Installation of a Hitachi airHome 800 wall-mounted heat pump in Duvernay, Laval

A high-mounted installation designed to protect the equipment and preserve outdoor space

This installation of a Hitachi airHome 800 wall-mounted heat pump in Duvernay, in the Laval area, perfectly illustrates the importance of adapting each HVAC project to the building’s actual architecture. Here, the outdoor unit could not simply be placed on the ground on a slab. The brick façade, the presence of windows, the available height, and circulation around the building required a more structured approach.

We therefore installed the outdoor unit on sturdy metal wall brackets, securely anchored in the masonry. This elevated positioning frees up the ground while keeping the unit away from accumulations of snow, ice, leaves, and debris that could interfere with its operation.

The photo also shows particularly important work for this type of project: coordinating the mechanical support, the refrigerant line routing, the electrical wiring, and future access for maintenance. A heat pump may perform very well on paper, but its durability largely depends on the quality of its HVAC installation.

Why install an outdoor unit so high on a brick wall?

In several neighborhoods of Duvernay, Montreal, and Laval, residential buildings have limited outdoor space. A narrow yard, a frequently used side passage, a terrace, a balcony, or an area used for storage can limit the available locations.

A high wall-mounted installation can then address several constraints:

• completely clear the ground;
• reduce the risk of burial by snow;
• keep the unit away from splashes, mud, and debris;
• preserve a passageway;
• maintain adequate clearance around the outdoor heat exchanger;
• limit the risk of accidental damage caused by a lawn mower, shovel, or outdoor furniture.

However, this method must never be improvised. An outdoor unit contains a compressor, a fan, a heat exchanger, and a refrigerant charge. Its weight and the vibrations produced during operation must be transferred safely to the building structure.

Anchoring into masonry: a detail that determines stability

On a brick facade, we assess the condition of the wall before securing the supports. Decorative brick, deteriorating mortar, and the load-bearing structure behind the cladding must not be considered interchangeable.

The supports must be:

• suitable for the unit's weight;
• precisely leveled;
• anchored in sufficiently strong material;
• positioned to comply with the manufacturer's clearances;
• equipped with components that help limit vibration transmission.

Improper mounting can cause noise in the building, gradual movement of the support, stress on the refrigerant connections, or deformation of the equipment base. At AirGreen, we therefore treat the wall support as an essential mechanical component, not merely an accessory.

Preventing vibrations in bedrooms and occupied rooms

When a heat pump is installed near a window or on a wall adjacent to a bedroom, vibration control becomes particularly important. Even a relatively quiet outdoor unit can transmit resonance through the masonry if the supports, anchors, or contact points have not been properly prepared.

We specifically check:

• the rigidity of the support;
• the distance between the unit and the wall;
• the presence of unwanted contact points;
• the positioning of the lines;
• the insulation of the refrigerant pipes;
• the securing of the wiring and drain.

A line that touches brick or exterior cladding can produce a vibration noise that is much more noticeable than the compressor itself.

A clean, accessible line route

For this installation in Duvernay, the lines are routed horizontally along the facade. This type of route requires careful planning to avoid windows, architectural elements, and other building services.

Refrigerant lines must be protected against:

• crushing;
• ultraviolet rays;
• water infiltration;
• friction against the masonry;
• stress caused by temperature changes;
• damage during future work on the facade.

We also pay particular attention to the slope and positioning of the condensate drain. In air conditioning, the indoor unit removes moisture from the air. This water must be drained properly, without flowing back toward the building, dripping onto a window, or creating a slippery area.

A Hitachi heat pump designed for Quebec’s climate

The Hitachi airHome 800 is an Inverter wall-mounted heat pump offered in several capacities, from 9,000 to 24,000 BTU/h. Depending on the indoor-outdoor combination selected, the series can operate in heating mode down to -30 °C and maintain its rated heating capacity at -20 °C. The models offer seasonal cooling efficiency of up to TRÉS2 of 26.5, as well as a CPSC2 for region 5 of up to 9.7. The series uses R32 refrigerant.

This data is particularly relevant for homeowners in Laval, where the heat pump must handle both the hot, humid periods of summer and episodes of intense cold in winter.

A capacity that must be selected, not guessed

The photo makes it possible to identify the Hitachi airHome 800 series, but it is not sufficient to confirm the exact capacity of the unit. We never determine the number of BTUs solely from the approximate area or the visual size of the outdoor unit.

The choice between 9,000, 12,000, 18,000, or 24,000 BTU/h depends, among other things, on:

• the area actually served;
• the number of floors;
• the layout of the rooms;
• insulation;
• solar orientation;
• the number of windows;
• ceiling height;
• air infiltration;
• the location of the indoor unit;
• of low-temperature heating needs.

An oversized heat pump can quickly reach the requested temperature and then run shorter cycles. This can reduce dehumidification and create comfort fluctuations. An undersized unit may run continuously without meeting demand on the coldest days.

Different connections depending on capacity

An aspect often overlooked when replacing an old heat pump is the diameter of the refrigerant lines. In the airHome 800 series, the connections are not identical for all capacities:

• the 9,000 and 12,000 BTU models use 1/4 in and 3/8 in fittings;
• the 18,000 BTU model uses 1/4 in and 1/2 in fittings;
• the 24,000 BTU model uses 3/8 in and 5/8 in fittings.

This difference is important when a homeowner wants to reuse existing piping. The diameter, length, condition of the insulation, interior cleanliness, and compatibility with the new refrigerant must be checked before keeping an old line.

Automatically reusing existing lines to reduce the installation cost may compromise system performance or make the installation non-compliant with the manufacturer's requirements.

Electrical requirements also vary

According to the product line's technical documentation, the 9,000 and 12,000 BTU models have a minimum circuit ampacity of 14 A and maximum overcurrent protection of 25 A. The 18,000 and 24,000 BTU versions require a minimum circuit ampacity of 20 A and maximum overcurrent protection of 35 A.

However, the electrician must always rely on the nameplate of the unit actually installed, the manufacturer's manual, and the requirements applicable in Quebec. The circuit breaker must not be selected solely based on the nominal capacity stated in a quote.

FrostWash 3.0, Mold Guard 2.0, and PM2.5 filtration

The Hitachi airHome 800 also stands out for several functions related to the cleanliness of the indoor unit.

The FrostWash 3.0 technology uses a heating, freezing, and thawing cycle to help loosen particles accumulated on the heat exchanger. The system first heats the coil, then cools it until frost forms. When the ice melts, some of the dust and contaminants are discharged with the water.

The Mold Guard 2.0 function monitors conditions inside the unit when it is turned off. When conditions favorable to mold growth are detected, the system can heat the indoor coil to dry it.

The unit also includes a PM2.5 activated carbon filter and a stainless steel prefilter. These devices help reduce certain particles and odors present in recirculated air.

These technologies help maintain cleanliness, but they do not replace professional HVAC maintenance. Filters must still be cleaned, the drain must be checked, and the heat exchanger must be inspected periodically.

Heating, cooling, and humidity control

In summer, the heat pump absorbs indoor heat and rejects it outdoors. The dehumidification mode can also help reduce humidity without causing excessive cooling.

Dehumidification capacity varies by model. In the series documentation, it ranges approximately from 2.1 to 4.5 liters per hour under the test conditions specified by the manufacturer. Actual results, however, depend on the indoor temperature, humidity level, and fan speed.

In winter, Inverter technology modulates the compressor’s operation rather than operating only at full power or being switched off. This modulation generally helps maintain a more stable temperature, with fewer abrupt fluctuations.

Connected control with airCloud Go

The airHome 800 range’s Wi-Fi interface allows you to use the airCloud Go app. The homeowner can adjust the temperature, schedule operating times, view certain consumption data, and receive information about the system’s operation.

Available features include:

• weekly scheduling;
• remote control;
• voice control compatible with certain assistants;
• Smart Eco mode;
• the SleepSense function;
• the display of error codes;
• the activation of certain cleaning functions.

For a homeowner who regularly leaves their home or has variable schedules, remote control makes it possible to lower the temperature without sacrificing comfort upon returning.

What this Duvernay installation demonstrates about sustainable HVAC installation

The best location is not always the easiest one

The outdoor unit’s location directly affects its accessibility, noise level, exposure to the elements, and ability to discharge air.

In this installation, the elevated positioning avoids occupying ground-level space. It also reduces exposure to snow accumulation. However, the heat pump remains accessible for servicing with the appropriate work equipment.

An installation too close to a soffit, balcony, side wall, or another obstacle can cause discharged air to recirculate. In heating mode, this recirculation can reduce performance and increase the frequency of defrost cycles.

Managing snow and defrost water

A heat pump produces water during its winter defrost cycles. When the unit is installed on the ground, this water can freeze beneath the unit and gradually form a mass of ice.

Elevated positioning helps keep the unit away from this accumulation, but you still need to plan where the water will fall. It must not create a hazard above a door, staircase, or frequently used passageway.

The Hitachi brochure also recommends snow protection for cold climates when the site’s exposure warrants it. The choice of such an accessory depends on the building’s orientation, prevailing winds, and the presence of significant accumulations.

Mistakes to avoid during a wall-mounted installation

For a heat pump installed on a brick façade, several mistakes can compromise the quality of the result:

1. Fastening the brackets only into weakened cladding.
2. Installing the unit without checking its level and alignment.
3. Allowing the pipes to vibrate against the brick.
4. Neglecting access to the service panels.
5. Directing the drain toward a window or a passageway.
6. Reducing clearances to conceal the unit more effectively.
7. Using a pipe diameter that is incompatible with the model.
8. Choosing the breaker without checking the nameplate.
9. Failing to provide for defrost water drainage.
10. Installing a capacity that is too high for the area being served.

Eligibility for subsidies must be verified based on the exact model

Hitachi airHome 800 documentation indicates that the range may qualify for several provincial heat pump incentives. Actual eligibility must nevertheless be confirmed based on the exact combination of indoor and outdoor models, the applicable certification and the program rules in effect when the application is submitted.

Before installation, we verify the necessary information, including:

• the complete model numbers;
• the recognized performance reference;
• low-temperature heating capacity;
• the type of building;
• the existing heating system;
• the documents required by the program.

The trade name “airHome 800” alone is not enough to guarantee financial assistance.

The AirGreen approach in Duvernay and Greater Montreal

This project demonstrates how we approach wall-mounted heat pump projects in Laval: we assess the building, masonry, available space, pipe routing, electrical requirements and future maintenance needs before choosing the fastening method.

We carry out HVAC installations in Montreal, Laval, Longueuil, the North Shore and the South Shore, with the same attention to details that are not always visible once the work is complete: vacuum quality, connection tightness, pipe insulation, drainage, fastening, vibration control and commissioning.

A properly sized and installed Hitachi airHome 800 heat pump can provide efficient heating during Quebec winters, stable cooling in summer, and more precise control of indoor comfort. In a brick building like the one in Duvernay, the project’s value depends as much on the unit’s technology as on the quality of the installation supporting it.