A high installation designed to efficiently heat and cool an open interior volume
This installation of a Hitachi airHome 800 wall-mounted heat pump carried out in Laval-des-Rapides does not correspond to a conventional installation above a window or on the exterior wall of a rectangular living room. The indoor unit had to be positioned in the upper part of a stairwell, where a vertical wall, a sloped ceiling, and a second wall forming a narrow angle meet.
The job-site photograph immediately shows the main challenge: the unit is located at considerable height, in an area where access, leveling, and handling the unit require a rigorous work method. An extension ladder was used to reach the installation area, with protection at the contact points to limit marks on the painted surfaces.
This placement served a specific purpose: to use the building’s height to promote air distribution throughout an open volume while avoiding the use of a more functional wall in the living area. In a home with a sloped ceiling or an open stairwell, the positioning of the heat pump has a major impact on air circulation between levels.
A unit installed near a sloped ceiling without blocking its air intake
A wall-mounted heat pump primarily draws in ambient air through its upper section before circulating it through its heat exchanger. It is therefore not enough to find a surface large enough for the mounting plate. Sufficient space must also be maintained around the housing so that the unit can breathe properly.
In this installation in Laval-des-Rapides, we had to take all of the following into account simultaneously:
- the slope of the ceiling;
- the angle formed by the two walls;
- the actual width of the indoor unit;
- the space required to open the front panel;
- access to the filters;
- the direction of the airflow;
- the routing of the refrigerant lines and drain;
- the possibility of carrying out future HVAC maintenance.
A unit installed too close to the ceiling may experience restricted air intake. Conversely, a unit placed too low in a stairwell may send air directly against a wall or limit its reach toward open areas. We therefore sought a balance between the available height, technical clearances, and air distribution.
Why install a heat pump so high?
In an open-plan area with a staircase or a cathedral ceiling, a high installation can be advantageous, particularly in cooling mode. Cool air naturally descends and can be projected over a longer distance when the unit is correctly oriented.
In heating mode, the situation requires more attention because warm air tends to rise. Adjusting the louvers then becomes important. The air must be directed sufficiently downward to reach the occupied area before gradually rising.
The Hitachi airHome 800 features motorized louvers and multiple fan speeds to adapt air distribution. During commissioning, we therefore check not only the discharge temperature but also the actual behavior of the airflow in the room.
For a configuration like this, we explain to the owner in particular how to:
- direct the louvers downward in heating mode;
- use a sufficient fan speed to move air through the stairwell;
- avoid continually changing the set temperature;
- let the Inverter technology gradually modulate its output;
- adjust operation according to the temperature at different levels.
Working at height requires more than just a ladder
Mounting an indoor unit at this height requires more precise preparation than a standard-height installation. The unit must be lifted, aligned, and hooked onto its plate without damaging the connections behind the casing.
Before mounting the unit, we must confirm that the plate is perfectly stable and level. A slight incline can interfere with condensate drainage and cause water to accumulate in the indoor unit's drain pan.
We must also avoid applying excessive pressure to:
- the copper lines;
- the drain connection;
- the communication cable;
- the refrigerant insulation;
- the unit casing;
- the wall-plate fasteners.
The photograph shows a unit installed in a corner where lateral workspace is limited. For our technicians, this means that several operations must be prepared on the ground before final placement. The connection must never depend on a forced movement performed at the top of the ladder.
A discreet interior finish despite the complexity of the route
No long indoor raceway is visible in the photographed area. The unit therefore blends discreetly into the painted surface, despite its unusual position.
For this type of project, we aim to shorten the visible portion of the route as much as reasonably possible without creating excessively tight bends in the copper lines. A refrigerant line that is bent sharply can deform, restrict refrigerant flow, or weaken the copper.
The drain must maintain a continuous slope when operating by gravity. In a high installation, a hidden back pitch behind the unit may remain unnoticed until water begins running down the wall.
That is why we test the drainage before completing the work. We check that water poured into the pan drains properly to the outside or to the designated drainage point, without backflow or leaks.
Think about filter cleaning now
An indoor unit installed very high up offers certain air-distribution advantages, but it makes periodic filter cleaning less accessible. This aspect must be clearly explained to the owner.
The filters of a wall-mounted heat pump must be inspected regularly. A dust-covered filter reduces airflow, increases noise, and may impair the unit’s performance. In a location like this, stable access equipment is necessary; do not attempt to reach the unit by standing on a chair or stretching from the stairs.
During professional HVAC maintenance, access at height must also be planned. Our teams account for the space needed to open the panel, remove the filters, inspect the heat exchanger, clean the fan, and check the condensate drain pan.
What the Hitachi airHome 800 brings to this Laval-des-Rapides residence
A range from 9,000 to 24,000 BTU/h
The nameplate is not legible in the photograph, so we cannot arbitrarily assign a specific capacity to the installed unit. The Hitachi airHome 800 lineup includes four main combinations of 9,000, 12,000, 18,000, and 24,000 BTU/h.
Depending on the version, the nominal cooling capacities indicated by Hitachi are 9,500, 12,500, 18,000, and 22,000 BTU/h, respectively. The nominal heating capacities range from 12,000 to 25,400 BTU/h.
This distinction is important. The number of BTUs in the commercial name does not tell the whole story. We must also examine:
- heating capacity at subzero temperatures;
- the area actually open to the unit;
- the number of levels;
- the building’s heat loss;
- the quality of the insulation;
- the number of windows;
- solar orientation;
- the other heating appliances present.
In a stairwell, the calculation should not be based solely on the surface area of the wall where the unit is installed. The volume of air communicating with that area must be analyzed, along with how far the heat pump can reasonably distribute its heat.
HeatForce heating down to −30 °C
The HeatForce technology of the airHome 800 series is designed for heating in cold climates. Hitachi indicates a heating operating range down to −30 °C for all four capacities in the lineup.
The manufacturer also states a maximum capacity corresponding to 100% of the nominal heating capacity at −20 °C. At −30 °C, output remains available, but it decreases depending on the model: it is specified at 5,500 BTU/h for the 9,000 version, 6,000 BTU/h for the 12,000, 12,960 BTU/h for the 18,000, and 15,000 BTU/h for the 24,000.
These data allow us to explain an essential nuance to homeowners in Laval, Montréal, Longueuil, the North Shore, and the South Shore: a heat pump capable of operating at −30 °C does not necessarily produce its full maximum output at that temperature.
The existing supplemental heating must therefore remain available when the residence’s heat losses exceed the capacity produced by the heat pump during the coldest days.
Efficiency of up to 26.5 TRÉS2
Performance varies according to the selected capacity. The 9,000 BTU/h version reaches up to 26.5 TRÉS2, while the 12,000, 18,000, and 24,000 BTU/h versions show 25.0, 21.5, and 21.0 TRÉS2, respectively.
For heating, the region 5 CPSC2 can reach 9.7 on the smallest model. The other versions indicate values of 8.7 or 8.5 for this same climate region.
These ratings are used to compare system efficiency, but actual performance also depends on the installation. An excellent rating does not compensate for:
- an improperly sized system;
- inadequate airflow;
- a clogged heat exchanger;
- an improperly prepared refrigerant line;
- an incorrect refrigerant charge;
- an outdoor unit buried in snow;
- a continuously changing setpoint temperature.
An Inverter compressor better suited to long operating periods
Inverter technology allows the heat pump to modulate its output rather than operating exclusively at full capacity.
In this Laval-des-Rapides residence, this modulation is particularly relevant. The open volume of the stairwell may require prolonged operation at low or medium output to stabilize the temperature between the connected areas.
A properly selected system can thus maintain more consistent comfort, with fewer abrupt fluctuations than a system that starts and stops frequently.
We generally recommend choosing a reasonable temperature and letting the system maintain it. A significant setback followed by a rapid increase can force the heat pump to operate at high output, whereas stable maintenance would have been more efficient.
Quiet operation for a central space
A unit installed in a stairwell is often located near several rooms. Noise level therefore becomes an important consideration.
The 9,000 and 12,000 BTU/h indoor units can go as low as 30 dB(A) in quiet mode. The 18,000 and 24,000 BTU/h versions provide higher airflow rates and have a stated minimum level of 36 dB(A).
However, continuously using the quietest mode is not always ideal in a large space. A speed that is too low can limit the air reach. We therefore look for the setting that offers the best balance between acoustic comfort and heat distribution.
FrostWash 3.0 and Mold Guard 2.0
The airHome 800 includes several features focused on keeping the indoor heat exchanger clean.
FrostWash 3.0 first heats the coil, then cools it until frost forms, trapping some of the dust and contaminants. The melting frost then carries the particles into the drain.
Mold Guard 2.0 monitors internal conditions when the unit is turned off. When conditions favorable to mold growth are detected, the system can heat and dry the indoor coil.
The documentation also mentions a PM2.5 activated carbon filter and a stainless steel pre-filter. These features help manage cleanliness, but do not replace filter cleaning or periodic inspection of the unit.
Wi-Fi control with airCloud Go
The Wi-Fi interface for the airCloud Go app is included with the airHome 800 series. It is discreetly installed inside the unit.
The owner can use the app to:
- adjust the temperature remotely;
- create a weekly schedule;
- activate certain functions;
- view an estimated energy consumption;
- receive certain operating information;
- display error codes;
- use the Smart-Fence function;
- integrate the unit with Amazon Alexa or Google Home.
In an installation that is difficult to access, connected control is particularly convenient. Most everyday adjustments can be made without directly touching the unit.
Smart Eco and SleepSense for better setpoint management
The integrated motion sensor can detect when the room is unoccupied. With Smart Eco, the unit switches to energy-saving mode after a period of inactivity, then returns to its initial setting when occupants return.
The SleepSense feature adjusts the temperature according to configured sleep preferences. In a home where the stairwell connects to the bedrooms, this gradual management can help limit nighttime temperature fluctuations.
Eligibility for the LogisVert program
At the time of writing this article, Hydro-Québec provides assistance of $50 per 1,000 BTU/h of heating capacity at −8 °C for an ENERGY STAR-certified heat pump, or $120 per 1,000 BTU/h at −8 °C when it meets the “cold climate” criteria. The assistance available for a residential heat pump can reach $6,700, subject to the program requirements.
The amount must not be calculated based on the nominal capacity indicated in the commercial name. It depends on the exact combination of the indoor and outdoor model numbers, its recognized capacity at −8 °C, and the list in effect on the installation date.
Hydro-Québec specifies that eligible models and amounts may change. Verification must therefore be carried out using its search tool, based on the complete model number or AHRI number. The application must normally be submitted within nine months of installation.
Since the exact capacity of the photographed unit is not visible, it would be incorrect to announce a specific subsidy here. At AirGreen, we verify the actual combination being proposed before presenting the client with an estimate of the financial assistance available.
The details that determine the final quality
This HVAC installation in Laval-des-Rapides shows that a successful project depends on more than just the brand selected. The indoor location required particular attention to the height, sloped ceiling, wall angles, air distribution, and future access.
Before handing the system over to the owner, our commissioning process includes, among other things:
- checking the stability of the wall plate;
- checking the unit's level;
- testing the condensate drain;
- checking the refrigerant connections;
- evacuating the circuit;
- checking for leaks;
- testing in cooling and heating modes;
- the observation of vibrations and noises;
- the initial adjustment of the louvers;
- the explanation of the main controls.
This method is the same one we use for our wall-mounted heat pump installations in Montreal, Laval, Longueuil, on the North Shore and the South Shore: adapting the system to the building rather than forcing the building to adapt to a standardized installation.