Installation of a MIDEA MIDEA35 wall-mounted heat pump in Salaberry-de-Valleyfield
In Salaberry-de-Valleyfield, AirGreen installs a MIDEA35 wall-mounted heat pump between two windows: clean integration, heating down to -30 °C, R-454B, and efficiency of up to 33.3 SEER2.
Take a tour of the installation
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.
In Salaberry-de-Valleyfield, a MIDEA35 integrated into a passageway wall between two openings
This MIDEA MIDEA35 wall-mounted heat pump installation in Salaberry-de-Valleyfield features a particularly interesting detail: the indoor unit had to be integrated into a section of wall located between two openings, one of which provides access to a staircase. The available space was therefore limited, and the heat pump’s position had to be carefully considered in relation to traffic flow through the house as well as thermal comfort.
In the photo of the completed installation, the Midea unit is installed high up, near the ceiling, on a beige wall bordered by two white door frames. No bulky line-hide cover is visible on the photographed façade. The overall installation remains clean and relatively discreet despite the unit’s central position in this passageway.
At AirGreen, this type of configuration is particularly interesting to us because it shows that a professional HVAC installation does not consist solely of finding a wall that is wide enough. We must analyze how the air will leave the heat pump, which rooms it can reach, the obstacles present, access for maintenance, the routing of the refrigerant lines, and the drainage of condensate.
At Salaberry-de-Valleyfield, this section of wall was located at a strategic point for interior circulation. A properly positioned unit in this location can use the natural movement of air through the openings to help maintain the comfort of several areas, depending on the actual layout of the rooms.
A wall between two doors: little space wasted, but several technical constraints
Install a wall-mounted heat pump between two openings can be highly effective, provided the work is properly planned.
In particular, we need to check:
- the available width between the frames;
- the location of the studs behind the drywall;
- the clearance from the ceiling;
- the space required to open the front panel;
- the possibility of removing the filters;
- the airflow direction;
- the drain route;
- the route for the copper piping and wiring;
- the position of equipment and controls already present on the wall.
The photograph also shows a wall-mounted control device beneath the unit, on the right. Without the exact reference for this device, we do not automatically identify it as a MIDEA35 control. However, the Midea range includes various control solutions, including a optional wired control and a 24 V interface depending on the configuration.
This distinction is important: in an existing installation, several heating or control systems may coexist on the same wall.
A high installation that keeps both passageways completely clear
The chosen position avoids encroaching on the door frames while preserving movement between the rooms.
This is particularly important in a hallway, landing, or area near a staircase. A unit that is too low could become visually obtrusive or blow directly on someone as they move from one room to another.
At a high setting, we can use the reach of the air jet to send treated air farther into the space.
Midea's documentation specifically indicates that its wall-mounted units offer very precise airflow control, with up to 100 adjustable air-volume levels, as well as smart control through the SmartHome app and Wi-Fi, depending on the configuration.
The ability to finely adjust the fan is useful in a circulation area: the goal is not necessarily to feel a strong draft, but to maintain a stable temperature in the areas served.
A ductless heat pump well suited to existing homes
The MIDEA35 is part of Midea's ductless wall-mounted heat pump systems. This type of equipment makes it possible to create a heating and cooling zone without having to build a complete network of ducts in the walls and ceilings.
Midea explains that the indoor unit connects to the outdoor unit through refrigerant lines passing through a relatively small opening. This design offers greater flexibility in renovations and in homes without a central ventilation network.
In an existing property Salaberry-de-Valleyfield, this advantage is tangible. We can work with the architecture that is already there rather than transforming several rooms solely to install the HVAC system.
The MIDEA35: three capacities and a cold-climate design
The MIDEA35 is presented in the manufacturer's documentation as a premium wall-mounted series using the refrigerant R-454B.
The three documented combinations can operate in heating mode down to -30°C and bear the certification Cold Climate V6.1 indicated by Midea.
The range includes:
| Version | Rated cooling | Rated heating | SEER2 | HSPF2 IV | AHRI |
|---|---|---|---|---|---|
| MIDEA35 9,000 | 9,000 BTU/h | 12,000 BTU/h | 33,3 | 22,0 | 215471386 |
| MIDEA35 12,000 | 12,000 BTU/h | 12,000 BTU/h | 29,4 | 14,5 | 215471387 |
| MIDEA35 18,000 | 18,000 BTU/h | 20,000 BTU/h | 25,6 | 16,2 | 215471388 |
At -15 °C, the published rated heating capacities are 13,500 BTU/h for the 9,000 and 12,000 BTU versions and 22,600 BTU/h for the 18,000 BTU version.
Why we do not claim to identify BTU solely from the photo
The unit is clearly visible in the photograph, but the plate beneath the unit is not legible enough for us to confirm the exact capacity unambiguously.
We therefore prefer not to arbitrarily assign 9,000, 12,000, or 18,000 BTU to this project.
This method also reflects our fieldwork: to inspect a heat pump, we use the complete indoor model number, outdoor model, and AHRI reference rather than relying solely on its appearance.
The heat pump's size matters particularly between two openings
On a large, unobstructed wall, a few extra inches may sometimes make no difference. In this installation, Salaberry-de-Valleyfield, physical dimensions become much more important.
The MIDEA35 versions 9,000 and 12,000 BTU have published interior dimensions of approximately:
37.99 in. wide × 9.41 in. deep × 12.56 in. high.
The version 18,000 BTU measures approximately:
44.88 in. × 10.83 in. × 14.57 in.
That represents nearly seven inches of difference in width.
When the unit must fit between two frames, as in this project, selecting the capacity before precisely measuring the space could lead to an unpleasant surprise.
We therefore verify the heating capacity and the physical dimensions before installation.
Variable-speed technology that promotes stability
The MIDEA35 uses variable-speed compressor technology.
Unlike a unit limited to a succession of full-power/stop cycles, the system can adjust its operation to the actual demand.
Midea states that this modulation helps reduce temperature fluctuations and maintain a more stable indoor environment.
In an area near several passageways, this modulation is particularly valuable. When doors are open, air moves toward a staircase, or several rooms are connected, the load experienced by the heat pump can vary.
A variable-capacity system can respond to these changes much more gradually.
The details hidden behind this MIDEA35 installation in Salaberry-de-Valleyfield
BTU should never be chosen simply based on floor area
A common mistake is to look only at the square footage and immediately select a capacity.
For a wall-mounted heat pump, we also consider:
- insulation quality;
- number of windows;
- building orientation;
- ceiling height;
- number of floors;
- staircase location;
- door placement;
- actual air circulation;
- heat loss in winter;
- solar gains in summer.
The photograph of this project shows exactly why the building layout matters. A unit placed between two openings does not serve the space in the same way as a unit located at the back of a closed bedroom.
The copper diameter depends on the installed MIDEA35
The model choice also affects the refrigerant lines.
For the versions 9,000 and 12,000 BTU, Midea specifies:
1/4 in. for the liquid line and 3/8 in. for the gas line.
For the 18,000 BTU :
3/8 in. for the liquid line and 5/8 in. for the gas line.
The published maximum lengths are 82 ft. for the 9,000 and 12,000 BTU versions, and 164 ft. for the 18,000 BTU version.
This information becomes essential when replacing an old wall-mounted air conditioner or an old heat pump.
The presence of existing copper lines absolutely does not guarantee their compatibility with the new unit.
A clean installation also means planning the drain carefully
In the photo, no large drain is visible on the face of the wall.
To achieve this result, its route must be planned before installation.
In cooling mode, the moisture removed from the air turns into water on the indoor coil. This water falls into a pan and must then be drained to a suitable location.
Whenever possible, we favor gravity drainage with a continuous slope.
An improperly designed drain can cause:
- indoor leaks;
- water accumulation;
- odors;
- blockages;
- wall damage.
These details are invisible when everything is working properly, but they are essential to the quality of theHVAC installation.
R-454B requires methods suited to A2L systems
The MIDEA35 uses R-454B, an A2L refrigerant. The documentation also refers to an A2L refrigerant leak detection sensor and a dispersion system for the applicable series.
This new generation of equipment requires an installation suited to the refrigerant used.
In particular, we must follow the appropriate procedures for:
- refrigerant connections;
- leak tests;
- evacuation;
- commissioning;
- future service work.
The owner does not have to manage these aspects on a daily basis, but the installer’s expertise becomes particularly important.
Different electrical requirements depending on capacity
The documented MIDEA35 units operate at 208/230 V, single-phase, 60 Hz.
For the 9,000 and 12,000 BTU models, the brochure indicates a minimum allowable ampacity of 16 A, with a maximum protection of 20 A.
For the 18,000 BTU version, the stated minimum ampacity is 24.9 A and the maximum protection is 25 A.
It would therefore be incorrect to automatically conclude that all MIDEA35 units use exactly the same circuit simply because they bear the same series name.
A low noise level for a unit placed near living spaces
A unit located in an indoor traffic area may be relatively close to a living room, bedroom, or office.
The sound level therefore becomes a concrete consideration.
Midea publishes indoor sound levels as low as 19 dB(A) on the 9,000 and 12,000 BTU versions and up to 16 dB(A) on the 18,000 BTU version depending on the operating mode.
The manufacturer also offers a quiet mode.
However, the machine is only one part of the acoustic result. A proper installation should limit vibrations transmitted through the lines and maintain a secure mounting of the unit.
The “Follow Me” function can improve temperature measurement
A wall-mounted unit is generally installed near the ceiling, while occupants are much lower down.
The temperature measured near the unit is therefore not always exactly the same as that felt at human height.
Midea offers the “Follow Me” : the temperature sensor built into the remote control can serve as the reference for regulation when the function is used.
In a space with a staircase, this function can be particularly useful, since warm air naturally tends to rise.
However, the remote control should be placed in a representative location, away from direct sunlight or a local heat source.
Future maintenance: a criterion from the day of installation
The space above a door or between two openings can be very effective for air distribution, but we must also think about the technician who may eventually have to clean the unit.
Midea indicates that the blower wheel of the MIDEA35, 28, and 25 series is removable to facilitate deep cleaning.
Over time, filters are not the only components that accumulate dust.
A thorough maintenance service may include, in particular:
- the heat exchanger;
- the blower wheel;
- the condensate pan;
- the drain;
- interior surfaces.
That is why we want to maintain reasonable access even when the aesthetic goal is to place the unit as discreetly as possible.
LogisVert: What you need to know about a MIDEA35 installed today
The three AHRI references published for the MIDEA35 series are:
- 215471386 — 9,000 BTU;
- 215471387 — 12,000 BTU;
- 215471388 — 18,000 BTU.
For installations carried out as of November 26, 2025, Hydro-Québec requires, among other things, that a heat pump be ENERGY STAR certified. The complete system must be new, and the outdoor unit must have a rated cooling capacity of at least 12,000 BTU/h. Hydro-Québec currently provides assistance of $120 per 1,000 BTU/h at -8°C for an eligible cold-climate heat pump.
This creates an important nuance for the MIDEA35 series: the rated version of 9,000 BTU does not, on its own, meet the current 12,000 BTU/h threshold for rated outdoor capacity set out in this rule. For the 12,000 and 18,000 BTU versions, eligibility and the exact amount must be confirmed based on the installed combination and the current official list.
We are not calculating a specific amount for this project here because the brochure provides performance data at -15°C, while the current subsidy is calculated according to the eligible capacity at -8°C.
For certain multi-unit residential buildings meeting Hydro-Québec’s additional criteria, a bonus that took effect on June 15, 2026 may increase the assistance to $220 per 1,000 BTU/h at -8°C for an eligible ENERGY STAR certified cold-climate wall-mounted heat pump.
Warranty: retain the model and serial numbers
The Midea brochure presents, for the residential sector, a 12-year limited warranty on the compressor, 12 years on parts, and 10 years on labor, subject to the applicable program terms.
We therefore recommend keeping the following with the home’s records:
- the invoice;
- the indoor model number;
- the outdoor model number;
- serial numbers;
- the AHRI reference;
- registration documents;
- the documents related to any rebate application.
Mistakes this installation helps avoid
This project in Salaberry-de-Valleyfield illustrates several common mistakes that we aim to eliminate from the planning stage onward.
Installing the heat pump without considering the doors
A unit placed too close to trim can complicate maintenance or create a visually unbalanced result.
Installing the unit against the ceiling
The unit must retain the clearances specified for its air intake and servicing.
Assuming that a larger capacity is always preferable
Sizing must correspond to the building’s actual needs.
Overlooking the effect of a staircase
Heat naturally moves upward. In a multi-level home, the heat pump’s position relative to the staircase deserves particular analysis.
Reusing copper without verifying its dimensions
The different capacities of MIDEA35 do not all use the same piping.
Promising a rebate based solely on the commercial name
Eligibility depends on the complete model, the AHRI number, and the rules in effect at the time of installation.
A discreet installation in an otherwise highly visible location
This project in Salaberry-de-Valleyfield is a good example of how we work at AirGreen.
The indoor unit is located in a highly visible area of the residence, between two passageways and near a staircase. Yet the result remains understated: the heat pump occupies the upper part of the wall, the trim remains unobstructed, and no bulky ductwork appears on the photographed surface.
Behind this simplicity are the decisions that truly matter: capacity selection, positioning, airflow, mounting, drainage, refrigerant lines, electrical work, evacuation, commissioning, and maintenance access.
The MIDEA MIDEA35 wall-mounted heat pump adds features well suited to four-season use to this installation: heating operation down to -30°C, variable-speed technology, refrigerant R-454B, with efficiency of up to 33.3 SEER2, precise airflow control, and different capacities that make it possible to adapt the equipment to the building.
Our objective in Salaberry-de-Valleyfield keep it simple: make the heat pump’s technical specifications translate into tangible comfort in the home, without compromising space, aesthetics, or ease of future maintenance.
The unit on this job, in figures
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 big day, step by step
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 would it look like 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.
Four mistakes we do not make
Flip each card to see what we do instead.
Your own project, step by step
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.
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.
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).