Installation of a MIDEA MIDEA35 wall-mounted heat pump in the Dundee neighborhood: a flat-roof installation built to last
AirGreen installation of a MIDEA35 wall-mounted heat pump in Dundee: outdoor unit elevated on a flat roof, sturdy metal support, and a configuration adapted to Quebec winters.
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.
A MIDEA35 installed on an elevated structure to protect the unit and preserve the roof
This installation of a MIDEA MIDEA35 wall-mounted heat pump in the Dundee area has a very different configuration from a conventional residential ground-level installation. Here, the outdoor unit had to be installed directly on a flat roof covered with gravel, amid several mechanical systems, vents, and roof outlets.
In this type of project, choosing the equipment represents only part of the work. How the outdoor unit is supported, elevated, positioned, and connected becomes equally important.
In the project photograph, we can see the outdoor unit Midea installed on a sturdy metal structure. This structure is itself supported by wooden elements arranged on the roof to distribute the load and create a stable base. The heat pump is therefore not placed directly on the gravel or the roof membrane.
This solution meets several important objectives: keeping the unit at an appropriate height, protecting the roof, facilitating drainage around the heat pump, and maintaining sufficiently clear access for service work.HVAC maintenance future.
The series MIDEA35 is presented by Midea as its premium wall-mounted range. It operates with R-454B, is identified Cold Climate V6.1 and can operate in heating mode down to -30°C. Depending on the selected capacity, its efficiency can reach 33.3 SEER2 and 22.0 HSPF2.
Why install a wall-mounted heat pump on a roof?
When space around a building is limited or when the existing layout makes a ground-level installation impractical, the roof can become an excellent location for the outdoor unit of a wall-mounted heat pump.
In the Dundee area, this project required us to consider several factors before permanently securing the equipment:
- the structural capacity of the selected area;
- protection of the roofing membrane;
- air circulation around the unit;
- the proximity of other equipment;
- future access for maintenance and servicing;
- the height of the support;
- the routing of the refrigerant and electrical lines;
- winter conditions.
An outdoor unit should never simply be placed wherever seems most convenient at first glance. On a flat roof, the presence of snow, ice, and meltwater must be taken into consideration when designing the support.
Midea documentation specifically emphasizes that its side-discharge outdoor units offer a relatively compact design and can be installed on different types of supports.
A metal structure that keeps the unit away from the roof surface
The most distinctive element of this HVAC installation in Dundee is undoubtedly the elevated support.
In the photo, four metal legs support a horizontal frame on which the Midea unit rests. The feet are attached to two long wooden beams.
This configuration allows us to keep clear space beneath the unit.
This clearance is particularly useful for a heat pump that operates during the winter. During the heating cycle, a heat pump must periodically perform defrost cycles. The resulting water must be able to drain away without immediately turning the base of the unit into a block of ice.
The elevation also helps prevent snow accumulation around the machine from blocking the air intake and discharge areas too quickly.
A flat roof requires a different approach from a ground installation
Installing a heat pump in Dundee on a roof also means that we must consider the roof itself.
The membrane must not be unnecessarily perforated or subjected to concentrated loads without preparation. The support must remain stable while preventing the installation from creating problematic pressure points.
The wooden beams visible beneath the metal structure serve here to provide a stable longitudinal base and better distribute the load across the surface.
This method also creates separation between the metal structure and the gravel layer.
Every roof is different, however. We must therefore examine the type of construction, the condition of the roof, and the building’s constraints before choosing the support solution.
Clearance in front of the outdoor fan is essential
In the image, the large circular grille of the Midea unit faces a largely unobstructed area.
This detail is fundamental.
A side-discharge heat pump must move a large volume of air through its heat exchanger. If obstacles are too close to the fan, the discharged hot or cold air may recirculate into the unit, which can affect its efficiency.
On a roof where several pieces of equipment are grouped together, we must avoid as much as possible:
- to place two units facing each other at a very short distance;
- to position the heat pump too close to a wall;
- to block air intake;
- to install the unit in a space where snow could accumulate excessively;
- to make the service panel inaccessible.
The visible positioning on this project Dundee leaves a significant area in front of the fan grille, which facilitates air discharge.
MIDEA35: three different capacities within one range
The MIDEA35 series is available in several capacities. According to the manufacturer’s documentation, three main configurations are offered:
| Cooling capacity | Indoor model | Outdoor model | AHRI reference |
|---|---|---|---|
| 9,000 BTU/h | MSESU-H09B-2A | MO1SS-H09B-2A | 215471386 |
| 12,000 BTU/h | MSESU-H12B-2A | MO1SS-H12B-2A | 215471387 |
| 18,000 BTU/h | MSESU-H18B-2A | MO1SS-H18B-2A | 215471388 |
Midea indicates nominal heating capacities of 12,000, 12,000, and 20,000 BTU/h.
Since the rating plate is not sufficiently legible in the photograph of this installation, we cannot reliably confirm the exact installed capacity. We therefore prefer to present the different MIDEA35 configurations rather than arbitrarily assigning a BTU rating to the project.
At AirGreen, this precision matters: a technical article must reflect what we can actually confirm about an installation.
Up to 33.3 SEER2 depending on capacity
The MIDEA35 range stands out in particular for its high seasonal efficiency.
The published values are:
- 33.3 SEER2 for the 9,000 BTU model;
- 29.4 SEER2 for the 12,000 BTU model;
- 25.6 SEER2 for the 18,000 BTU model.
For heating, the published HSPF2 IV values are respectively 22.0, 14.5, and 16.2.
These data also demonstrate a reality that is often misunderstood: two heat pumps bearing the same series name may deliver different performance depending on their capacity.
That is why we always verify the model number and the exact AHRI combination.
Variable-speed technology adapted to the building’s actual needs
Midea uses variable-speed technology that allows the compressor to modulate its operation according to the demand for heating or cooling.
Instead of operating only at full capacity and then stopping, the system can adjust its output. According to Midea documentation, this modulation helps reduce temperature fluctuations and maintain more consistent comfort.
In everyday use, this can result in smoother operation.
When the indoor temperature approaches the setpoint, the heat pump can reduce its capacity rather than multiply on-off cycles.
A rooftop installation requiring as much precision as choosing the MIDEA35
Heating down to -30°C: an important factor for Dundee
Midea annonce une plage de fonctionnement en chauffage jusqu’à -30°C Midea states a heating operating range down to for all three configurations in the MIDEA35 series. The operating range in cooling is specified up to.
50 °C
For a Quebec installation, low-temperature performance is obviously a major criterion.
However, it is important to understand that a heat pump that “operates down to -30 °C” does not necessarily provide the same capacity at all temperatures. The documentation provides, for example, the following rated capacities at :
- for the 9,000 BTU model; -15 °C
- for the 9,000 BTU model; 13,500 BTU/h
- for the 12,000 BTU model; 22,600 BTU/h
for the 18,000 BTU model.
To determine whether a heat pump can meet a large portion of a space’s heating needs, this data is much more relevant than the minimum advertised temperature alone.
The piping must correspond exactly to the selected model
In a rooftop installation, planning the refrigerant line route is particularly important because the distance between the indoor and outdoor units may be greater than in a standard installation. For the 9,000 and 12,000 BTU MIDEA35 models, Midea specifies 1/4 in. and 3/8 in. lines..
The 18,000 BTU configuration uses 3/8 in. and 5/8 in. lines. 3/8 in. and 5/8 in..
The specified maximum lengths also differ:
- up to 82 ft for the 9,000 and 12,000 BTU versions;
- up to 164 ft for the 18,000 BTU version.
When a unit must be installed on the roof, these limits are checked before work begins.
Do not overlook the wiring and electrical protection
All three MIDEA35 models operate on 208/230 V, single-phase, 60 Hz.
However, the outdoor unit requires different electrical specifications depending on its capacity.
Midea specifies:
- a minimum allowable current of 16 A and a maximum fuse of 20 A for the 9,000 and 12,000 BTU models;
- a minimum allowable current of 24.9 A and maximum protection of 25 A for the 18,000 BTU model.
A heat pump installation should therefore never be confirmed without first checking the available electrical supply.
Noise and vibrations are particularly important on a roof
When an outdoor unit is installed on a roof, we pay particular attention to vibrations.
A vibration that would barely be noticeable on a support installed on the ground can sometimes be transmitted more readily through a building’s structure when the unit is installed at height.
That is why the support, stability of the assembly, and quality of the mounting are essential considerations.
For MIDEA35 outdoor units, the documentation indicates a maximum sound level of 57 dB(A) for the 9,000 and 12,000 BTU versions and 61.5 dB(A) for the 18,000 BTU model.
These figures do not replace proper mechanical installation. A heat pump that is improperly levelled or installed on an unstable support may produce more vibrations, even if the unit itself is designed to operate quietly.
The elevated position also facilitates certain maintenance work.
The structure visible on this Dundee project offers another advantage: the unit remains more accessible.
A technician must be able to reach the service panels, inspect the connections, clean the heat exchanger, and perform the necessary checks without having to work against the roof membrane.
Maintenance is just as important on the indoor side.
For the MIDEA35, 28, and 25 series, Midea indicates that the indoor fan wheel can be removed to facilitate deep cleaning.
Over time, dust can accumulate on:
- the filters;
- the heat exchanger;
- the blower wheel;
- the louvers;
- the drain pan.
A HVAC maintenance periodic maintenance therefore helps preserve airflow and the cleanliness of the unit.
Several comfort functions integrated into the MIDEA35 series
Beyond its heating and cooling performance, the MIDEA35 offers several control functions.
The brochure mentions, among other things:
- ECO mode;
- Turbo mode;
- night mode;
- timer;
- silent mode;
- the function Follow Me;
- 8°C heating;
- Wi-Fi control;
- fan setting;
- horizontal and vertical swing;
- humidity control;
- the smart sensor;
- automatic cleaning.
The Follow Me function uses, among other things, the temperature sensor built into the remote control to measure the temperature closer to the occupant.
Midea also indicates that the indoor fan can be set to different levels, allowing the airflow to be adjusted more precisely.
Mistakes to avoid when installing a heat pump on a flat roof
Our installation in the Dundee neighbourhood highlights several mistakes that are best avoided.
Placing the unit directly on the roof
A heat pump placed directly on gravel may be too low relative to snow, drainage water, and winter accumulation.
Using a support that is too light
The support must withstand the weight of the unit, vibrations, and outdoor conditions.
Depending on its capacity, the MIDEA35 outdoor unit weighs approximately 99.65 lb for the 9,000 and 12,000 BTU versions and 130.29 lb for the 18,000 BTU model.
Blocking the fan
A side-discharge unit must have sufficient space in front of its grille.
Forgetting about future access
A beautiful installation is not necessarily a good installation if the technician has to dismantle other equipment to reach the service panel a few years later.
Choosing BTUs solely according to the available space
Capacity must be selected according to heating requirements, not simply the physical size of the outdoor unit.
Rebates: always verify the exact AHRI number
The three MIDEA35 combinations listed in the documentation have the AHRI reference numbers 215471386, 215471387, and 215471388 and are listed Cold Climate V6.1.
To determine eligibility for financial assistance, we always recommend checking the exact combination installed at the time of the project.
Since programs and their criteria may change, simply mentioning “MIDEA35” is not enough to automatically guarantee a particular rebate.
A particularly comprehensive residential warranty according to the Midea brochure
The documentation provided by Midea presents, for the residential sector, a 12-year limited warranty on the compressor, 12 years on parts, and 10 years on labor, according to the applicable conditions.
As always, the registration terms, exclusions, and manufacturer requirements must be followed to maintain the applicable coverage.
This Dundee job illustrates our approach at AirGreen
This MIDEA MIDEA35 wall-mounted heat pump installation in the Dundee neighborhood is a good example of a project where much of the expertise lies beneath the unit rather than in the equipment itself.
The photograph shows a properly elevated machine installed on a metal structure, with a base designed to distribute the load across a gravel-covered flat roof. The fan has ample clearance, and the positioning preserves access for servicing.
These are precisely the details we assess on our heat pump, air conditioning, and heating.
At AirGreen, our work does not simply consist of bringing a heat pump to the job site and connecting it. We must consider the entire building: outdoor unit location, structure, piping, electrical system, drainage, airflow, noise, vibrations, and future maintenance.
The MIDEA35 provides technical features suited to Quebec’s climate: heating down to -30°C, variable-speed technology, refrigerant R-454B, certification Cold Climate V6.1 and efficiency of up to 33.3 SEER2.
But on this project for Dundee, the feature that particularly stands out is the quality of the rooftop integration. A high-performance heat pump deserves a support system and installation designed with the same rigor as the equipment itself.
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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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?
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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).