Project

Installation of a MIDEA28 triple-zone wall-mounted heat pump in Sainte-Marthe-sur-le-Lac: 3-zone mini-split designed for year-round residential comfort

AirGreen installs a MIDEA28 triple-zone wall-mounted heat pump in Sainte-Marthe-sur-le-Lac: 3-zone mini-split, rooftop unit, precise comfort, and durable HVAC installation.

By AirGreen Climatisation & Chauffage Admin16 min read
Installation of a MIDEA28 triple-zone wall-mounted heat pump in Sainte-Marthe-sur-le-Lac: 3-zone mini-split designed for year-round residential comfort
Installation of a MIDEA28 triple-zone wall-mounted heat pump in Sainte-Marthe-sur-le-Lac: 3-zone mini-split designed for year-round residential comfort
–chapters in this story
16 minreading time
–type of installation
2026year published
The tour

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.

Generic diagram: wall-mounted heat pump, indoor and outdoor units

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.

  1. 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.

  2. The refrigerant lines, the communication cable and the drain go through the wall in a single opening, sealed against water, cold air and insects.

  3. Two insulated copper pipes connect the two units. Outside, a line cover can protect them from sun, knocks and weather.

  4. A shut-off switch near the outdoor unit isolates it safely for service. It must stay accessible at all times.

  5. The compressor and the fan. In heating mode it captures heat from the outdoor air, even in winter, and moves it inside.

  6. On the ground or on the wall, it keeps the unit above accumulated snow. The unit stays clear and defrost water can drain away.

  7. The fan needs to blow freely. Storage, a fence or a wall too close, and efficiency drops while noise goes up.

The job

A Rooftop HVAC Installation, Designed to Maximize Space, Performance, and Quiet Operation

In Sainte-Marthe-sur-le-Lac, our AirGreen team recently completed a particularly interesting HVAC installation: a MIDEA28 triple-zone wall-mounted heat pump, also known as a 3-zone mini-split air conditioner, with the outdoor unit installed on a flat roof in the middle of winter. This type of project requires rigorous planning, excellent mastery of mechanical constraints, and particular attention to the durability of the installation, especially when the outdoor unit must operate in the demanding climatic conditions of the Montreal, Laval, Longueuil, North Shore, and South Shore regions.

The photo of this installation clearly shows the outdoor unit positioned on a raised base, constructed with robust wooden supports and an adapted metal structure. This detail is essential: in winter, a heat pump installed too close to the roof surface risks being exposed to snow accumulation, ice, freeze-thaw cycles, and poor air circulation around the coil. In this specific case, our objective was simple: to ensure a stable, clear, accessible, and durable installation, while respecting the building's constraints.

This MIDEA28 triple-zone heat pump was chosen to allow three distinct spaces to benefit from independent temperature control. This is one of the great advantages of 3-zone mini-split systems: each room or sector can be heated or cooled according to its actual needs, without forcing the entire house to operate at the same intensity. For a residence in Sainte-Marthe-sur-le-Lac, where temperature variations between rooms can be significant depending on sun exposure, insulation, the presence of large windows, or daily use of spaces, this solution provides a highly appreciated level of comfort.

Technical Challenges of a Triple-Zone Heat Pump Installed on a Flat Roof

Installing a triple-zone wall-mounted heat pump is never limited to placing an outdoor unit and connecting three wall units. Each project requires an analysis of the building, the path of the refrigerant lines, the electrical supply, condensate drainage, and the ideal location for each component. In this project in Sainte-Marthe-sur-le-Lac, the roof added several significant constraints.

A Raised Outdoor Unit to Better Withstand Quebec Winters

The outdoor unit visible in the photo is installed on a raised base, with good ground clearance. This approach is particularly important for a rooftop HVAC installation. During snowy periods, a heat pump must maintain sufficient clearance around its outdoor coil to ensure efficient heat exchange. If snow blocks airflow, efficiency decreases, defrost cycles may become more frequent, and the unit may work harder than necessary.

We therefore paid particular attention to several points:

  • the height of the unit relative to the roof surface;
  • the stability of the base despite wind, frost, and vibrations;
  • clearance in front of the ventilation grille;
  • accessibility for future HVAC maintenance;
  • protection of refrigerant and electrical lines;
  • clean integration with the existing roof environment.

The wooden base and metal supports allowed for proper load distribution, kept the unit well-aligned, and reduced risks associated with water, snow, or ice accumulation around the unit. This type of detail may seem secondary, but it plays a direct role in the machine's longevity.

Well-Protected Refrigerant Lines

The photo also shows the insulated refrigerant lines, exiting the outdoor unit and protected against external conditions. In a triple-zone heat pump installation, these lines are crucial: they transport refrigerant between the outdoor unit and the indoor units. Their insulation must be continuous, clean, and resistant to reduce thermal losses and prevent condensation or premature deterioration.

On a flat roof, these lines are more exposed to UV rays, wind, humidity, temperature variations, and potential interventions by other trades. Our team therefore paid special attention to the mechanical and thermal protection of the route, with a focus on a clean and durable finish.

Precise Coordination for Three Indoor Zones

A 3-zone mini-split system like the MIDEA28 requires good coordination between indoor needs and the outdoor unit's capacity. Each wall-mounted head must be positioned to ensure good air diffusion, without blowing directly on occupants, without conflicting with furniture, and without creating dead zones. In Sainte-Marthe-sur-le-Lac, this consideration was essential, as the client wanted to improve comfort in several spaces without multiplying outdoor units.

A single, well-sized outdoor unit can serve three zones, which offers several concrete advantages:

  • less outdoor clutter;
  • a cleaner appearance on the building;
  • centralized system management;
  • interesting energy efficiency;
  • personalized comfort in each room;
  • a solution adapted to homes where needs vary from one floor or sector to another.

Why the MIDEA28 is an Excellent Choice for a Triple-Zone Installation

The MIDEA28 triple-zone wall-mounted heat pump is often chosen for residential projects where the client seeks a balance between performance, price, versatility, and comfort. In the Quebec market, this type of system meets a very clear demand: reducing reliance on traditional electric heating, improving summer comfort, and avoiding the installation of multiple outdoor units when several rooms need to be treated.

A Solution Adapted for Both Heating and Air Conditioning

The MIDEA28 functions as a heat pump in winter and an air conditioner in summer. In heating mode, it transfers heat from the outside air indoors, even when the temperature drops. In air conditioning mode, it extracts indoor heat to cool rooms. For homeowners in Sainte-Marthe-sur-le-Lac, this dual function is particularly useful: winters are cold, summers can be humid, and transitional seasons often require gentle heating or occasional air conditioning.

A well-installed wall-mounted heat pump often provides more uniform comfort than an auxiliary system used only in one room. With three zones, the house gains flexibility. A bedroom can be kept cooler, a living room more comfortable in the evening, and a home office can be heated or cooled only when in use.

Better Control of Energy Consumption

One of the great advantages of a 3-zone mini-split heat pump is the ability to heat or cool based on the actual use of rooms. Instead of overheating the entire house or cooling unoccupied spaces, the client can adjust each zone independently. This approach is particularly relevant in modern homes, condos, townhouses, and buildings where certain rooms are more exposed to the sun or harder to temper.

At AirGreen, we often emphasize this point during our evaluations: the right system is not just one with high capacity, but one that truly matches the building's configuration and the occupants' lifestyle. A unit that is too small will run continuously without achieving the desired comfort. A unit that is too large can create short cycling, negatively impact dehumidification, and reduce efficiency. In the case of this installation in Sainte-Marthe-sur-le-Lac, the choice of the MIDEA28 met a specific need for distribution across three zones.

A More Discreet Installation Than a System with Multiple Condensers

When three rooms need to be air-conditioned or heated, some owners consider installing three independent single systems. This solution can work in some cases, but it multiplies the outdoor units, supports, electrical supplies, and penetrations. In a residential environment, especially when the outdoor unit is installed on a roof, a triple-zone configuration is often more elegant and practical.

Here, the client benefits from a single, well-positioned outdoor unit, with three coordinated indoor units. The result is visually cleaner, easier to maintain, and better suited to a roof where space must be used intelligently.

Key Steps of the AirGreen Installation in Sainte-Marthe-sur-le-Lac

Every AirGreen project begins with a detailed assessment. Even if two houses seem similar, the actual conditions can be very different: building orientation, insulation, ceiling height, roof access, electrical panel location, wall structure, presence of obstacles, co-ownership or neighborhood rules, and client preferences.

Needs Analysis and Zone Selection

Before installation, our team validated the zones to be treated, the required capacity, and the most logical path between the indoor units and the outdoor unit. For a triple-zone system, this step is crucial. Piping distances, elevation changes, maximum allowable lengths, and ease of access for maintenance must be considered before starting work.

We also evaluated the location of the outdoor unit on the roof to preserve:

  • good airflow;
  • safe access for technicians;
  • protection against snow accumulation;
  • a reasonable distance from edges;
  • clean integration with existing mechanical elements.

Base Installation and Outdoor Unit Mounting

The base visible in the photo plays an essential role in the final quality of the installation. It not only supports the unit; it helps limit vibrations, protect the unit from stagnant moisture, maintain necessary clearance, and facilitate future interventions.

A rooftop HVAC installation must be carried out with care, as improper fastening can lead to noise, undesirable movements, or premature wear. Our team therefore installed the outdoor unit stably, straight, and accessibly, taking into account the immediate environment.

Refrigerant and Electrical Connections, and Performance Tests

Once the outdoor unit was in place, refrigerant and electrical connections were made according to industry best practices. Lines were insulated and protected, then the system was checked before commissioning. This step includes checking connections, proper circuit evacuation, pressurization when necessary, validating communication between indoor and outdoor units, and functional tests for heating and cooling.

For a triple-zone heat pump, it is essential to verify that each zone responds correctly to commands, that the indoor units communicate well with the outdoor unit, and that the system's behavior is stable. A connection or identification error between zones can cause performance problems. That's why our technicians take the time to validate every detail before considering the project complete.

Mistakes to Avoid When Installing a 3-Zone Mini-Split

A triple-zone wall-mounted heat pump can offer excellent performance, but only if it is well-chosen and well-installed. Several common mistakes can reduce performance or create problems in the medium term.

Installing the Outdoor Unit Too Low

In a region like Sainte-Marthe-sur-le-Lac, Laval, or the North Shore, snow must be taken seriously. An outdoor unit installed too close to the ground or a flat roof can be partially blocked by snow. This impairs airflow, increases defrost frequency, and can reduce comfort during very cold periods.

Neglecting Accessibility for Maintenance

A system that works well today must also be easy to inspect tomorrow. HVAC maintenance for a heat pump includes cleaning filters, inspecting units, checking drains, insulation condition, coil cleanliness, and general operational control. On a roof, realistic access for technicians must be planned.

Choosing a Capacity Without Considering the Actual House

The choice of a MIDEA28 system or any other model must be based on the building's actual needs. The number of rooms is not enough. Insulation, windows, orientation, ceiling height, type of occupancy, and comfort expectations must also be considered. At AirGreen, we don't recommend a unit just because it's popular; we recommend it when it fits the project.

Underestimating the Importance of Exterior Finishing

Piping, supports, penetrations, and exterior protections influence not only the appearance of the installation but also its durability. A neglected finish can expose refrigerant lines to damage, create infiltration, or complicate future maintenance. In this project, the protection of connections and rooftop positioning were among the priorities.

Customer Experience: Better Distributed Comfort and a Clean Installation

After commissioning, the client was able to enjoy a more flexible system, capable of controlling three distinct zones from a single outdoor unit. This type of result is often highly appreciated, especially in homes where certain rooms become too hot in summer or too cold in winter.

The difference is particularly noticeable in spaces where comfort was previously difficult to maintain. An upstairs bedroom can finally remain comfortable during summer nights. A sun-exposed living room can be cooled without unnecessarily chilling the rest of the house. An office or family room can be heated only when in use.

At AirGreen, we often see this type of transformation in projects completed in Montreal, Laval, Longueuil, on the North Shore and the South Shore. A well-planned system not only improves daily comfort but also the overall perception of the home. The client no longer needs to compensate with portable appliances, fans, or excessive use of electric baseboard heaters.

Subsidies, Energy Efficiency, and AirGreen Support

Depending on the exact model, the installed configuration, and the criteria in effect at the time of the work, certain heat pumps may be eligible for subsidy programs, especially when the appliance meets applicable energy efficiency requirements. For clients, this aspect can significantly influence the net cost of the project.

At AirGreen, we support our clients in understanding the available criteria, required documents, and general steps to follow. It is important to keep invoices, technical information about the installed system, and necessary proofs for any subsidy application. Programs may evolve, and eligibility always depends on the model, capacity, certification, and official conditions in force.

Beyond subsidies, a well-chosen wall-mounted heat pump can help reduce heating and cooling costs, especially when it replaces or complements less efficient systems. In a triple-zone installation, potential savings also depend on usage: the more intelligently the client adjusts the zones according to their habits, the more efficiently the system can operate.

Why entrust a triple-zone installation to AirGreen

An HVAC installation like this requires experience, especially when it combines several technical elements: an outdoor unit on the roof, three indoor zones, line protection, winter constraints, multiple refrigeration connections, and detailed commissioning. Our AirGreen team regularly works on residential and multi-zone projects in Montreal, Laval, Longueuil, on the North Shore and the South Shore, with an approach focused on durability and precision.

Our clients choose us for several concrete reasons:

  • a clear assessment before work;
  • recommendations adapted to the building;
  • a clean installation in accordance with best practices;
  • particular attention to invisible details;
  • solid experience with wall-mounted, multi-zone, and mini-split systems;
  • post-installation support;
  • ability to manage complex projects, including on rooftops or in co-ownerships.

In this project in Sainte-Marthe-sur-le-Lac, the photo clearly shows one of the aspects that distinguishes a professional installation: the outdoor unit is not simply placed on the roof. It is elevated, aligned, accessible, and carefully connected. It is this level of detail that makes the difference between an installation that only works initially and one designed to last.

A well-installed MIDEA28 triple-zone heat pump for lasting comfort in Sainte-Marthe-sur-le-Lac

This achievement in Sainte-Marthe-sur-le-Lac perfectly illustrates the benefit of a MIDEA28 triple-zone wall-mounted heat pump for owners who want to improve their comfort without multiplying outdoor units. The system allows heating and cooling three distinct zones, while maintaining a compact and well-organized outdoor installation.

The rooftop location, visible winter conditions, elevated base, and connection protection demonstrate the importance of serious planning. In the field of HVAC, the quality of an installation is not only measured by its final appearance; it is also measured by the stability of the system, the logic of the pipe routing, ease of maintenance, winter performance, and customer satisfaction after several seasons of use.

For AirGreen, every project is an opportunity to offer a solution truly adapted to the building. Whether it's a house in Sainte-Marthe-sur-le-Lac, a condo in Montreal, a semi-detached house in Laval, a residence in Longueuil, a property on the North Shore or a project on the South Shore, our priority remains the same: to install heat pump, wall-mounted air conditioner, and mini-split systems that offer reliable comfort, a meticulous finish, and performance that meets expectations.

The steps

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.

Step 1 of 9The on-site estimate

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.

  1. 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.
  2. The quoteModel, capacity and price, in writing. We also check whether the model qualifies for assistance programs.
  3. Getting readyFloors and furniture protected, wall plate position marked level, wall opening located.
  4. The wall openingA single opening, with the slope the drain needs to flow outside.
  5. The outdoor unitSet on a stand raised above the snow, with the clearances the manufacturer requires.
  6. Lines, cable and drainConnected, insulated and protected. The opening is then sealed against water, cold air and insects.
  7. The electrical workA dedicated circuit and an accessible disconnect near the outdoor unit.
  8. Tests and start-upLeak test, vacuum, then start-up and a check of heating and cooling.
  9. The walkthroughRemote, modes, filters: we show you the essentials before we leave.
Your numbers

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.

Size checkYour baseboards, in BTU/h
–BTU/h of installed electric heat

    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.

    Mistakes avoided

    Four mistakes we do not make

    Flip each card to see what we do instead.

    Going further

    Your own project, step by step

    Through the seasons

    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.
    At your place

    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.

    0 / 6 checked
    True or false

    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.

    2. You pick the capacity with a simple square-footage rule.

    3. A multi-zone connects several indoor heads to a single condenser.

    4. The disconnect can sit behind the patio furniture.

    Frequently asked questions

    What people ask us about this kind of work

    12 questions
    Does a wall-mounted heat pump heat in winter?
    Yes, it heats and cools. Its capacity drops in very cold weather; the operating range depends on the model and is listed on its spec sheet.
    Wall-mounted or multi-zone: how do I choose?
    One wall head and one condenser outside: the direct solution for a room or an open area. For two to five rooms, a multi-zone puts one head in each room on a single condenser.
    Where does the outdoor unit go?
    Where it stays above the snow, clear and accessible, away from walkways. We decide it with you during the estimate.
    Are there grants?
    Depending on the model and your situation, assistance programs may apply, including Hydro-Québec's LogisVert. AirGreen checks the model number before quoting an amount. See the grants.
    Do I need a permit?
    Rules vary from city to city: location, distances, noise. See permits and by-laws, and we check for your address.
    How cold can it heat?
    It depends on the model. According to Hydro-Québec, newer models work down to a temperature between −15 °C and −25 °C, and some cold-climate models are certified lower. The minimum temperature is on each unit's spec sheet.
    How much can I save?
    Hydro-Québec says a heat pump can be up to three times more efficient than baseboards for heating in the colder months. The result depends on the house, the climate and how it is used.
    How is the LogisVert assistance calculated?
    For ENERGY STAR cold-climate certified heat pumps, Hydro-Québec lists assistance of $120 per 1,000 BTU/h of heating capacity at −8 °C. AirGreen checks the exact model before quoting an amount; only Hydro-Québec confirms the assistance granted. See the grants.
    Is it noisy?
    The sound level depends on the model and is listed in decibels on each unit's spec sheet. Location matters too: when possible, we avoid putting the outdoor unit under a bedroom window.
    The outdoor unit is covered in ice: is that normal?
    Some frost is: the unit runs defrost cycles. Never hit the ice. If the unit stays iced up or stops heating, call us.
    Does AirGreen hold the required licences?
    Yes. AirGreen holds RBQ licence 5645-9605-01, subclasses 15.8 Ventilation, 15.10 Refrigeration and 16 Electricity.
    Is the estimate free?
    Yes. The on-site estimate is free and the quote follows within 24 hours. Book my free estimate.

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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).

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