An indoor installation that had to work with the existing architecture without sacrificing comfort
This installation carried out in Hemmingford, choosing the heat pump was only part of the work. The job-site photograph shows a particularly interesting detail: the indoor unit of the MIDEA MIDEA35 wall-mounted heat pump was installed very high on the wall, above a fixed architectural element made up of multiple openings. In this type of configuration, a few centimeters can completely change the quality of the installation.
We needed to achieve a result that remained visually clean, allowed the conditioned air to spread properly throughout the room, and maintained the accessibility needed for future servicing of the unit. This is exactly the kind of situation in which field experience in HVAC installation becomes just as important as the specifications listed on a data sheet.
The MIDEA35 is part of Midea’s ductless wall-mounted systems and is intended for applications where heating and cooling a zone is desired without adding a duct network. The Midea lineup includes several wall-mounted series, including the MIDEA35, 28, 25, and 22.
In Hemmingford, we selected the MIDEA35, the premium series in this product family, particularly well suited to a Quebec residence where the heat pump must continue providing heating when temperatures become decidedly wintry.
Why the indoor unit’s position is crucial
A wall-mounted unit should not simply be installed wherever there is a piece of empty wall left.
Before installation, we look at:
- the direction in which the air can be projected;
- the available height;
- obstacles located immediately in front of and below the unit;
- the ability to access the filters;
- future access to the internal components;
- the route required for the refrigerant lines;
- condensate drainage;
- the arrangement of the room’s furniture and permanent features;
- how the air will be able to circulate toward adjacent spaces.
In the photo of our job in Hemmingfordthe unit is positioned above a fixed structure that occupies a large part of the wall. Installing it too low would have brought the airflow closer to this structure and would also have made the overall installation look visually heavier. A high installation allows the airflow to move directly toward the living area.
This may seem like an aesthetic detail. In reality, it is primarily a functional decision.
A wall-mounted heat pump works well only if its air can circulate
The rated BTU capacity is never a guarantee that a room will be comfortable.
A heat pump can have excellent energy efficiency and still give the impression of uneven heating if its airstream immediately hits a cabinet, beam, partition, or large piece of furniture.
The MIDEA35 offers particularly fine airflow control. Midea states that its wall-mounted units can provide up to 100 air-volume settings, allowing the fan speed to be gradually adjusted to the room’s needs. The manufacturer also provides intelligent control through the SmartHome app and Wi-Fi, depending on the configuration.
In an installation like this, controlling the airflow becomes genuinely useful. The unit can operate at a low setting when the temperature is already close to the setpoint, then increase its airflow when greater demand arises.
A high installation does not mean that the unit should be right against the ceiling
We sometimes encounter installations where a wall-mounted heat pump has been mounted as high as physically possible solely to make it less visible.
That is not our approach.
The unit must always maintain the clearances required by its installation manual. The air intake of many wall-mounted units is located in their upper section. If this area does not have sufficient clearance, airflow may be impaired and opening the unit for maintenance may become more difficult.
The photograph shows the general position chosen in Hemmingford, but it obviously should not be used to measure the actual clearances. These are determined on site during installation.
The goal is to achieve a precise compromise: a discreet, well-positioned, accessible heat pump with adequate airflow.
A ductless installation particularly well suited to renovations
A concrete advantage of a wall-mounted heat pump is the limited amount of work required compared with adding a complete central system.
In its documentation, Midea explains that the indoor and outdoor units can be connected by refrigerant lines passing through a relatively small opening in the wall, without undertaking the demolition associated with installing a duct network.
For an existing home in Hemmingford, this feature can make all the difference. The walls, ceilings, and architectural elements already in place impose their own constraints. Our job is therefore to integrate the new system rather than unnecessarily transform the room to accommodate the machine.
MIDEA35: a series designed for heating in very low temperatures
The name MIDEA35 corresponds to Midea’s premium wall-mounted series marketed as a heat pump for very cold climates.
According to the technical documentation provided, the series operates in heating mode down to -30 °C and uses the refrigerant R-454B, classified as A2L. It is offered in three nominal cooling capacities: 9,000, 12,000, and 18,000 BTU/h.
Here are the main published figures:
| MIDEA35 | 9,000 BTU | 12,000 BTU | 18,000 BTU |
|---|---|---|---|
| Rated cooling | 9,000 BTU/h | 12,000 BTU/h | 18,000 BTU/h |
| Rated heating | 12,000 BTU/h | 12,000 BTU/h | 20,000 BTU/h |
| SEER2 | 33,3 | 29,4 | 25,6 |
| HSPF2 IV | 22,0 | 14,5 | 16,2 |
| Heating at -15 °C | 13,500 BTU/h | 13,500 BTU/h | 22,600 BTU/h |
| AHRI | 215471386 | 215471387 | 215471388 |
These figures are important because they show why we do not judge a heat pump solely by the number in its commercial name. Performance varies according to the exact combination of the indoor and outdoor units.
Why we do not invent the exact capacity of this project
The photograph confirms the presence of a MIDEA35, but it does not allow us to read the nameplate precisely enough to confirm whether this particular installation is a 9,000, 12,000, or 18,000 BTU version.
We therefore prefer to retain accurate information rather than arbitrarily assigning a capacity to the project.
This is also a valuable lesson for homeowners shopping for a heat pump: the commercial series is not sufficient to compare two quotes. You need the complete model numbers for the indoor and outdoor units, as well as the corresponding AHRI number.
Up to 33.3 SEER2: what this efficiency really means
The most efficient version of the MIDEA35 reaches 33.3 SEER2 in cooling. The manufacturer also indicates up to 22.0 HSPF2 in heating.
These values are particularly high for a wall-mounted heat pump, but we always emphasize one point to our clients: high performance on paper does not compensate for poor capacity selection.
An oversized machine is not automatically a better machine.
We assess factors including floor area, insulation, windows, sun exposure, heat loss, ceiling height, and room layout before determining the appropriate capacity.
In Hemmingford as in Montreal, Laval, Longueuil, on the North Shore or on the South Shore, this sizing step is essential to allow variable-speed technology to do its job properly.
Variable-speed technology changes the comfort experience
Older units that operate mainly through on-off cycling tend to create greater fluctuations: full capacity, shutdown, a new demand, and restart.
The MIDEA35 uses variable-speed technology. The compressor can adjust its operation according to the heating or cooling demand. Midea emphasizes that this modulation reduces temperature fluctuations and promotes a more stable indoor temperature.
In practical terms, when a room approaches the requested temperature, the system can reduce its output rather than simply shutting off.
This is particularly useful in a room occupied for long periods, because comfort often depends less on how quickly 21°C can be reached than on the ability to maintain 21°C without constantly alternating between too hot and too cold.
This Hemmingford project shows why installation details matter just as much as choosing the MIDEA35
Indoor airflow must match the actual space
The MIDEA35 does not have the same airflow depending on the selected capacity.
For the 9,000 and 12,000 BTU models, Midea indicates up to approximately 559 CFM in Turbo mode. The 18,000 BTU version reaches approximately 812 CFM. The physical dimensions of the indoor unit also increase: approximately 37.99 in. wide for the 9,000 and 12,000 BTU versions, compared with 44.88 in. for the 18,000 BTU version.
This difference matters greatly when an installation must be carried out in an architectural location as precise as the one shown in our photo.
We must check that there is sufficient width for the unit, but also consider access for opening, cleaning, potential part replacement, and airflow direction.
Quiet operation is particularly important for a unit installed in a living space
The indoor unit of a heat pump is generally much closer to occupants than the equipment of a central system.
Noise therefore becomes a concrete consideration.
Depending on the MIDEA35 combinations, Midea publishes indoor sound levels as low as 19 dB(A) for the 9,000 and 12,000 BTU models and up to 16 dB(A) for the 18,000 BTU version under certain operating conditions.
The series also includes a silent mode, which can be particularly appreciated in a living room, bedroom, office, or any other space where the unit operates for several hours at a time.
But once again, the equipment is only part of the result. Poorly executed mechanical installation, lines that transmit vibrations, or inadequate fastening can create noises that do not even come from the fan.
R-454B requires installation suited to A2L systems
The MIDEA35 uses R-454B. The documentation also mentions an A2L refrigerant leak detection sensor as well as an A2L dispersion system among the features of the product line.
For the homeowner, the refrigerant change may seem invisible. For the HVAC installer, it is not.
The work must be carried out using the procedures, tools, and practices appropriate for the system concerned. Refrigerant connections, drainage, leak testing, evacuation, and commissioning must comply with the manufacturer’s requirements and the type of refrigerant used.
This is one of the reasons why we strongly advise against comparing two installations based solely on the price of the unit.
The copper diameter changes according to capacity
Another very practical detail: not all MIDEA35 units use the same piping.
The versions 9,000 and 12,000 BTU versions use 1/4 in and 3/8 in, while the 18,000 BTU uses 3/8 in and 5/8 in. The published maximum lengths are 82 ft for the two smaller capacities and 164 ft for the 18,000 BTU model.
This becomes essential when replacing an older heat pump.
A common mistake is to choose a new unit and automatically assume that the existing copper lines can be reused. At AirGreen, we check the piping’s size, condition, routing, and compatibility before making that decision.
The same principle applies to the electrical circuit
The MIDEA35 series operates at 208/230 V, single-phase, 60 Hz.
The documentation specifies a minimum circuit ampacity of 16 A for the 9,000 and 12,000 BTU models, and 24.9 A for the 18,000 BTU model. The specified maximum overcurrent protections are respectively 20 A, 20 A, and 25 A.
When preparing a quote, we therefore do not determine the breaker based on a statement such as “it used to be 12,000 BTU.” We refer to the electrical specifications for the combination actually being installed.
That is an important difference between replacing a box on a wall and carrying out a professional HVAC installation.
Useful everyday features, not just a long list in a brochure
The MIDEA35 offers several features that homeowners can actually use:
- fan speed control from 1% to 100%;
- ECO mode;
- night mode;
- quiet mode;
- timer;
- function Follow Me;
- humidity control;
- horizontal and vertical swing;
- maintenance heating at 8°C;
- automatic cleaning;
- Wi-Fi control;
- 24 V interface available depending on the configuration;
- optional wired controller.
Midea’s documentation also describes a removable blower wheel to facilitate more thorough cleaning of the unit.
This last point is particularly important to us as contractors, because ease ofHVAC maintenance directly affects the system’s condition after several years.
A wall-mounted heat pump gradually accumulates dust and contaminants on its filters, coil, fan, and drain pan. A unit designed to provide easy access to these components is easier to maintain properly.
Follow Me function: when the temperature near the heat pump is not the temperature felt in the room
A heat pump installed high on a wall naturally measures a temperature in an area that may differ from what is felt lower down.
The Follow Me is therefore an interesting tool. The documentation indicates that the sensor built into the remote control can measure the ambient temperature so that the unit adjusts its operation based on this value.
In a room with a relatively high ceiling, temperature variations, or a heat pump installed far from the occupied area, this function can help fine-tune comfort.
However, the remote control must be left in a representative location. Placing it directly in sunlight, next to a cold window, or near another heat source would inevitably distort the reading.
LogisVert: verify the AHRI number before promising a rebate
For the MIDEA35 series, Midea publishes the following AHRI references:
- 215471386 for the 9,000 BTU combination;
- 215471387 for the 12,000 BTU combination;
- 215471388 for the 18,000 BTU combination.
These numbers are much more useful than a simple mention of “MIDEA35” when financial assistance needs to be verified.
For installations carried out since November 26, 2025, Hydro-Québec indicates that a heat pump must be ENERGY STAR certified to be eligible for the LogisVert program. Hydro-Québec also recommends verifying this using the AHRI number in its official list, since eligible models and amounts may change.
That is why we do not publish a specific rebate amount for this Hemmingford installation without having confirmed the exact capacity, the indoor/outdoor combination, and its eligibility on the actual installation date.
This caution is important. A manufacturer's brochure can confirm a heat pump's technical performance, but the program's official list remains the reference for financial assistance.
A particularly attractive warranty for the residential sector
The Midea brochure presents a 12-year limited warranty on the compressor, 12 years on parts, and 10 years on labor, in accordance with the terms of the applicable warranty program.
We always recommend keeping the installation documents:
- itemized invoice;
- indoor model number;
- outdoor model number;
- serial number;
- AHRI or ENERGY STAR reference;
- proof of registration when required.
This information becomes important for both a warranty claim and a rebate application or future service call.
The mistakes we want to avoid on a wall-mounted installation like the one in Hemmingford
This project is a good example of several points we systematically check at AirGreen.
Installing the unit based solely on aesthetics
A visually appealing location is not necessarily a good one. Airflow, clearances, and maintenance take priority over perfect symmetry.
Choosing BTUs based solely on floor area
Two homes with the same floor area can have very different needs. Insulation, windows, orientation, interior volume, and room layout change the heating and cooling load.
Neglecting condensate drainage
In cooling mode, the indoor unit removes moisture from the air. This water must be able to drain reliably and durably.
Automatically reusing the old copper lines
The required diameters depend on the capacity and model. The MIDEA35 is an excellent example, since the 9,000/12,000 and 18,000 BTU models do not use the same line sizes.
Forgetting access for cleaning
A wall-mounted heat pump installed in a place that is impossible to open or clean quickly becomes a maintenance problem.
Promising a rebate before checking AHRI
We prefer to confirm actual eligibility rather than turn a potential amount into a marketing promise.
What we take away from this MIDEA35 installation in Hemmingford
The final photograph looks simple: a white unit, neatly installed up high, with a discreet display and an interior space that remains visually orderly.
But behind this result are all the decisions that give an installation its value: location selection, height, airflow, refrigerant line routing, drainage, sizing, electrical supply, commissioning, and future accessibility.
The MIDEA MIDEA35 brings particularly interesting features for Quebec: heating operation down to -30 °C, variable-speed technology, refrigerant R-454B, performance ratings of up to 33.3 SEER2 and 22.0 HSPF2, precise fan control, and multiple capacities that allow the unit to be adapted to the building.
For us at AirGreen, the same logic applies to Hemmingford, Montreal, Laval, Longueuil, on the North Shore and the South Shore : a good heat pump deserves an installation designed specifically for the home in which it will operate.
It is this combination of technical selection, precise HVAC installation, and attention to building details that makes the system pleasant to use in July, reliable in January, and accessible when maintenance is required several years later.