Installation of a MIDEA35 18,000 BTU wall-mounted heat pump in Brossard: a well-designed mini-split for a residential flat roof
In Brossard, AirGreen installs a MIDEA35 18,000 BTU wall-mounted heat pump on a flat roof with a raised stand, roof protection, and durable HVAC finish.
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.
A rooftop installation demanding precision, stability, and attention to detail
In Brossard, on the South Shore, our AirGreen team recently completed the installation of a MIDEA35 18,000 BTU wall-mounted heat pump, an air conditioning and heating solution designed to offer efficient comfort in a residence where the location of the outdoor unit required a particularly rigorous approach. The photo of this project clearly shows an important detail: the outdoor unit was installed on a flat roof, on a raised structure, with particular attention paid to stability, clearance, roof protection, and future accessibility for HVAC maintenance.
This type of HVAC installation is very common in certain areas of Brossard, Montreal, Longueuil, and residential neighborhoods where ground space is limited, where external aesthetics must be preserved, or when the building's configuration makes a wall-mounted or ground-level installation less appropriate. In this specific case, the objective was simple: to offer the client a reliable, quiet, and efficient system, while respecting the physical constraints of the building and best practices for installation on a roof membrane.
The MIDEA35 18,000 BTU heat pump was chosen for its capacity adapted to the residence's needs, its good balance between performance, comfort, and accessibility, as well as its relevance for owners looking for an efficient solution without falling into an unnecessarily complex configuration. An 18,000 BTU unit can suit several types of spaces: open-plan areas, main floors, large living rooms, spacious condos, residential offices, or living areas where air distribution must be constant and well-controlled.
A MIDEA35 18,000 BTU installed with a structure adapted to Brossard's realities
Why install the outdoor unit on a flat roof?
In this project in Brossard, the rooftop installation offered several concrete advantages. First, it freed up ground space and kept outdoor areas clearer. Second, it avoided imposing the outdoor unit in a visible or cluttered location around the house. Finally, it allowed for a more logical path for refrigerant lines and drainage, according to the chosen interior configuration.
However, a flat roof installation is never improvised. At AirGreen, we always evaluate several elements before confirming this solution:
- the general condition of the roof;
- the type of membrane and the need to protect it;
- the ability to create a stable base without compromising waterproofing;
- the clearance around the outdoor unit;
- exposure to wind, snow, and seasonal accumulations;
- future access for HVAC maintenance or service intervention;
- the cleanest possible path for piping and wiring.
In the photo, we can see that the outdoor unit is placed on a raised metal support. This height is important because it helps keep the unit above snow accumulations, promotes better airflow around the condenser, and facilitates future inspections. Protective blocks are placed under the structure to prevent aggressive contact with the roof. Wooden pieces are also used to stabilize and distribute certain supports, demonstrating the importance of an installation designed for the reality of the terrain rather than a standardized installation without adaptation.
Stability: a critical point for a rooftop heat pump installation
An outdoor heat pump experiences normal vibrations during operation. Even if modern systems, like the MIDEA35 mini split, are designed to operate with reduced noise levels, a poor base can amplify vibrations, create undesirable noises, or accelerate the wear of certain components.
For this installation in Brossard, our team therefore paid particular attention to the rigidity of the support. A well-leveled structure allows the outdoor unit to operate correctly, promotes the planned flow of defrost water, and reduces mechanical stress on refrigerant connections. This point is particularly important in heating, when the unit alternates between operating cycles and defrost cycles during cold periods.
In Montreal, Laval, Longueuil, on the North Shore and the South Shore, climatic variations necessitate a solid installation: rain, frost, heavy snow, winds, and thaw cycles can test a poorly designed base. A durable installation therefore begins well before the final connection: it begins with the correct positioning of the equipment.
An 18,000 BTU capacity well-suited to residential needs
The choice of an 18,000 BTU wall-mounted heat pump is not insignificant. A unit that is too small risks running too long without achieving the desired comfort, while a unit that is too large can lead to short cycles, less controlled humidity in summer, and a less stable sense of comfort. Evaluating the capacity is therefore a crucial step.
In this project, the MIDEA35 18,000 BTU met the client's needs well, as they were looking for a solution capable of providing efficient air conditioning during the hot summer periods on the South Shore, while also offering effective supplementary heating during cooler seasons. The indoor wall-mounted format allows for direct air distribution in the targeted area, with precise temperature control and simple daily use.
At AirGreen, we consider several parameters before recommending a capacity:
- the actual area to be treated;
- ceiling heights;
- the level of insulation;
- the building's orientation;
- sun exposure;
- the number of occupants;
- the presence of large windows;
- natural air circulation between rooms;
- the client's usage habits.
This approach avoids approximate recommendations. It allows us to propose an HVAC installation that meets the actual need, not just a quick estimate based on surface area.
MIDEA35: a practical choice for comfort and energy consumption
The MIDEA35 18,000 BTU model falls into a category sought after by homeowners who want an efficient, reliable, and rational solution. This type of wall-mounted air conditioner with heat pump function can reduce reliance on auxiliary heating systems for a significant part of the year, while significantly improving air conditioning comfort.
One of the advantages of a mini split type system is its modulating operation. Rather than simply turning on and off abruptly, the unit adjusts its capacity according to demand. This modulation helps maintain a more stable temperature, improves acoustic comfort, and optimizes electrical consumption when the installation is properly sized.
For a homeowner in Brossard, this type of solution can be particularly interesting in a house where certain areas become too hot in summer, especially upper floors, sun-exposed rooms, or open spaces where central air conditioning is not present. A well-positioned wall-mounted heat pump provides a direct answer, without major work on walls or ceilings.
The visible details in the photo: what they reveal about the quality of the installation
The provided photo shows an aspect rarely highlighted, yet essential: the technical background of a successful installation. The outdoor unit is installed in a flat roof environment with gravel, parapets, ventilation outlets, and other mechanical elements already present. This type of environment requires true work discipline.
Several points deserve attention:
The unit is clear.
The condenser has sufficient space around it to draw in and expel air. A lack of clearance can reduce efficiency, increase operating pressure, and harm the unit's durability.
The support is raised.
This height protects the unit from snow and water accumulation, while facilitating access to components.
The roof is protected.
The blocks and supports used help prevent direct and concentrated pressure on the membrane. On a flat roof, protecting the building envelope is as important as the machine's performance.
Service access remains possible.
An outdoor unit should never be jammed against an obstacle. Technicians must be able to intervene to clean, check pressures, inspect connections, or perform diagnostics.
These details are not decorative. They directly influence the system's performance, noise, safety, and lifespan.
Mistakes to avoid when installing on a flat roof
Installing a heat pump on a roof may seem simple at first glance, but several mistakes can be costly in the medium term. Here are the most frequent ones we observe during repairs or inspections:
Placing the unit directly on the roof
An outdoor unit should not be placed directly on a membrane. The weight, vibrations, and freeze-thaw cycles can create pressure points and damage the roof.
Neglecting leveling
A poorly leveled appliance can generate vibrations, inadequate defrost water drainage, and premature wear.
Installing too close to a wall, parapet, or ventilation outlet
Lack of clearance impairs heat exchange. A heat pump needs to breathe properly to deliver its full performance.
Forgetting future maintenance
An installation might look clean on day one, but become problematic if no space has been provided for technical access. At AirGreen, we always install with maintenance in mind.
Underestimating snow
In Brossard, as elsewhere on the South Shore, snow and ice can quickly engulf a poorly positioned unit. A raised base is often necessary to ensure more stable operation during winter.
Coordinated work balancing aesthetics, performance, and building constraints
For this wall-mounted air conditioner and MIDEA35 heat pump installation, our team had to combine several objectives. The client wanted an efficient solution, but also a discreet and durable installation. The flat roof was a logical option, provided the correct methods were followed.
The path of the refrigerant lines was designed to minimize losses, reduce visual clutter, and ensure a clean finish. The electrical connection also had to be carefully planned to comply with applicable standards and ensure safe operation. In a complete HVAC installation, every element is linked: indoor location, outdoor location, drainage, electrical supply, pipe length, clearance, noise level, and accessibility.
It is this coordination that makes the difference between a simply functional installation and a truly professional one.
Customer experience: more stable comfort without compromising outdoor space
After commissioning, the client quickly noticed improved comfort in the targeted area. The mini split operates to quickly reach the desired temperature, then maintain it consistently. In summer, this means fewer unpleasant variations and better humidity management. In mid-season, the heat pump's heating function allows for tempering the space without necessarily relying on the main heating system.
Another advantage appreciated by the client: the outdoor unit does not monopolize the yard, terrace, or a side passage. In dense residential areas of Brossard, this space saving can be a real benefit. The rooftop installation, when properly done, preserves the outdoor layout while ensuring system performance.
AirGreen expertise built on real installations in Greater Montreal
At AirGreen, we carry out installations of wall-mounted heat pumps, wall-mounted air conditioners, multi-zone systems, and HVAC solutions throughout Greater Montreal: Montreal, Laval, Longueuil, the North Shore, and the South Shore. Each sector has its peculiarities. Houses in Brossard do not always have the same constraints as Montreal plexes, Laval condos, or more spaced-out properties on the North Shore.
This field experience allows us to adapt our recommendations. We know, for example, that a flat roof installation requires more than just a simple support. It requires thought about the roofing, prevailing winds, access, snow, vibrations, and the overall longevity. We also know that a well-chosen system must be accompanied by rigorous installation to deliver the expected savings and comfort.
In this project, the MIDEA35 18,000 BTU represented an excellent choice to meet the client's demand, but it is the quality of the installation that allows the appliance to perform at its best.
Subsidies and eligibility: a point to check before installation
Many homeowners considering the installation of a heat pump also want to understand available subsidies. Programs can vary based on eligibility criteria, updated model lists, performance requirements, and administrative conditions. For a wall-mounted heat pump like the MIDEA35 18,000 BTU, it's important to check the latest information before confirming a purchase, especially when a program like Hydro-Québec's LogisVert is being considered.
At AirGreen, we help our clients better understand the usual steps: paid invoice, model information, proof of installation, and submission of required documents when the model is eligible. This assistance is particularly useful for avoiding file errors, incomplete information, or unrealistic expectations regarding processing times.
Practical tips for Brossard homeowners considering a similar installation
For homeowners in Brossard and the South Shore who are thinking of installing a wall-mounted heat pump on a flat roof, several tips can help avoid future problems.
First, carefully choose the outdoor location. The best spot isn't always the closest to the indoor unit. Air circulation, roof structure, obstacles, perceived noise, and service access must be considered.
Next, plan for an appropriate base. A raised and stable structure is often preferable, especially in our climate. The roof must be protected, and the installation must not compromise the building's watertightness.
It's also essential to choose the right capacity. An 18,000 BTU unit can be excellent in many situations, but it must match the reality of the space. A technical visit allows for a much more precise validation of this choice.
Finally, maintenance should not be neglected. Even a good heat pump needs regular filter cleaning, periodic inspection, and sufficient clearance around the outdoor unit. Good maintenance extends the system's lifespan, maintains efficiency, and reduces the risk of breakdowns.
A MIDEA35 installation that reflects our work method
This installation of a MIDEA35 18,000 BTU wall-mounted heat pump in Brossard clearly illustrates our approach at AirGreen: choosing suitable equipment, planning every detail, respecting the building, protecting the roof, and ensuring a durable finish. The result is a clean, stable, and functional installation, designed for the client's daily comfort as much as for long-term performance.
In the HVAC field, a good machine is not enough. The quality of the installation directly influences performance, noise level, reliability, energy consumption, and owner satisfaction. That's why we place so much importance on details that aren't always visible at first glance: leveling, clearances, supports, pipe routing, roof protection, and service access.
For homeowners in Brossard, Montreal, Laval, Longueuil, the North Shore, and the South Shore, this project demonstrates that a flat roof installation can be an excellent solution when designed and executed by an experienced team.
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).