Installation of a MIDEA MIDEA35 wall-mounted heat pump in the Elgin neighborhood
AirGreen installation of a MIDEA35 wall-mounted heat pump in the Elgin neighborhood: outdoor unit on a metal bracket, long linesets protected along the brick façade, R-454B, and heating down to -30 °C.
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The job on one screen
The unit’s data sheet
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.
The article, chapter by chapter
An outdoor installation on a brick façade where the line routing becomes an essential part of the project
In the Elgin, this installation of a MIDEA MIDEA35 wall-mounted heat pump perfectly illustrates that an HVAC project is never limited to choosing the equipment. In an existing masonry building, the real challenge often consists of determining how to neatly connect the indoor and outdoor units while respecting the building’s architecture, openings, maintenance access, and the system’s technical constraints.
The photo of our AirGreen installation shows several particularly interesting elements. The building has a multi-level brick façade, with various windows and architectural projections. The Midea outdoor unit is installed up high on a robust metal wall bracket, rather than directly on the ground. Long vertical sections of white line covers were installed against the masonry to protect and conceal the lines connecting the different parts of the system.
This type of project requires much more preparation than an installation on a bungalow with a completely unobstructed exterior wall.
We need to determine a route that is:
- technically compatible with the heat pump;
- as direct as possible;
- visually organized;
- protected from the elements;
- accessible for future service;
- suited to an existing masonry façade.
It is precisely this planning work that makes it possible to achieve a clean, durable wall-mounted heat pump installation.
Why install the Midea outdoor unit up high?
In this installation in the Elgin neighborhood, the outdoor unit is mounted to the building on a metal structure.
This choice can be particularly relevant when ground space is limited or when it is preferable to keep the heat pump clear of snow accumulation, water, and obstacles near the foundation.
In our climate, the location of the outdoor unit is never simply an aesthetic choice.
A heat pump used for heating must be able to:
- draw in enough air;
- discharge air without obstruction;
- properly drain the water produced during defrost cycles;
- remain accessible for maintenance;
- operate without being buried by snow accumulation.
A wall-mounted installation on a bracket must also take into account the weight of the unit and the nature of the wall to which the structure is attached. On a brick façade like the one visible at this job site, selecting the anchor points and ensuring the strength of the mounting are particularly important.
A brick façade requires a different working method
Brick requires much more precision than simple lightweight siding.
Before drilling, we must consider the refrigerant route, the location of each outlet, and the visible consequences of drilling. An error of a few inches can force us to redo an opening or create an unnecessarily complicated route.
In the Elgin neighborhood, we therefore worked with the existing architecture rather than trying to ignore it.
The white outdoor conduits visible in the photograph follow long vertical lines. This arrangement produces a much more structured result than several short sections placed at different angles on the façade.
An outdoor line cover serves, among other things, to protect and group together:
- the copper refrigerant lines;
- insulation;
- certain communication cables;
- the drainage components when the configuration requires them.
On a large brick façade, its installation also becomes a visual element of the project. It is therefore important to seek a logical route that minimizes the impression of an afterthought installation.
The refrigerant route: a technical constraint that must never be improvised
A ductless heat pump connects its indoor unit to the outdoor unit with refrigerant lines. Midea's documentation also highlights the flexibility of this type of system and indicates that certain configurations can accommodate substantial piping lengths.
But this flexibility does not mean that all lengths or diameters are acceptable.
In the MIDEA35, the piping dimensions depend directly on the installed capacity.
For the versions 9,000 and 12,000 BTU, Midea specifies lines measuring 1/4 in. and 3/8 in.. For the 18,000 BTU, the dimensions increase to 3/8 in. and 5/8 in.. The maximum length specified by the manufacturer is 82 ft for the 9,000 and 12,000 BTU versions and 164 ft for the 18,000 BTU model.
These figures are particularly interesting when a building has several floors, like the one at our installation in the Elgin neighborhood.
They also explain why we must identify the exact combination before confirming a route.
MIDEA35: a heat pump designed for cold-weather heating
The series MIDEA35 is one of the manufacturer's high-end wall-mounted heat pumps.
Midea presents it as an extreme-climate heat pump, designed to operate in heating mode down to -30 °C. It uses the refrigerant R-454B, belongs to the A2L category and is associated with certification Cold Climate V6.1 in the manufacturer's documentation.
This is particularly important in a Quebec installation.
A heat pump is no longer chosen solely to provide cooling for a few weeks in the summer. Many homeowners now want to use their system as a true heating source for much of the winter.
The MIDEA35 has a published operating range of -30 °C to 24 °C in heating and -30 °C to 50 °C in cooling for the combinations in this series.
This low-temperature operating capability is a much more relevant consideration for our climate than the nominal BTU capacity alone.
Efficiency, sizing, noise, and maintenance: what you need to understand before choosing a MIDEA35
Three different capacities in the MIDEA35 series
The technical documentation indicates three main cooling capacities for this range: 9,000, 12,000, and 18,000 BTU/h.
The combinations are as follows:
9,000 BTU version
- indoor unit: MSESU-H09B-2A;
- outdoor unit: MO1SS-H09B-2A;
- AHRI number: 215471386;
- nominal cooling: 9,000 BTU/h;
- nominal heating: 12,000 BTU/h;
- SEER2: 33,3;
- HSPF2 IV: 22,0.
12,000 BTU version
- indoor unit: MSESU-H12B-2A;
- outdoor unit: MO1SS-H12B-2A;
- AHRI number: 215471387;
- nominal cooling: 12,000 BTU/h;
- nominal heating: 12,000 BTU/h;
- SEER2: 29,4;
- HSPF2 IV: 14,5.
18,000 BTU version
- indoor unit: MSESU-H18B-2A;
- outdoor unit: MO1SS-H18B-2A;
- AHRI number: 215471388;
- nominal cooling: 18,000 BTU/h;
- nominal heating: 20,000 BTU/h;
- SEER2: 25,6;
- HSPF2 IV: 16,2.
The exterior photo of our installation does not make the nameplate clear enough to confirm the exact installed capacity. We prefer not to arbitrarily assign a BTU rating to a project when the information is not visible.
This is also a good example of how a homeowner should compare two quotes: the name MIDEA35 is not enough. The exact combination and AHRI number matter.
Why sizing must be adapted to the building
We regularly encounter the idea that a larger unit will necessarily provide better comfort.
That is not how a properly sized HVAC system works.
A heat pump must match the building's load. In particular, we need to analyze:
- the heated area;
- heat loss;
- insulation;
- the number of windows;
- their orientation;
- the ceiling height;
- the layout of the rooms;
- the number of exterior walls;
- the floor where the indoor unit will be installed;
- the natural circulation of air between spaces.
A oversized heat pump can quickly reach the setpoint without benefiting as effectively from continuous, modulated operation. An undersized unit, on the other hand, may operate at high capacity for long periods.
Midea’s variable-speed technology allows the compressor to adjust its operation to thermal needs rather than simply switching between on and off. The manufacturer states that this modulation reduces temperature fluctuations and maintains more stable comfort.
Very high efficiency, but different depending on capacity
The figure 33.3 SEER2 associated with the MIDEA35 naturally attracts attention.
Nevertheless, it must be read correctly.
This maximum efficiency applies to the 9,000 BTU combination. The 12,000 BTU version shows 29.4 SEER2, while the 18,000 BTU model is rated at 25.6 SEER2.
All three remain high-efficiency units, but it is important not to advertise a product line’s maximum efficiency as though it automatically applied to every capacity.
At AirGreen, when we compare equipment for a project in Montreal, Laval, Longueuil, the North Shore, the South Shore or an area such as the Elgin neighbourhood, we always examine the exact combination.
A particularly low indoor sound level
Comfort is not measured only in degrees Celsius.
A wall-mounted heat pump installed in a living room, bedroom, or open-plan area may operate for several hours a day. Noise therefore becomes an important selection criterion.
Depending on capacity, Midea publishes indoor sound levels for the MIDEA35 that can drop as low as 19 dB(A) on the 9,000 and 12,000 BTU versions and up to 16 dB(A) for certain operating conditions of the 18,000 BTU model.
The installation also affects the acoustic result. An inadequate mounting or a line that transmits vibrations to the structure can create noise that the machine itself would not normally produce.
That is why we pay as much attention to the installation as we do to the unit itself.
The outdoor unit must remain accessible after installation
The wall bracket visible at our job site in the Elgin neighbourhood places the outdoor unit at a good height above the ground.
However, installing a heat pump high up also means considering its future maintenance.
A technician may eventually need to access the unit to:
- inspect the connections;
- check the fan’s operation;
- clean the heat exchanger;
- take electrical measurements;
- work on the refrigeration circuit;
- diagnose a problem.
We therefore avoid considering the installation complete simply because the unit physically fits in the available space.
A professional installation location must remain usable throughout the machine’s service life.
R-454B changes certain practices compared with older heat pumps
The MIDEA35 uses R-454B. The brochure also mentions a detection system associated with A2L refrigerants.
When a homeowner replaces an old heat pump, they should not assume that the work methods are identical to those used for an older system.
The following must be observed:
- refrigerant type;
- practices suitable for A2L;
- pipe diameters;
- length limits;
- refrigerant charge;
- vacuum procedures;
- leak tests;
- the model’s electrical requirements.
This development in the HVAC market makes choosing an experienced installer even more important.
Electrical supply: it also varies according to capacity
The MIDEA35 series operates at 208/230 V, single-phase, 60 Hz.
According to the documentation, the 9,000 and 12,000 BTU versions require a minimum allowable amperage of 16 A with maximum protection of 20 A. The 18,000 BTU model has a minimum allowable amperage of 24.9 A, with maximum protection of 25 A.
We therefore always check the power supply before confirming an installation.
The fact that a home already has a heat pump does not guarantee that its electrical circuit is compatible with the new unit.
Maintenance of the indoor unit was also taken into consideration
Midea indicates that the MIDEA35, MIDEA28, and MIDEA25 series feature a removable blower wheel to make more thorough cleaning of the inside of the unit easier.
This feature is useful in the long term.
Over the years, dust can accumulate on the filters, evaporator, blower wheel, and certain parts of the drainage system.
A good HVAC installation must therefore be designed so that a heat pump maintenance is still possible without having to dismantle building components.
Wi-Fi, airflow control, and comfort features
The series offers numerous control functions, including Wi-Fi control, night mode, quiet mode, a timer, horizontal and vertical oscillation, and the “Follow Me” function.
Midea also indicates up to 100 air volume control levels, allowing gradual fan speed adjustment. The SmartHome app can be used for remote control when the corresponding configuration is used.
For the owner, these features make the unit much more adaptable than an older wall-mounted air conditioner operating only at a few fixed speeds.
Rebates: always verify the exact combination
The AHRI references for the MIDEA35 series are clearly indicated in the manufacturer’s documentation.
This is essential information when the owner wants to check possible eligibility for a program such as LogisVert.
We always recommend confirming eligibility with:
- exact indoor unit number;
- outdoor unit number;
- AHRI number;
- installed capacity;
- the criteria in effect when the application is submitted.
A product range may include several capacities, and each combination has its own characteristics. The presence of the certification Cold Climate V6.1 is listed for the three MIDEA35 models presented in the brochure.
What this installation in the Elgin neighbourhood demonstrates about AirGreen’s work
The most interesting aspect of this installation is ultimately not just the heat pump.
It is its integration into the building.
We had a brick façade, several levels, different windows, limited ground space, and a relatively long route between the areas being served and the outdoor unit.
The visible result shows a Midea outdoor unit installed on a metal bracket, with the lines protected by long white trunking arranged in a structured manner against the façade.
This type of project reflects AirGreen’s approach exactly.
For every installation of a wall-mounted heat pump, we seek to strike a balance between:
- performance;
- reliability;
- accessibility;
- quality of finishing;
- pipe protection;
- outdoor unit location;
- integration into the building;
- ease of maintenance.
This method applies equally to our projects in the Elgin neighbourhood as with our heat pump installations in Montréal, Laval, Longueuil, on the North Shore and the South Shore.
A good machine can deliver excellent performance on paper. However, to maintain that performance for years, it must be paired with an installation suited to the building’s actual conditions.
In this project, MIDEA MIDEA35 offers a particularly interesting technical foundation with heating operation down to -30°C, R-454B refrigerant, high efficiency, variable-speed technology, and advanced control functions.
The rest of the work consists of providing it with the right conditions to operate properly.
The job tools
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.
How the job unfolds
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 we check on a job like this one
Each number is a point we check on site. Switch between summer and winter to watch air and heat move.
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.
Is your home ready?
Check what applies at your place. A "no" is not a refusal: it is what we sort out during the estimate.
Good habits, once the unit is in place
Six simple habits that keep the unit going. Your list stays on this device.
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.
The right pages, at the right time
Four statements: true or false?
It all comes down to details you have just seen.
1. In heating mode, the outdoor unit can produce water.
During defrost cycles. That water must drain away without forming ice.
2. You pick the capacity with a simple square-footage rule.
Windows, insulation, orientation and how the room is used all count. Capacity is chosen on site.
3. A multi-zone connects several indoor heads to a single condenser.
One head per room, all on the same condenser. Each room keeps its own temperature.
4. The disconnect can sit behind the patio furniture.
It must stay accessible: it is what shuts the unit off for service.
0 / 4 right answers
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?
Where does the outdoor unit go?
Are there grants?
Do I need a permit?
How cold can it heat?
How much can I save?
How is the LogisVert assistance calculated?
Is it noisy?
The outdoor unit is covered in ice: is that normal?
Does AirGreen hold the required licences?
Is the estimate free?
No question matches. Write to us: we answer.
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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).