Installation of a MIDEA MIDEA35 wall-mounted heat pump in L’Île-Cadieux, in Vaudreuil-Soulanges west of Montreal

A very clean interior installation where the positioning of the wall-mounted head and the piping finish made all the difference

At L’Île-Cadieux, we completed the installation of a MIDEA MIDEA35 wall-mounted heat pump in a residence where the interior result had to be as visually clean as it was effective from an HVAC standpoint. The photograph taken after our work shows a Midea unit installed very high on a light-coloured wall, near the ceiling, with an intentionally discreet finish and a short white finishing element beneath the unit to neatly organize the technical routing.

This project illustrates an aspect that is often underestimated when purchasing a heat pump: two installations of the same model can produce very different results depending on how the indoor head is positioned, levelled, connected, and integrated into the wall.

On a wall-mounted heat pump, the indoor unit is the part of the system that the homeowner sees every day. A few millimetres of difference, poorly organized piping, an appliance placed too low, or an unnecessarily bulky finish can completely change the appearance of the project.

At L’Île-Cadieux, our objective was therefore precise: to install the MIDEA35 in a position that promotes air circulation while maintaining a clean, compact appearance.

An indoor head installed near the ceiling to preserve the wall

The first visible characteristic in the photo is the unit’s height.

The Midea head occupies the upper part of the wall and leaves practically the entire area below available. In a residence, this way of positioning a heat pump offers a concrete advantage: it prevents the unit from conflicting with furniture, wall art, storage spaces, or other decorative elements.

However, the installation height should never be determined solely by aesthetics.

A wall-mounted unit draws in room air and circulates it through its heat exchanger before redistributing it throughout the room. The necessary clearances must therefore be maintained for proper operation and future access to the filters and components.

That is why, at AirGreen, we consider the following simultaneously:

• the ceiling clearance;
• the available wall width;
• the airflow direction;
• the piping route;
• access for theHVAC maintenance;
• the wall structure;
• the drainage location;
• the installation’s final appearance.

A properly selected but poorly positioned heat pump can lose some of its day-to-day benefits.

The detail beneath the unit: a technical finish that remains intentionally compact

Below the indoor unit visible in the photo, we can see a rectangular white element that organizes the technical routing beneath the unit.

This type of finish deserves more attention than one might think.

The refrigerant lines, communication wiring, and drainage must necessarily connect to the indoor unit. Depending on the building’s structure and the direction in which these elements need to run, the entire route cannot always be completely concealed inside the wall.

In this project, L’Île-Cadieux, we kept this transition short and clean instead of leaving the lines exposed.

The goal is not to hide the technical reality of the installation at all costs. It is to integrate it in an orderly manner.

The Midea brochure states that ductless systems use a relatively compact connection between the indoor and outdoor units and can be adapted to different spaces thanks to the flexibility of the refrigerant lines.

An installation that looks simple because the preparation was done correctly

In the final photograph, we see essentially a white indoor unit on a white wall.

This is precisely the desired result.

A good HVAC installation should not draw attention with misaligned lines, openings that are too large, or inconsistently installed accessories. The technical work should stand out mainly for its neatness.

Before permanently securing a wall-mounted indoor unit, we need to check:

1. the location of the bracket;
2. the mounting plate level;
3. the wall penetration position;
4. the direction of the lines;
5. the bend radius of the copper lines;
6. the drain orientation;
7. the electrical and communication connection;
8. the necessary clearance around the unit.

A mistake at the beginning of the project can become very difficult to correct once the unit is fully connected.

MIDEA35: Midea’s high-end wall-mounted series

The MIDEA35 belongs to the range of Midea ductless wall-mounted systems presented in the manufacturer’s Quebec documentation. The brochure includes the MIDEA35, 28, 25, and 22 series, among others.

For the MIDEA35, Midea uses the designation extreme heat pump and advertises heating operation down to -30 °C, with refrigerant R-454B and classification Cold Climate V6.1.

For a residence located in L’Île-Cadieux, in the Vaudreuil-Soulanges area, winter heating performance is particularly relevant. A heat pump in this region should not be selected solely to provide air conditioning in July. We need to consider how it performs when temperatures drop sharply.

Midea's published operating range extends down to -30°C in heating and up to 24°C at the other end of this range.

Three different capacities under the same name, MIDEA35

The name MIDEA35 refers to a series rather than a single capacity.

The documentation provided presents three combinations:

• 9,000 BTU/h for cooling;
• 12,000 BTU/h;
• 18,000 BTU/h.

The corresponding indoor units are the MSESU-H09B-2A, MSESU-H12B-2A and MSESU-H18B-2A. The associated outdoor units are the MO1SS-H09B-2A, MO1SS-H12B-2A and MO1SS-H18B-2A. The AHRI references are respectively 215471386, 215471387 and 215471388.

In the photo of this installation in L’Île-Cadieux, the label beneath the unit is visible, but its text is not legible enough to confirm the installed capacity unambiguously.

We therefore prefer not to arbitrarily assign a BTU rating to it.

This distinction is important for a homeowner comparing quotes. Two proposals simply listing “MIDEA35” may correspond to different capacities and performance levels.

Up to 33.3 SEER2, with performance specific to each combination

The MIDEA35 can reach 33.3 SEER2, but this value corresponds to the 9,000 BTU/h combination.

The manufacturer's data are as follows:

• 9,000 BTU/h: 33.3 SEER2;
• 12,000 BTU/h: 29.4 SEER2;
• 18,000 BTU/h: 25.6 SEER2.

For heating, the advertised HSPF2 Region IV values are 22,0, 14,5 and 16,2 respectively.

We consider this distinction particularly important during our consultations.

The maximum figure for a product range should never automatically be attributed to all its capacities. When a homeowner wants to compare two wall-mounted heat pumps, we recommend checking the model number and AHRI reference, not just the series’ commercial name.

In L’Île-Cadieux, the desired comfort depends as much on sizing as on installation quality

Heating capacity at -15°C provides very concrete information

A heat pump can operate down to a certain outdoor temperature while its capacity changes as the cold intensifies.

For this reason, we pay particular attention to performance data published for low temperatures.

At -15°C, Midea indicates for the MIDEA35 series:

• 13,500 BTU/h of rated heating capacity for the 9,000 BTU/h version;
• 13,500 BTU/h for the 12,000 BTU/h version;
• 22,600 BTU/h for the 18,000 BTU/h version.

The COPs indicated at this temperature are 3.60, 3.60 and 4.40.

These are data points that we consider much more useful than a simple claim such as “operates down to -30 °C.”

They provide a better understanding of what the heat pump can deliver when it actually has to heat a residence in cold weather.

Variable-speed technology for maintaining a more stable temperature

Midea’s documentation indicates that its variable-speed compressor adjusts its operation as temperature needs change.

Unlike a conventional system that frequently alternates between on and off, this modulation allows the heat pump to operate according to the actual load at any given time and reduce indoor temperature fluctuations.

This characteristic is especially meaningful when the appliance is properly sized.

An oversized heat pump does not automatically become better because it has more BTUs. Instead, we seek to establish a balance between the equipment’s capacity and the building’s heat losses or gains.

Why We Avoid Choosing BTUs Based Solely on Floor Area

Simplified rules such as “a certain number of square feet equals a certain number of BTUs” can serve as a starting point, but they are not sufficient for professional sizing.

We also take into account:

• insulation;
• the windows;
• sun exposure;
• the number of floors;
• whether the rooms have an open or closed layout;
• ceiling height;
• heat losses;
• the wall-mounted head’s location;
• the role of the existing heating system;
• the heat pump’s performance at low temperatures.

In a residence of L’Île-Cadieux, the size and configuration of the area actually served may matter more than the property’s total floor area.

Airflow: an aspect directly influenced by the head’s positioning

The MIDEA35 offers very fine ventilation adjustment.

Midea indicates up to 100 continuously adjustable air volume levels, as well as remote control through the SmartHome app and Wi-Fi when the corresponding features are available in the selected configuration.

At our L’Île-Cadieux installation, the unit’s high position makes it possible to take advantage of the head’s distribution capacity without unnecessarily occupying the wall.

However, airflow direction remains important.

We seek to avoid having a unit blow directly onto an obstacle located very close to its outlet or creating a very comfortable zone directly in front of the appliance while leaving the rest of the room less well served.

Sound levels suited to residential spaces

The stated indoor sound levels vary according to capacity and fan speed.

For the 9,000 and 12,000 BTU/h MIDEA35 combinations, the documentation indicates values as low as 19 dB(A) under the published quiet operating conditions. For the 18,000 BTU/h model, a value as low as 16 dB(A) is indicated.

Sound level is particularly important for a unit installed in a bedroom, relaxation area, office, or living space used for long periods.

A larger indoor unit does not necessarily indicate a better choice

Dimensions vary considerably within the series.

The 9,000 and 12,000 BTU/h versions measure approximately 37.99 in. wide, 9.41 in. deep, and 12.56 in. high.

The 18,000 BTU/h version is noticeably larger, at approximately 44.88 in. wide, 10.83 in. deep, and 14.57 in. high.

These dimensions must be confirmed before installation, particularly when the indoor unit must be placed above a window, between two openings, or near the ceiling.

In our project in L’Île-Cadieux, the way the unit fits into the wall shows precisely why we pay so much attention to measurements before work begins.

R-454B: the refrigerant circuit must match the new heat pump

The MIDEA35 operates with R-454B, an A2L-classified refrigerant.

Midea also indicates an A2L refrigerant leak detection sensor among the features associated with this product family.

Refrigerant line dimensions also depend on capacity.

For the 9,000 and 12,000 BTU/h versions, the published diameters are 1/4 in. for the liquid line and 3/8 in. for the gas line.

For the 18,000 BTU/h model, Midea specifies 3/8 in. and 5/8 in..

We always verify these dimensions before reusing an existing circuit in a replacement project.

An old line that is physically present in the wall is not automatically compatible with the new heat pump.

Up to 164 feet of piping, depending on the model

According to the provided technical specifications, the 9,000 and 12,000 BTU/h versions of the MIDEA35 allow a maximum length of 82 ft.

For the 18,000 BTU/h model, this length can reach 164 ft, with a published maximum height difference of 82 ft.

This flexibility can be useful when it is preferable to place the indoor unit in an area that optimizes comfort rather than directly in front of where the outdoor unit can be installed.

Comfort features integrated into the MIDEA35 range

The series offers many functions that we can explain to the homeowner during commissioning.

The documentation notably mentions:

• mode ECO;
• Turbo function;
• fan setting;
• night mode;
• timer;
• child lock;
• function Follow Me;
• automatic cleaning;
• silent mode;
• maintenance heating at 8 °C;
• horizontal swing;
• vertical swing;
• Wi-Fi control;
• smart sensor;
• humidity control.

The Follow Me function uses the temperature sensor built into the remote control to measure the temperature near it and allow the system to adjust its operation more precisely.

An interesting 8 °C maintenance function during an absence

For a property that is unoccupied during certain periods, the heating function at 8 °C may be useful.

The documentation indicates that, in heating mode, this minimum setting maintains a reduced temperature to help prevent freezing during a prolonged absence in cold weather.

For a residence located on L’Île-Cadieux, this feature may be particularly useful when a homeowner wants to avoid unnecessarily maintaining a normal residential temperature setting while the building is unoccupied.

Maintenance: the indoor unit’s design facilitates access

A good installation must also remain serviceable.

Midea indicates that, on the MIDEA35, 28, and 25 series, the blower wheel can be removed to allow a deep cleaning and make it easier to access the inside of the wall-mounted unit.

This design is particularly useful for more thorough cleaning than simply washing the filters.

Over the years, dust and other contaminants can accumulate on the evaporator, blower wheel, and certain interior surfaces. Proper maintenance helps preserve airflow and system cleanliness.

The errors this installation helps illustrate

Placing the head only where the exterior hole is easiest to make

We prefer to think first about the room’s airflow and comfort.

Letting the lines become the most visible element on the wall

A short, well-organized technical transition, as shown in our photo, provides a much neater finish.

Installing the unit without checking its upper access

The filters and certain components must remain accessible.

Confusing MIDEA35 with a single capacity

The series includes several combinations, with different dimensions and performance levels.

Choosing a capacity that is too high “to be sure”

Oversizing is not a guarantee of comfort. A selection suited to the building is preferable.

Promising a subsidy simply because the product is identified as cold-climate

The brochure provides the AHRI numbers and the MIDEA35 Cold Climate V6.1 classification. However, it does not by itself provide a financial assistance amount applicable to the L’Île-Cadieux project.

For LogisVert or another program, so we verify the exact combination and the criteria in effect at the time of the application before confirming eligibility or an amount.

A warranty worth considering in the system’s overall value

The Midea documentation provided for residential installations presents a 12-year limited warranty on the compressor, 12 years on parts and 10 years on labor, according to the terms applicable to the warranty program.

We always recommend that homeowners verify the warranty registration and retention requirements.

The best scenario is still equipment that is properly sized, correctly installed and maintained as needed.

An AirGreen installation designed to remain discreet for many years

The project in L’Île-Cadieux is a good example of an installation where the essential details matter.

The Midea indoor unit is installed high on the wall. Its alignment remains clean. The visible technical passage beneath the unit is short and orderly. Most of the wall remains open, and the entire system blends in without becoming the dominant element in the room.

This level of integration is what we seek in our wall-mounted heat pump.

Whether we work in L’Île-Cadieux, Montréal, Laval, Longueuil, the North Shore or the South Shore, we apply the same principles: select the right capacity, plan airflow, comply with the manufacturer’s requirements, organize the lines carefully and consider future maintenance from the moment of installation.

The MIDEA35 offers particularly impressive specifications, with efficiency reaching 33.3 SEER2, an HSPF2 of up to 22,0, heating operation down to -30 °C, R-454B refrigerant and several comfort control tools.

But a good heat pump truly delivers its value when it is installed in a suitable location and properly integrated into the building.

In L’Île-Cadieux, that is exactly what we sought to accomplish: a clean, compact and thoughtfully designed HVAC installationwhere MIDEA35 technology naturally integrates into the interior space instead of overwhelming it.