Installation of a MIDEA MIDEA35 wall-mounted heat pump in Saint-Jacques-le-Mineur, on the South Shore
In Saint-Jacques-le-Mineur, AirGreen installs a MIDEA35 wall-mounted heat pump above an interior opening: precise positioning, heating down to -30 °C, and comfort tailored to the space.
In summer, the outdoor unit rejects the house's heat outside.
Generic illustration of this type of installation, not a survey of this job site. Tap a number.
Mounted level on a wall plate, high enough for the air to reach the whole room, with enough space around it to slide the filters out easily.
The refrigerant lines, the communication cable and the drain go through the wall in a single opening, sealed against water, cold air and insects.
Two insulated copper pipes connect the two units. Outside, a line cover can protect them from sun, knocks and weather.
A shut-off switch near the outdoor unit isolates it safely for service. It must stay accessible at all times.
The compressor and the fan. In heating mode it captures heat from the outdoor air, even in winter, and moves it inside.
On the ground or on the wall, it keeps the unit above accumulated snow. The unit stays clear and defrost water can drain away.
The fan needs to blow freely. Storage, a fence or a wall too close, and efficiency drops while noise goes up.
An indoor installation where the heat pump’s positioning makes all the difference for comfort
In Saint-Jacques-le-Mineur, this installation of a MIDEA MIDEA35 wall-mounted heat pump shows an aspect of HVAC work that is sometimes underestimated: the exact location of the indoor unit can be just as important as the choice of the heat pump itself.
In the photo taken after installation, the Midea wall-mounted unit is positioned very high on the wall, above a large interior opening, in a space where it would have been difficult to use the lower wall surfaces without compromising the room’s layout. The unit therefore makes use of a portion of the wall that would otherwise be unused, while keeping the entire air outlet area unobstructed.
The digital display visible in the center of the unit indicates 68, and the lower louvers are open, showing the unit operating at the time of the photo. The configuration allows the treated air to be projected toward the occupied space rather than directly against a piece of furniture or partition located a few centimeters away.
At AirGreen, this is exactly the kind of detail we study before a wall-mounted heat pump installation in Saint-Jacques-le-Mineur, Montreal, Laval, Longueuil, on the North Shore or the South Shore : where should the indoor head be placed to achieve effective air circulation, preserve living space, and make the installation as discreet as possible?
The Midea line of wall-mounted systems is specifically designed for ductless installations and includes the series MIDEA35, MIDEA28, MIDEA25, and MIDEA22.
Why install the unit so high on the wall?
A wall-mounted heat pump must be able to draw room air in through its upper section, process it through its heat exchanger, and then redistribute it through the lower louvers.
In this installation of Saint-Jacques-le-Mineurthe space available above the opening was a particularly interesting area. The unit does not take up a wall that could be used for a piece of furniture, storage, or other design elements. Its elevated position also promotes air distribution over a greater distance.
The manufacturer specifically plans several air-flow management functions for the MIDEA35 series, including:
- adjustable fan speed from 1% to 100%;
- horizontal swing;
- vertical swing;
- quiet mode;
- Turbo mode;
- “Follow Me” function;
- night mode;
- 8°C heating;
- timer;
- automatic cleaning;
- Wi-Fi control;
- smart sensor.
These features are among the functions announced for the MIDEA35, 28, and 25 series.
The unit’s physical position and these adjustment options must nevertheless work together. Even a heat pump with excellent airflow control will not perform to its full potential if its airflow is blocked by a cabinet or directed into a corner without circulation.
The particular challenge of a unit located above an opening
In this installation, the indoor head is located in a relatively narrow space between the ceiling and the top of the opening.
This requires precise planning.
We must maintain the necessary clearance above the appliance so that air can enter the unit properly. There must also be enough space around the heat pump to allow servicing, filter removal, and access to the components when necessary.
Visual alignment also matters. When a unit is installed above an opening or door, a difference in level quickly becomes noticeable. We therefore pay close attention to leveling the wall plate before the final installation of the indoor head.
Finally, the routing of the refrigerant lines, communication cable, and condensate drain must be planned from the outset. These are invisible elements in the final photo, but they largely determine the reliability of the installation.
A ductless installation suited to renovations and existing buildings
One of the major advantages of a ductless wall-mounted heat pump is precisely the ability to add heating and cooling without building a complete ductwork system in the walls or ceilings.
Midea indicates that the indoor unit can be connected to the outdoor unit through a relatively small opening, avoiding the major demolition, repair, or painting work associated with adding traditional ductwork.
In an existing residence in Saint-Jacques-le-Mineur, this advantage can be particularly valuable. We often have to work around:
- walls that have already been finished;
- finished ceilings;
- spaces where no ductwork exists;
- unusual room layouts;
- furniture constraints;
- exterior walls available only in certain locations.
A wall-mounted heat pump gives us more flexibility to build a solution around the building rather than requiring the building to undergo major renovations.
MIDEA35: a series, not a 35,000 BTU capacity
The name MIDEA35 can easily be interpreted as a 35,000 BTU heat pump. That is not the case.
MIDEA35 refers to the premium wall-mounted series from Midea. The technical brochure currently provided lists three rated cooling capacities:
| MIDEA35 model | Rated cooling | Rated heating | SEER2 | HSPF2 IV | AHRI |
|---|---|---|---|---|---|
| MSESU-H09B-2A / MO1SS-H09B-2A | 9,000 BTU/h | 12,000 BTU/h | 33,3 | 22,0 | 215471386 |
| MSESU-H12B-2A / MO1SS-H12B-2A | 12,000 BTU/h | 12,000 BTU/h | 29,4 | 14,5 | 215471387 |
| MSESU-H18B-2A / MO1SS-H18B-2A | 18,000 BTU/h | 20,000 BTU/h | 25,6 | 16,2 | 215471388 |
These values come from the technical table for the MIDEA35 series presented on page 10 of the Midea brochure.
The installation photo in Saint-Jacques-le-Mineur does not show the nameplate clearly enough to determine with certainty which of these three indoor/outdoor pairs was installed. We therefore prefer not to artificially assign a BTU capacity to the unit based solely on its visual dimensions.
This is also a useful lesson for a homeowner comparing quotes: the series name is not enough. You need to look at the exact indoor unit number, outdoor unit number, and corresponding AHRI combination.
Up to 33.3 SEER2: why efficiency varies by capacity
The MIDEA35 is advertised with efficiency of up to 33.3 SEER2, but this maximum value applies to the 9,000 BTU configuration.
The 12,000 BTU version is listed at 29.4 SEER2, while the 18,000 BTU version is rated at 25.6 SEER2HSPF2 values also vary by model.
This is an important distinction when comparing two heat pumps in Saint-Jacques-le-Mineur or elsewhere on the South Shore.
A large number printed on a brochure often represents the maximum performance of an entire series. The exact performance of the installed equipment must always be verified based on the specific combination of units.
Variable-speed technology improves comfort in an occupied room
The Midea series uses variable-speed compressor technology. Rather than operating only at full capacity and then stopping completely, the system can modulate its operation according to demand.
Midea explains that this modulation reduces temperature fluctuations and helps maintain a more stable environment than conventional on-off operation.
In a space like the one photographed in Saint-Jacques-le-Mineur, this means that the heat pump can operate gradually to maintain the setpoint rather than continuously sending large bursts of warm or cool air.
This operating method particularly improves comfort when the unit serves an area used daily.
Highly precise indoor fan control
Midea claims up to 100 air volume adjustment levels for its wall-mounted units, as well as remote control through the SmartHome app and Wi-Fi when the feature is available.
This feature is particularly interesting with a high-mounted installation like this one.
When a unit is installed near the ceiling, we can direct its louvers and adjust its speed to promote gradual air circulation throughout the room. The homeowner can then adjust the airflow according to the conditions:
For a quick temperature increase
A higher speed or Turbo mode can help reach the desired temperature more quickly.
To maintain the temperature
A moderate or low speed generally allows for quieter operation once the room has stabilized.
For nighttime use
Night mode and reduced fan speeds are better suited when noise level becomes a priority.
A heat pump designed to operate down to -30 °C
For the climate of Saint-Jacques-le-Mineur, winter performance is obviously a central consideration.
The series MIDEA35 is rated to operate in heating mode down to -30 °C. It is also identified as Cold Climate V6.1 and uses the refrigerant R-454B.
Its published heating operating range is from -30 °C to 24 °C.
However, it is important not to confuse “operation down to -30 °C” with “maintaining rated capacity down to -30 °C.”
As with any heat pump, available capacity and efficiency vary with outdoor temperature. Sizing must therefore be determined based on the building's actual heating requirements.
At AirGreen, we do not simply select a capacity by applying a rough rule based on the number of square feet. We consider, among other factors, the layout of the spaces, insulation, windows, heat loss, and how air can circulate from one room to another.
The technical details behind a reliable MIDEA35 installation in Saint-Jacques-le-Mineur
Drainage is particularly important with a unit installed high up
In cooling and dehumidification mode, the indoor unit removes moisture from the air. This moisture condenses on the coil and then must be removed through the drain.
When the installation is located above an interior opening, we must plan this route particularly carefully.
A gravity drain must maintain an appropriate slope. An incorrect slope, a pinched pipe, or an improperly positioned drain can cause water to back up or leak indoors.
The customer mainly sees the finished wall-mounted unit. On our end, we need to consider what happens behind the unit and inside the wall over several years.
The refrigerant lines vary depending on the selected MIDEA35
The 9,000 and 12,000 BTU models use lines measuring 1/4 in. liquid and 3/8 in. gas. The 18,000 BTU configuration, on the other hand, requires 3/8 in. liquid and 5/8 in. gas.
The maximum published length is 82 feet for the 9,000 and 12,000 BTU configurations, and 164 feet for the 18,000 BTU configuration.
This detail becomes important during a replacement.
We regularly encounter existing installations where an owner wishes to keep the old lines. Before saying yes, the following must be checked:
- their diameter;
- their condition;
- their length;
- their compatibility with the new unit;
- how they were installed;
- their accessibility for leak testing.
A new heat pump should never be chosen solely because its connections “seem to fit” an older installation.
R-454B requires installation suitable for A2L equipment
The MIDEA35 operates with R-454B, an A2L-class refrigerant.
The brochure also indicates a A2L refrigerant leak detection sensor and, for the MIDEA35, 28, and 25 series, an associated dispersion system.
For us, this means that installation procedures must follow the requirements established for this generation of equipment.
Preparing the lines, ensuring tightness, evacuating the system, making the connections, and commissioning are not secondary steps. They are what distinguish a machine simply mounted on the wall from a properly installed HVAC system.
Sound level: particularly important for a unit near living spaces
The MIDEA35 indoor head is designed to operate quietly when its speed decreases.
Depending on the capacity, the documentation indicates indoor sound levels that can drop as low as 19 dB(A) on the 9,000 and 12,000 BTU models and up to 16 dB(A) on the 18,000 BTU configuration under the conditions specified by the manufacturer.
In a room where the unit is visible and relatively close to the occupants, this type of low-speed operation can be particularly appreciated.
However, it is important to distinguish the unit's normal operating noise from vibrations that may result from improper installation. A properly secured, level, and connected indoor head prevents minor extraneous noises that become much more noticeable in the evening.
A design that also simplifies HVAC maintenance
A wall-mounted heat pump works by continuously passing room air through the unit. The filters and internal components therefore gradually accumulate dust and contaminants.
The MIDEA35 series includes washable filters and a removable fan wheel, designed to allow more thorough cleaning of the inside of the unit.
This feature is useful in the long term.
A HVAC maintenance should not be limited to quickly vacuuming the filters. Depending on the condition of the unit, the evaporator, fan wheel, condensate pan, and drainage may also need attention.
The fact that this unit is installed high up also underscores why we consider future accessibility from the outset of the initial installation.
“Follow Me” function: a temperature measured closer to the user
A particularly relevant feature in spaces where the temperature is not perfectly uniform is the “Follow Me”.
Midea documentation indicates that the sensor located in the remote control can measure the ambient temperature and allow the unit to adjust its operation based on this measurement.
This is useful when the indoor head is installed near the ceiling, because the temperature near the unit may differ from what is felt lower down in the room.
Warm air naturally rises. In winter, a sensor located only in the unit could therefore detect a temperature slightly different from what the occupants feel. The “Follow Me” function provides an additional way to manage this situation.
What we recommend to homeowners before a similar installation
For a wall-mounted heat pump in Saint-Jacques-le-Mineur, Longueuil, Montreal, Laval, on the North Shore or the South Shore, several simple checks can prevent future problems.
-
Do not choose the location based solely on aesthetics.
You need to plan for air intake, air discharge, the drain, lines, and maintenance. -
Do not choose capacity based solely on square footage.
Insulation, room distribution, and heat loss are just as important. -
Verify the exact model numbers.
MIDEA35 is a series; capacities and performance vary depending on the selected combination. -
Consider maintenance before securing the unit.
A unit that cannot be opened properly becomes much more difficult to clean. -
Do not neglect drainage.
A fully functional heat pump can still cause damage if its condensate drain is poorly designed. -
Verify the AHRI combination for any financial assistance program application.
The AHRI references listed for the MIDEA35 series are 215471386, 215471387, and 215471388, depending on capacity.
Rebates: never rely solely on the MIDEA35 name
The certification Cold Climate V6.1 and the AHRI numbers for the MIDEA35 are important information when a homeowner wants to verify potential eligibility for a rebate program.
However, the Midea brochure does not provide a rebate amount for this particular installation in Saint-Jacques-le-Mineur.
We therefore need to verify the exact indoor/outdoor unit combination, the corresponding AHRI number, and the program criteria applicable at the time of application.
This is an important distinction: two heat pumps bearing the same commercial name may not have exactly the same performance or the same AHRI reference.
An appealing residential warranty, but it must always be validated according to the applicable terms
Midea’s brochure presents a 12-year limited warranty on the compressor, 12 years on parts, and 10 years on labor.
As with any manufacturer’s warranty, the equipment registration and applicable terms must be verified at the time of purchase.
We always recommend keeping:
- the installation invoice;
- the indoor unit’s serial number;
- the outdoor unit’s serial number;
- the model numbers;
- the registration documents;
- the AHRI combination when relevant.
What this installation in Saint-Jacques-le-Mineur illustrates particularly well
The most interesting aspect of this project is not just the technical specifications of the MIDEA MIDEA35. It is its integration into a real space.
In the photo, the indoor unit occupies precisely the upper portion of the wall above an opening. It keeps the lower space clear, its airflow is not blocked, and its display remains visible from the room.
This is the type of installation where a few inches can change the result.
Too high, and maintenance access could become unnecessarily difficult. Too low, and it would encroach on the opening. Too close to the ceiling, its air intake could be restricted. Poorly centered, the whole installation would look improvised.
Our job is therefore to find that balance before drilling or fastening anything.
AirGreen: heat pump installations adapted to the building, not just the catalog
We install Midea wall-mounted heat pumps and other HVAC systems in Saint-Jacques-le-Mineur, Montreal, Laval, Longueuil, on the North Shore and the South Shore.
We consider choosing the equipment and choosing its location to be two parts of the same task.
An excellent heat pump that is improperly sized or positioned can produce disappointing results. Conversely, equipment selected according to the building’s actual needs and installed with particular attention to airflow, drainage, line routing, and accessibility can provide much more consistent comfort.
This installation of the MIDEA35 in Saint-Jacques-le-Mineur is a good example: an indoor unit integrated into a limited wall space, positioned above an opening without sacrificing living space, and commissioned to provide heating and cooling from a location that makes smart use of the existing architecture.
How it goes, from the first call to the end
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
Model, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
Floors and furniture protected, wall plate position marked level, wall opening located.
A single opening, with the slope the drain needs to flow outside.
Set on a stand raised above the snow, with the clearances the manufacturer requires.
Connected, insulated and protected. The opening is then sealed against water, cold air and insects.
A dedicated circuit and an accessible disconnect near the outdoor unit.
Leak test, vacuum, then start-up and a check of heating and cooling.
Remote, modes, filters: we show you the essentials before we leave.
- The on-site estimateWe look at the room, the outside wall, the line route and where the outdoor unit will go. That is where the capacity gets chosen.
- The quoteModel, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
- Getting readyFloors and furniture protected, wall plate position marked level, wall opening located.
- The wall openingA single opening, with the slope the drain needs to flow outside.
- The outdoor unitSet on a stand raised above the snow, with the clearances the manufacturer requires.
- Lines, cable and drainConnected, insulated and protected. The opening is then sealed against water, cold air and insects.
- The electrical workA dedicated circuit and an accessible disconnect near the outdoor unit.
- Tests and start-upLeak test, vacuum, then start-up and a check of heating and cooling.
- The walkthroughRemote, modes, filters: we show you the essentials before we leave.
What the unit delivers when it is cold
The range as published on airgreen.ca: pick a size to see its capacity in deep cold.
| Size | Heating at −8 °C | Heating at −15 °C | Coldest certified point | COP at −15 °C | SEER | HSPF | Indicative LogisVert aid |
|---|---|---|---|---|---|---|---|
| Midea Série 35 9 000 | 11,000 | 13,500 | −30 °C: 7,500 | 2.0 | 33.3 | 14.6 | – |
| Midea Série 35 12 000 | 11,000 | 13,500 | −30 °C: 7,500 | 2.0 | 29.4 | 12.7 | $1,320 |
| Midea Série 35 18 000 | 19,300 | 22,600 | −30 °C: 11,900 | 2.34 | 25.6 | 16.2 | $2,316 |
According to NEEP, its certified maximum capacity at −30 °C (−22 °F) is 7,500 BTU/h, 83% of its nominal 9,000 BTU size.
At 8 °C, its certified maximum capacity reaches 17,200 BTU/h, 91% more than its nominal 9,000 BTU size.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 13,500 BTU/h, 150% of its nominal 9,000 BTU size. Its COP there is 2.00.
According to NEEP, its certified maximum capacity at −30 °C (−22 °F) is 7,500 BTU/h, 62% of its nominal 12,000 BTU size.
At 8 °C, its certified maximum capacity reaches 17,200 BTU/h, 43% more than its nominal 12,000 BTU size.
According to NEEP, its certified heating capacity at −15 °C (5 °F) is 13,500 BTU/h, 112% of its nominal 12,000 BTU size. Its COP there is 2.00.
According to NEEP, its COP at −15 °C is 2.34: the highest of the Série 35 line, which ranges from 2.00 to 2.00 at that temperature.
According to NEEP, its certified maximum capacity at −30 °C (−22 °F) is 11,900 BTU/h, 66% of its nominal 18,000 BTU size.
At 8 °C, its certified maximum capacity reaches 29,700 BTU/h, 65% more than its nominal 18,000 BTU size.
Data read live from the airgreen.ca page of each size (NEEP / AHRI certified performance). When the title names the installed size, it is highlighted; otherwise the whole range is shown. The aid shown is today’s, using Hydro-Québec’s rule ($120 per 1,000 BTU/h at −8 °C); amounts quoted in the article date from its publication. Only Hydro-Québec confirms the assistance granted.A dash in the aid column: amount to be confirmed for this model.
And at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
Baseboards and electric furnaces turn 1 kWh of electricity into 1 kWh of heat. A heat pump delivers more: that is its COP. At Hydro-Québec’s rate D (11.142¢/kWh above 40 kWh a day, since 1 April 2026):
Hydro-Québec: a heat pump can be up to three times more efficient than baseboards for heating in the colder months.
Estimate per kWh of heat, at the chosen temperature, using the certified COP from the product page. Taxes, access charge and backup heat not included.
Conversion: 1 W = 3.412 BTU/h. An indication, not a load calculation: baseboards and furnaces are often stronger than the real need, and they can stay as backup. AirGreen confirms the capacity on site.
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Clean the indoor unit's filters.
- Clear leaves and debris left on the outdoor unit by winter.
- Test cooling before the first hot days.
- Clean the filters more often when the unit runs a lot.
- Keep plants away from the outdoor unit.
- Check that no water drips from the indoor unit.
- Rake the leaves around the outdoor unit.
- Test heating before the first cold days.
- Book periodic maintenance before winter.
- Keep snow away from the stand and the front of the unit.
- Let the unit defrost: it is normal.
- Never hit the ice on the fins; call us if the unit stays iced up.
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What people ask us about this kind of work
Does a wall-mounted heat pump heat in winter?
Wall-mounted or multi-zone: how do I choose?
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How cold can it heat?
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The outdoor unit is covered in ice: is that normal?
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Text and photo: a real AirGreen Climatisation & Chauffage job. The diagrams are generic illustrations of the type of installation, not a survey of this job site. Sources of the added figures: airgreen.ca product pages (NEEP / AHRI performance), Hydro-Québec (Heat pumps page, LogisVert, read on 13 October 2026), Régie de l’énergie (rate D as of 1 April 2026).