system: the BTU ratings listed for the three indoor units should not simply be added together to assume the capacity available simultaneously.
A multi-zone platform offering up to 21 SEER2
According to the technical sheet for the GREE FREEMATCH R32, the range offers efficiency of up to 21 SEER2, 12.5 EER2 and 10 HSPF2. The documentation also indicates an operating range from -30 °C to 48 °C in cooling mode and -30 °C to 24 °C in heating mode, with a total piping length of up to 100 m in the largest configuration.
Page 1 also presents several features suited to a multi-zone installation:
- inverter technology G10;
- intelligent defrosting;
- self-diagnostics;
- automatic voltage adaptation;
- quiet operation;
- indoor units powered by the outdoor unit;
- up to seven different indoor unit options;
- A2L leak detection sensor included.
Inverter modulation is particularly relevant in a three-head system. When only one zone requires a minor temperature adjustment, the compressor does not necessarily need to operate as it would when high demand comes simultaneously from all three rooms.
Which FREEMATCH R32 capacities can power three heads?
The technical table on page 2 lists five outdoor units, but the 18,000 BTU/h model is limited to two indoor units.
For three heads, the options shown are:
| GREE outdoor unit | Number of indoor units | Rated cooling | Rated heating |
|---|---|---|---|
| GWHD(24)ND6MO | 2 to 3 | 24,000 BTU/h | 24,000 BTU/h |
| GWHD(30)ND6MO | 2 to 4 | 28,400 BTU/h | 30,000 BTU/h |
| GWHD(36)ND6MO | 2 to 4 | 36,000 BTU/h | 36,000 BTU/h |
| GWHD(42)ND6MO | 2 to 5 | 42,000 BTU/h | 44,300 BTU/h |
These outdoor units operate on a power supply of 208/230 V.
The photograph from Saint Louis shows only one of the wall-mounted units and does not reliably identify the exact outdoor unit model or the number of BTUs assigned to this head. We therefore do not turn a visual estimate into technical data.
Why three identical heads are not always the right solution
A good multi-zone design begins with analyzing each room.
We consider, in particular:
- floor area;
- actual air volume;
- insulation quality;
- number of windows;
- presence of an exterior door;
- solar orientation;
- floor;
- electrical equipment present;
- room use;
- occupancy frequency.
At the site shown here, the presence of a door and a window on the same wall is a factor to include in the calculation.
Another area of the building could have completely different conditions. Therefore, it would make little sense to automatically require three heads of identical capacity.
From the indoor unit above the door to the outdoor unit: the technical details that determine system quality
Three zones mean three properly identified circuits
The outdoor unit must know which indoor unit it is communicating with.
Each zone has its own refrigerant lines and connections. During installation, we methodically identify the circuits so that the refrigerant port and wiring correspond to the same indoor unit.
This step may seem elementary, but it becomes critical with multiple zones.
A reversal can cause inconsistent operation and significantly complicate troubleshooting when the lines have already been covered by their protective coverings.
The line diameters and lengths specified for the product range
The manufacturer's data sheet indicates a diameter of 1/4 in. for the liquid line and 3/8 in. for the gas line for the models shown.
For outdoor units capable of powering three heads, the indicated maximum total length varies by capacity:
- 60 m for the 24,000 BTU/h model;
- 80 m for the 28,400 and 36,000 BTU/h models;
- 100 m for the 42,000 BTU/h model.
The maximum height difference can reach 15 or 25 m, depending on the model.
These options provide considerable design flexibility when the three indoor units are far apart.
However, we never seek to use the entire available length without reason. A more direct route generally makes the following easier:
- installation;
- line insulation;
- finishing;
- charge calculation;
- future service work.
R32 refrigerant charging cannot be improvised
The documentation also provides a line length covered by the factory charge and an amount of additional refrigerant required when that length is exceeded.
During commissioning, we therefore need to know the actual length of the network.
An incorrect refrigerant charge can affect performance, particularly when the system must operate under demanding conditions.
The R32 is an A2L-category refrigerant. The FREEMATCH R32 documentation indicates that an A2L leak detection sensor is included.
This does not replace rigorous refrigeration installation practices.
We must always:
- keep the lines clean;
- make the connections correctly;
- check for leaks;
- perform an appropriate vacuum;
- confirm the circuit lengths;
- adjust the charge when required;
- check the operation of all three zones.
The drain above the door requires particular attention
The visible head is installed directly above an opening used daily.
A condensate leak at this location would be particularly troublesome.
In cooling mode, moisture in the air condenses on the evaporator. The water is collected in a pan and then discharged through the drain.
Therefore, we must ensure:
- an appropriate slope when drainage is by gravity;
- no crushing of the pipe;
- no point where water can become trapped;
- a watertight connection;
- a properly positioned outlet.
We perform a flow test before fully closing up the job site.
This is one of the differences between a head that “works” when it starts up and one heat pump installation designed to remain reliable during humid summers.
Electrical requirements can vary significantly depending on the outdoor unit
Page 2 of the technical data sheet indicates different electrical requirements for each capacity compatible with three heads:
- 24,000 BTU/h: MCA 19.5 A, MOCP 25 A;
- 28,400 BTU/h: MCA 23 A, MOCP 35 A;
- 36,000 BTU/h: MCA 30 A, MOCP 45 A;
- 42,000 BTU/h: MCA 30 A, MOCP 45 A.
This difference explains why an old electrical circuit can never be declared compatible simply because it previously powered an air conditioner.
The selected model must be known before sizing the circuit and its protection.
Commissioning a three-head system must go further than a simple startup
Once all connections are complete, we test the zones individually and then together.
Our inspection includes, in particular:
- the first head;
- the second head;
- the third head;
- simultaneous operation;
- motorized louvers;
- fans;
- response to commands;
- supply-air temperatures;
- drainage;
- vibrations;
- communications with the outdoor unit.
The head photographed in Saint-Louis, with its display showing 21 and its louver open, illustrates precisely the visible phase of the system once it has been powered.
Behind this simple display, however, are three circuits that must operate coherently.
Operation down to -30 °C should not be confused with constant capacity
The heating range indicated in the specification sheet extends down to -30 °C.
This information means that the range is designed to operate within this range. It does not mean that the outdoor unit necessarily delivers its full rated capacity at -30 °C.
This distinction is especially important with three heads.
When the outdoor temperature drops sharply and all zones call for heat simultaneously, the available capacity must be distributed among the indoor units.
When choosing a heat pump for the Quebec climate, so we must analyze the low-temperature capacity and the building’s heat losses, not just the number of BTUs listed in the system name.
Mistakes to avoid when the head is installed above a door
Installing the unit too close to the ceiling
The head must maintain its airflow and access for servicing.
Drilling without considering the door structure
The space above an opening may contain structural and electrical elements that must be identified before routing the lines.
Directing the airflow straight at an occupied area
The location must be chosen according to the airflow path, not solely according to the available space.
Leaving the drain without a proper test
A seemingly well-installed drain may contain an invisible reverse slope.
Simply adding up the BTUs of the three heads
The outdoor unit has its own capacity, which is shared among the zones.
Using an AHRI reference that does not correspond to the combination
The documentation provides separate AHRI numbers for the non-ducted, ducted, and mixed configurations, and for the different outdoor units.
Warranty and discount availability
The provided sheet indicates a 10-year standard warranty and mentions an additional two-year extension with Wolseley when the registration and/or proof-of-installation requirements are met. It also states that the product line is eligible for local rebates.
Actual eligibility for a program must be confirmed based on:
- the outdoor model;
- the three indoor units;
- the AHRI number;
- the building;
- the purchase and installation date;
- the requirements of the applicable program.
We recommend keeping the models, serial numbers, certificates, detailed invoices, and registration records as soon as the work is completed.
Servicing the visible head in Saint-Louis
Since the unit is installed above the door, the filters are not immediately within reach. This is not a problem if safe access is provided for periodic cleaning.
The filters should be checked regularly, particularly if the room is used frequently.
A HVAC maintenance a more thorough inspection may also include:
- inspection of the evaporator;
- cleaning the blower wheel;
- checking the condensate pan;
- checking the drain;
- checking the cleanliness of the outdoor unit;
- inspection of accessible connections.
A reduction in airflow can be caused by a clogged filter long before a breakdown occurs.
A discreet integration that frees up the entire room
This 3-head GREE FREEMATCH R32 heat pump in Saint-Louis shows how an architectural constraint can be used intelligently.
The wall already had a door, a window, blinds, shelves, and furniture. Rather than adding the heat pump to the usable part of the room, we used the available space above the door.
The result preserves:
- the fully functional window;
- the unobstructed door;
- the existing shelves;
- the space intended for furniture;
- an unobstructed airflow path;
- reasonable access to the head for servicing.
However, this indoor unit is only one-third of the project. The true quality of the installation also depends on selecting the outdoor unit, sizing the three zones, the refrigerant piping, drainage, evacuation, R32 charge, and verification of each circuit.
At AirGreen, we apply this same logic when carrying out our heat pump installations in Montreal, Laval, Longueuil, on the North Shore, and on the South Shore : we are not simply looking for a space where the unit can fit. We are looking for the location where it can heat, cool, be serviced, and integrate into the building over the long term.
In Saint-Louis, this head mounted above the door precisely illustrates this approach: intelligently using the existing geometry to achieve a clean, functional, and truly suitable multi-zone HVAC installation.