Installing a high-performance heat pump in a very tight outdoor space: a typically Montreal project where every clearance mattered
At Ahuntsic-Cartierville, Montreal, we installed a MIDEA MIDEA28 wall-mounted heat pump in an outdoor configuration that required particularly precise planning. The site photograph immediately shows the main constraint: the outdoor unit had to fit into a narrow space, directly against the building, in close proximity to an exterior metal staircase and other architectural elements.
This type of situation is common in established neighborhoods of Montréal, where buildings were not always originally designed to accommodate modern HVAC equipment. Unlike a home with a large, completely unobstructed side yard, we sometimes have to work within just a few feet of space, between a foundation, a metal structure, a window, a passageway, or other existing installations.
For this project, our objective was therefore twofold: to properly install the MIDEA28 while making intelligent use of the available space.
The outdoor unit was installed on metal wall brackets, above ground level. This arrangement maintains clearance beneath the heat pump, prevents it from resting directly on the exterior surface, and better adapts it to the realities of Montreal winters.
The Midea brochure also presents its side-discharge outdoor units as compact appliances that can be installed on a base or bracket depending on the site configuration.
The proximity of the metal staircase completely changes how the installation must be planned
To the left of the heat pump, the photograph shows a metal staircase structure very close to the unit.
For an installer, this detail is far more important than it may seem.
An outdoor unit must be able to draw in and discharge air without excessive obstruction. The large front fan of the MIDEA28 must have enough open space to discharge the airflow produced by the unit. We must therefore avoid positioning the heat pump so that a wall, staircase, fence, or other obstacle compromises its operation.
For an installation of this type, we assess, among other things:
- the clearance in front of the fan;
- the distance between the unit and the staircase;
- access to the sides of the heat pump;
- the possibility of carrying out a future HVAC maintenance;
- the routing of the refrigerant lines;
- the positioning of the electrical connection;
- the height of the unit above the ground;
- drainage conditions during defrost cycles.
The challenge, therefore, is not simply determining whether the heat pump physically “fits” in the space. We must also ensure that it can operate and be properly serviced once installed.
A raised unit to better cope with snow and defrosting
The MIDEA28 shown in the photograph does not rest directly on the ground. We installed it on metal brackets firmly secured to the structure.
This height is particularly relevant to Montréal.
During winter, an outdoor unit may be exposed to snow, ice, and water resulting from its defrost cycles. A heat pump installed too low is more likely to become surrounded by accumulated snow or ice.
In heating mode, the outdoor coil extracts energy from the air. When conditions become cold and humid, frost can form on the coil. The unit then automatically performs a defrost cycle.
This defrosting generates water.
When the outdoor temperature remains below zero, this water can then freeze beneath the equipment. Providing adequate space beneath the heat pump therefore helps create an installation better suited to actual winter conditions.
A compact installation must never become an inaccessible installation
Another essential aspect of the project concerns future access to the equipment.
In the photo, the Midea is installed between the metal staircase and the wall, but the unit’s main sides remain accessible.
This is important because a heat pump will eventually need to be inspected or serviced. A technician may need access to the refrigerant connections, electrical components, fan, coil, or other internal parts.
We therefore avoid creating installations where the equipment is so tightly confined that even a simple service call requires dismantling a nearby structure.
An HVAC installation a well-planned installation considers the day it is commissioned, but also the next ten years of use.
MIDEA28: a heat pump designed for Quebec temperatures
The series MIDEA28 is presented in the manufacturer’s documentation as an extreme-climate heat pump, operating with R-454B refrigerant and identified Cold Climate V6.1.
For all the capacities listed in the brochure, Midea publishes a heating operating range down to -30 °C. The air conditioner can also operate within a published range from -30 °C to 50 °C.
For an installation at Ahuntsic-Cartierville, this ability to operate at very low temperatures is particularly relevant.
We nevertheless always emphasize one important distinction: a minimum operating temperature is not the same as a constant capacity at all temperatures.
To choose a heat pump correctly, you need to look at its actual low-temperature performance and compare it with the building’s heating requirements.
A range from 9,000 to 33,000 BTU/h
The MIDEA28 offers five nominal air-conditioning capacities:
- 9 000 BTU/h;
- 12 000 BTU/h;
- 18,000 BTU/h;
- 24 000 BTU/h;
- 33 000 BTU/h.
The corresponding indoor units are MSEHU-H09B-2A, MSEHU-H12B-2A, MSEHU-H18B-2A, MSEHU-H24B-2A, and MSEHU-H33B-2A.
The associated outdoor units bear the following model numbers: MO1HS-H09B-2A, MO1HS-H12B-2A, MO1HS-H18B-2A, MO1HS-H24B-2A, and MO1HS-H33B-2A.
The published AHRI numbers are, respectively, 215471380, 215471381, 215471382, 215471383, and 215471384.
The data plate of the photographed unit is not visible clearly enough for us to state its exact capacity. We therefore prefer not to arbitrarily assign a BTU rating to this unit.
This detail is important when comparing quotes: MIDEA28 refers to a series, not a single capacity.
Up to 27.4 SEER2: performance varies according to the selected capacity
The range’s advertised maximum efficiency reaches 27.4 SEER2, but it corresponds to the 9,000 BTU/h combination.
The published SEER2 values are:
- 9,000 BTU/h: 27.4 SEER2;
- 12,000 BTU/h: 25.4 SEER2;
- 18,000 BTU/h: 21.4 SEER2;
- 24,000 BTU/h: 21.0 SEER2;
- 33,000 BTU/h: 19.5 SEER2.
HSPF2 Region IV values range from 10.5 to 13,5 depending on capacity.
This variation explains why we avoid presenting a series solely with its best figure.
A serious proposal must identify the exact combination installed.
In Ahuntsic-Cartierville, the project’s success depended as much on the outdoor space as on the MIDEA28’s performance
Performance at -15°C is particularly worth examining
For Montreal’s climate, low-temperature heating data is essential.
At -15°C, Midea indicates a nominal heating capacity for the MIDEA28 of:
- 11,500 BTU/h for the 9,000 model;
- 11,500 BTU/h for the 12,000;
- 18,000 BTU/h for the 18,000;
- 24,200 BTU/h for the 24,000;
- 35,000 BTU/h for the 33,000.
The COPs published at this temperature are, respectively, 1.80, 1.80, 1.92, 2.34, and 1.98.
This data provides a better assessment of what the equipment can actually deliver when a Quebec winter is in full swing.
Why we never choose a heat pump solely based on square footage
Sizing a wall-mounted heat pump in Montreal should not be reduced to an automatic formula based solely on floor area.
We also consider:
- the building’s heat loss;
- insulation;
- windows;
- ceiling height;
- the number of floors;
- sun exposure;
- the layout of the rooms;
- natural air circulation;
- the existing heating system;
- the desired comfort level;
- the equipment’s performance as the outdoor temperature drops.
A larger unit is not automatically better.
A properly sized heat pump can modulate more extensively and maintain a more stable comfort level.
Variable speed helps the heat pump adapt to actual needs
Midea explains that its variable-speed technology allows the compressor to adjust its operation as heating or cooling demand changes.
Instead of operating only at full capacity and then shutting off, the system can modulate its output, helping limit indoor temperature fluctuations.
This feature is particularly beneficial when the heat pump has been properly sized.
The large outdoor fan visible in the photo explains why clearances are essential
In this Ahuntsic-Cartierville installation, the front fan occupies a large part of the outdoor unit's front panel.
This helps explain visually why we placed so much importance on the clearance in front of the unit despite the nearby staircase.
Midea's published outdoor airflow rates vary considerably depending on capacity. The MIDEA28 range goes from approximately 1,235 CFM to 2,235 CFM.
The 33,000 BTU/h model, for example, moves much more air than the smaller capacities.
Placing a unit directly in front of an obstruction that is too close can therefore have a direct impact on operating conditions.
Outdoor noise also matters in an urban neighborhood
In a dense area like Ahuntsic-Cartierville, proximity to neighbors can be an important factor in choosing the outdoor placement.
Depending on the capacity, Midea publishes outdoor sound levels ranging from approximately 56 dB(A) to 63.5 dB(A) for this series.
This does not mean that the heat pump will operate constantly at its maximum level. Variable-speed technology allows the system to adjust its operation to demand.
Nevertheless, we consider the unit's location in relation to windows, resting areas, neighboring properties, and regularly used outdoor spaces.
Mounting the unit: several dozen kilograms on two brackets
The photograph clearly shows the two metal arms supporting the Midea unit.
The outdoor unit's weight varies considerably depending on capacity:
- approximately 72.75 lb for the 9,000 and 12,000 BTU/h versions;
- 99.87 lb for the 18,000;
- 130.29 lb for the 24,000;
- 156.97 lb for the 33,000.
A wall bracket must therefore be selected and installed with the actual load in mind.
We also use suitable contact points and components to limit unnecessary vibration transmission to the building.
Refrigerant lines vary according to BTU capacity
The MIDEA28 uses several pipe diameters depending on capacity:
- 9,000 and 12,000 BTU/h: 1/4 in. and 3/8 in.;
- 18,000 BTU/h: 1/4 in. and 1/2 in.;
- 24,000 BTU/h: 3/8 in. and 5/8 in.;
- 33,000 BTU/h: 3/8 in. and 3/4 in..
This difference becomes very important in a replacement project.
An old pair of lines should not automatically be reused simply because it already reaches the chosen location.
We must confirm the diameter, condition, length, and installation compatibility with the new heat pump.
Up to 164 ft of piping depending on capacity
The published maximum length also differs from one model to another.
Midea indicates:
- 82 ft for the 9,000 and 12,000 BTU/h units;
- 98.4 ft for the 18,000;
- 164 ft for the 24,000 and 33,000 BTU/h units.
This flexibility can be particularly useful in Montreal buildings, where the ideal indoor location does not always correspond to the best outdoor location.
R-454B and A2L leak detection
The MIDEA28 uses R-454B, an A2L-classified refrigerant.
Midea's documentation also mentions an A2L refrigerant leak detection sensor, as well as dual temperature and humidity monitoring for the applicable series.
For us, this means that the equipment must be installed according to the practices and requirements corresponding to this new generation of systems.
The electrical requirements must be verified for each model
All the MIDEA28 capacities presented are powered by 208/230 V, single-phase, 60 Hz.
However, the outdoor unit's minimum allowable amperage is different:
- 15 A for the 9,000;
- 15 A for the 12,000;
- 19 A for the 18,000;
- 24.9 A for the 24,000;
- 34 A for the 33,000.
The maximum listed protections are respectively 15, 15, 20, 25, and 35 A.
That is why the model number must be known before confirming an installation's electrical requirements.
The MIDEA28's indoor functions
Although our photograph mainly highlights the outdoor unit, the owner's daily experience takes place primarily on the wall-mounted head side.
The MIDEA28 notably offers:
- mode ECO;
- Turbo;
- night mode;
- timer;
- child lock;
- function Follow Me;
- automatic cleaning;
- quiet mode;
- maintaining heating at 8 °C;
- horizontal and vertical swing;
- Wi-Fi control;
- smart sensor;
- humidity control.
Midea also indicates up to 100 airflow adjustment levels, allowing the indoor airflow to be adjusted more precisely.
Equipment also designed to facilitate maintenance
The brochure indicates that the MIDEA35, MIDEA28, and MIDEA25 series feature a removable blower wheel, making it easier to access the indoor unit during a deep cleaning.
This feature is of particular interest to us from the standpoint of theHVAC maintenance.
Washable filters can be cleaned regularly, but equipment used over several seasons also accumulates contaminants on the heat exchanger and blower wheel.
Equipment that is easily accessible is generally easier to keep in good condition.
The main mistakes to avoid in a tight outdoor installation
This Ahuntsic-Cartierville project illustrates several common mistakes.
Installing the unit only where there is room left
An open space is not necessarily an acceptable HVAC location. Airflow and service access must be verified.
Positioning the fan too close to a staircase or wall
The heat pump must be able to discharge its air properly.
Installing the unit directly on the ground without considering winter
Snow and defrost water must be considered from the planning stage.
Choosing a support that is too light
The largest MIDEA28 weighs approximately 157 lb according to the manufacturer’s documentation.
Automatically reusing the existing lines
Diameters vary by capacity and must match the model’s requirements.
Choosing the largest available unit
Proper sizing remains preferable to excessive capacity.
Financial assistance: verify the exact AHRI number
Midea documentation identifies the various MIDEA28 combinations by their AHRI references and presents them as Cold Climate V6.1.
However, the brochure provided does not confirm any subsidy amount for this particular installation in Ahuntsic-Cartierville.
For a program such as LogisVert, so we must verify the exact combination and the criteria in effect when the application is submitted.
The model number and AHRI reference are what allow for serious verification, not just the MIDEA28 designation.
Midea Residential Warranty
For residential applications, the brochure lists a limited warranty of 12 years on the compressor, 12 years on parts, and 10 years on labor, subject to the applicable terms.
The registration and coverage conditions must of course be met.
An AirGreen installation adapted to Ahuntsic-Cartierville’s real-world constraints
This installation aptly reflects the reality of many projects we carry out in Montréal.
We did not have a large, open area where the outdoor unit could be placed freely. We had to integrate a modern heat pump into an already built environment, with a metal staircase nearby, a foundation, limited circulation space, and service constraints to consider.
The visible result in the photo is a MIDEA28 installed on wall brackets, raised off the ground, with its front fan directed toward an area that is as open as possible given the configuration.
This is the type of consideration we bring to every HVAC installation in Ahuntsic-Cartierville, Montréal, Laval, Longueuil, the North Shore, and the South Shore.
The MIDEA28 has interesting specifications on paper: heating down to -30 °C, efficiency of up to 27.4 SEER2, several capacities up to 33,000 BTU/h, variable-speed operation, and R-454B refrigerant.
But a heat pump’s performance always starts with how it is installed.
For this project inAhuntsic-CartiervilleIn this case, the main challenge was precisely that: making the MIDEA28 work efficiently in a confined Montréal space without overlooking airflow, access, snow, defrosting, and support stability.
This is where installation quality becomes just as important as the equipment’s specifications.