Installation of a Hitachi airHome 600 wall-mounted heat pump in Saint-Lambert on Montreal’s South Shore

A compact installation at the heart of a bright living area

For this wall-mounted Hitachi airHome 600 heat pump installation in Saint-Lambert, the main challenge was integrating the indoor unit into an open living area without encroaching on the glazed surfaces, curtains, switches, or traffic areas.

The project photograph shows a typical configuration found in several renovated Saint-Lambert residences: a large window lets in plenty of natural light, the ceiling features recessed lights, and an architectural drop separates certain areas of the room visually. The wall available for the heat pump was therefore relatively short and ended immediately near the window.

We placed the Hitachi airHome 600 in the upper part of this section of wall, near the corner, to keep the lower area completely clear. This positioning protects the interior layout while allowing the air outlet louvre to direct air toward the open part of the room.

Several factors were taken into consideration:

• the proximity of the large window;
• the clearance below the ceiling;
• the full opening of the sash;
• the routing of the connections on the right side;
• the presence of switches lower down on the wall;
• air circulation toward the adjacent room;
• future access to the filters and internal components;
• the overall appearance of the installation.

The result is a compact HVAC installation, adapted to the existing architecture and particularly suitable for a room where available wall space is limited.

Use a short section of wall without blocking the window

Installing a heat pump near a window requires greater precision than an installation carried out in the centre of a large, unobstructed wall. The unit must not interfere with the blind’s operation, encroach on the frame, or receive excessive direct sunlight that could affect the temperature reading.

In this Saint-Lambert project, the unit was positioned far enough to the left of the window to ensure that the blind and its housing could remain functional. The Hitachi’s front remains unobstructed, while the lower sash can open without touching the frame.

The window also represents a significant area of heat gain and loss. In summer, sunlight can quickly increase the temperature near the glazing. In winter, a window can create a cold-wall sensation, even when it is recent and properly installed.

The choice of location allows the heat pump to efficiently treat the air in the area near the glazing while directing its airflow toward the center of the living area.

Why we avoid placing the unit directly above a blind

An indoor unit installed too close to a blind casing can cause several problems:

• difficulty removing the blind for repairs;
• limited access to the heat pump connections;
• partial obstruction of the blind;
• vibration of the blind casing when the fan is running;
• a cluttered appearance around the window;
• irregular airflow.

We therefore aim to maintain visual and functional separation between the two pieces of equipment. This attention to detail is particularly important in homes in Saint-Lambert, where interior renovations often combine older structures with contemporary finishes.

A side exit protected by a finishing cover

The photograph shows a white cover installed immediately to the right of the indoor unit. This piece protects the transition between the heat pump and the passage for the lines.

Several essential components may be located inside this area:

• the copper refrigerant lines;
• the line insulation;
• the communication cable;
• the electrical connection, depending on the configuration;
• the condensate drainpipe.

A side exit is often used when the opening cannot be positioned directly behind the unit. The wall structure, the desired exterior location, or the interior layout may require an offset.

The finishing cover provides a cleaner transition than a set of exposed lines. It also protects the insulation from impacts and reduces the risk of a component being moved while the room is being serviced.

Controlled bending of the lines

The copper lines must not be forced into an overly tight angle. Excessive bending can reduce refrigerant flow, damage the insulation, or place stress on the connections.

During installation, we allow enough space to gradually shape the lines before connecting them to the indoor unit. We also check that the drainpipe maintains the necessary slope.

This part of the work becomes invisible once the casing is closed, but it directly affects the system’s reliability.

Drainage: an invisible detail that protects the wall

In cooling and dehumidification modes, the indoor unit removes moisture from the air. This water collects in a pan and then drains away through a drainpipe.

Drainage must be planned even before permanently securing the mounting plate. An insufficient slope can lead to:

• water accumulation;
• draining noises;
• odors;
• an overflow beneath the unit;
• marks on the wall;
• a more rapid obstruction of the line.

In an installation located near a window, water damage could also reach the frame or adjacent finishes. We therefore pay particular attention to the unit’s level, the drain pan’s position and the drain route.

When gravity drainage is possible, it generally remains the simplest and quietest solution. If the configuration requires a condensate pump, it must be selected, positioned and maintained correctly.

Air distribution directed toward the open space

The Hitachi airHome 600 was installed to blow toward the unobstructed part of the room. This orientation is essential in an open-plan area.

In cooling mode, cool air can be directed forward so that it mixes with the ambient air before descending. In heating mode, the louver can be angled further downward to bring the heat into the occupied zone.

The unit must not blow directly against:

• a partition located nearby;
• a tall piece of furniture;
• a curtain;
• a door that remains closed;
• a television or sensitive equipment;
• an armchair used for several hours.

In this installation, the lower part of the unit remains completely unobstructed. The wall switches are low enough not to interfere with airflow or technical access.

An installation close to the ceiling, yet accessible

The top of the wall offered limited space because of the dropped ceiling. We therefore had to use the available height precisely without placing the heat pump flush against the ceiling.

The indoor unit’s air intake is located primarily in its upper section. A unit installed too close to the ceiling may draw in less air, become noisier and be more difficult to clean.

We make sure that the front panel can be opened and the filters can be removed. This check is important because the owner will need regular access to the filters to maintain airflow.

The airHome 600 series was designed with several features that simplify installation and maintenance, including an optimized mounting plate, easier access to several components, a drainage connection that can be oriented to the left or right and, depending on the capacity, a removable drain pan.

The technical reasons behind choosing the Hitachi airHome 600

The Hitachi airHome 600 is a range of wall-mounted heat pumps with Inverter technology, available in several capacities. The technical table lists models with nominal cooling capacities ranging from 9,000 to 22,000 BTU/h, with nominal heating capacities ranging from 11,000 to 25,200 BTU/h.

The exact capacity of the unit installed in Saint-Lambert cannot be confirmed from the photograph alone. Several units in the range share very similar dimensions.

The 9,000, 12,000, and 15,000 BTU/h models notably have an indoor width of approximately 37.4 inches. We must therefore always check the nameplates and the complete combination of indoor and outdoor units.

Sizing appropriate for the living area

The choice of BTU capacity should not depend solely on floor area. In this room, the large window, ceiling height, and opening to the adjacent area affect the heat load.

Our analysis takes several factors into account:

1. the area actually served;
2. the room’s air volume;
3. the amount of glazing;
4. solar orientation;
5. the insulation in the walls and ceiling;
6. the airtightness of doors and windows;
7. the layout of open spaces;
8. the number of occupants;
9. the presence of heat-producing appliances;
10. the expected contribution to winter heating.

A heat pump that is too small could run continuously on extreme days without maintaining the desired temperature. A model that is too large could reach the setpoint too quickly, reduce dehumidification, and create less comfortable cycles.

Inverter technology enables significant modulation, but initial sizing remains essential.

A heat pump designed to heat down to -25 °C

Saint-Lambert’s climate requires a unit capable of operating during genuinely cold periods. The Hitachi airHome 600 has a heating operating range extending down to -25 °C.

However, available capacity varies with the outdoor temperature. At -25 °C, the manufacturer’s table indicates a maximum capacity of approximately:

• 7,200 BTU/h for the 9,000 BTU/h model;
• 8,800 BTU/h for the 12,000 BTU/h model;
• 10,500 BTU/h for the 15,000 BTU/h model;
• 12,900 BTU/h for the 18,000 BTU/h model;
• 15,000 BTU/h for the largest model.

These values make it possible to assess the heat pump’s actual contribution more accurately during a cold snap. The nominal capacity indicated in a model name does not automatically represent its output at -20 °C or -25 °C.

We therefore compare low-temperature performance with the building's heat losses and the existing backup heating system.

Seasonal efficiency ratings suited to regular use

Depending on the selected capacity, the range can achieve efficiency ratings of up to 23.0 SEER2 and 9.2 HSPF2 for climate region 5. All combinations shown in the table are ENERGY STAR certified.

These ratings differ from one model to another. For example, the highest capacity does not necessarily have the best seasonal efficiency.

A thorough comparison should include:

• the SEER2;
• the HSPF2 for the appropriate region;
• capacity at -8 °C;
• capacity at -15 °C;
• capacity at -20 °C;
• sound level;
• airflow;
• electrical requirements.

The series uses R32 refrigerant. Pipe diameters vary according to capacity: smaller models generally use 1/4 in and 3/8 in connections, while larger models may require a 1/2 in or 5/8 in gas pipe.

This difference must be verified during a replacement. Existing lines cannot be reused without confirming their diameter, condition, and compatibility.

Inverter technology and comfort in a room with extensive glazing

Inverter technology adjusts the compressor speed according to the room's needs. Near a large window, the load can change quickly when the sun appears or disappears.

The heat pump can then increase its capacity when the solar gain becomes significant, then gradually reduce its operation when the temperature stabilizes.

This modulation promotes:

• more consistent temperature;
• energy consumption better matched to demand;
• fewer abrupt starts;
• better humidity management;
• more consistent sound levels;
• a gradual response to changes in solar radiation.

In an open-plan area, it is often preferable to maintain moderate ventilation for an extended period rather than alternate between very strong airflow and a complete shutdown.

FrostWash 3.0 for the indoor coil

The Hitachi airHome 600 features FrostWash 3.0 technology. The process acts in three phases on the indoor heat exchanger.

The coil is first heated to help loosen certain deposits. It is then cooled until ice forms, trapping some of the dust and contaminants. The ice eventually melts and carries the particles toward the drain.

The function can be activated manually or automatically according to the settings.

FrostWash helps keep the coil cleaner, but it does not replace complete HVAC maintenance. The filters must still be cleaned periodically, and the blower wheel may accumulate deposits despite the self-cleaning cycle.

Mold protection

The mold-protection function circulates air through the internal components and heats the coil under certain conditions to reduce residual moisture.

This function can limit conditions that promote odors, but it does not eliminate existing contamination. A persistent odor requires an inspection of the unit, pan, and drainage.

PM2.5 and activated-carbon filter

The series includes a stainless-steel prefilter and a PM2.5 activated-carbon purification filter. These components help capture certain small particles and reduce odors in the air passing through the unit.

The heat pump is nevertheless a local recirculation system. It does not replace an air exchanger or bring fresh air into the building.

In a Saint-Lambert home where air quality is a concern, we can assess separately:

• air renewal;
• bathroom ventilation;
• kitchen exhaust;
• indoor humidity;
• the presence of an air exchanger;
• additional filtration needs.

Quiet operation for a living area

The sound level varies according to the capacity and fan speed. The manufacturer indicates operation as low as approximately 27 dB(A) for a specific combination in quiet mode.

Installation nevertheless affects the noise that is actually perceived. We therefore check:

• the wall plate’s attachment;
• the unit’s engagement with its support;
• the absence of direct contact between the copper and the structure;
• the drain’s stability;
• the proper closure of the side panel;
• vibrations from the outdoor unit.

In a living area, mechanical noise or a repetitive vibration can become more bothersome than the normal sound of the fan. Commissioning tests make it possible to correct these details before the work is completed.

Wi-Fi control with airCloud Go

The Wi-Fi adapter is included in the airHome 600 combinations presented by Hitachi. The airCloud Go app allows you to schedule the heat pump, adjust the temperature remotely, and access certain energy-monitoring features.

The series also offers features such as Smart Eco, which uses a presence sensor to adjust operation when the room remains unoccupied.

In a living area used according to variable schedules, programming can avoid unnecessarily maintaining the same temperature throughout the day.

Financial assistance to be confirmed before installation

The documentation indicates that the range may qualify for several provincial heat pump incentives. However, eligibility and the amount should never be assumed based on the brand alone.

They depend in particular on:

• of the exact model combination;
• of the capacity recognized by the program;
• of the building type;
• of the applicable criteria;
• of the work date;
• of the heating source;
• of the documents provided;
• of the equipment registration.

We recommend keeping the detailed invoice, model numbers, serial numbers, and photographs of the rating plates.

The mistakes we avoid near a window

Installing the unit too close to the blind

The blind must remain accessible and must not vibrate due to the airflow.

Blocking the opening of the upper panel

The owner must be able to remove the filters without disassembling the window casing.

Directly exposing the sensor to sunlight

An inaccurate reading can lead to operation that does not correspond to the room's average temperature.

Neglecting drainage

A leak near a window can damage the wall, frame, or floor.

Installing a capacity that is too high to compensate for the glazing

The selection must be based on an overall calculation, not on a single characteristic of the room.

Overlooking the reach toward the open area

The louver must be able to direct air in the right direction without immediately encountering a partition.

The result of this AirGreen installation in Saint-Lambert

This project shows how a Hitachi airHome 600 wall-mounted heat pump can be integrated into a relatively narrow section of wall, near a large window and beneath a ceiling soffit.

We made use of the available height, kept the blind clear, and protected the side outlet with a finish enclosure matching the unit. The unit remains accessible, while the lower part of the wall stays clear for circulation and furnishing.

At AirGreen, we carry out this type of HVAC installation in Saint-Lambert, as well as in Montreal, Laval, Longueuil, the South Shore, and the North Shore. Each location is assessed based on the structure, windows, drainage, line routing, and expected air distribution.

A well-planned installation allows the heat pump to blend into the room without compromising comfort, maintenance, or existing architectural features.