Installation of a MIDEA MIDEA 28 three-zone heat pump in Carignan

In Carignan, a triple-zone installation where the precise positioning of each indoor unit matters just as much as the heat pump's performance

On this residential project completed in Carignan, on Montreal's South Shore, we installed a MIDEA MIDEA 28 triple-zone heat pump to provide more precise control of heating and cooling in several areas of the property. This type of project may seem simple when summarized as “one outdoor unit and three wall-mounted heads,” but the actual installation requires much more thought: each indoor unit must be positioned according to the room's layout, available clearances, air circulation, refrigerant line routing, and the finish desired by the homeowner.

The photo of this installation shows one of those details that makes all the difference. TheMIDEA wall-mounted unit was installed very high on the wall, near the ceiling, in an area where the available space was limited by the proximity of a door opening. We worked with this architectural constraint rather than choosing an easier but less logical location for the room's comfort.

The lines exiting the unit were grouped into a white line-set cover, with a short, orderly route toward the right side. This finish protects the components while maintaining a clean appearance in a room where the system necessarily remains visible.

This is precisely the kind of situation where a professional HVAC installation stands out: choosing the system is only part of the work. Its integration into the building also determines the quality of the result.

A triple-zone heat pump: three spaces, but only one outdoor unit

The Midea multi-zone system is based on an architecture particularly well suited to homes with multiple bedrooms, floors, or living areas: a single outdoor unit can power multiple indoor units, each of which is controlled individually. Midea documentation specifies that each indoor unit can be adjusted and programmed separately according to the desired temperature.

In the case of this installation in Carignanthis architecture allows us to create three comfort zones without having to add multiple outdoor units around the house.

Specifically, this allows the homeowner to:

• set a different temperature in each zone;
• reduce demand in a room that is temporarily unused;
• cool a room that accumulates more heat more intensively;
• heat a bedroom independently of a living area;
• keep a single outdoor unit for the three zones;
• limit clutter around the property.

Midea also presents individual control as one of the essential advantages of its multi-zone design: users can heat or cool the spaces they use rather than automatically treating the entire house in the same way.

Why the position of this wall-mounted unit is particularly advantageous

In the photo of the Carignan project, the indoor unit is installed very close to the ceiling. On the right, we had relatively little space before the door frame.

A location like this must be assessed before the first hole is drilled.

We had to maintain good air distribution

A wall-mounted heat pump projects air into the room through its lower louver. It must therefore be positioned to promote efficient distribution rather than sending air directly into an obstacle.

Installing the unit high helps conditioned or heated air distribute throughout the room, but height alone is not enough: we must also consider the opposite wall, furniture, doors, and how the occupants use the space.

In this room, we placed the unit in a clear upper area to make use of the available space without encroaching on the adjacent opening.

The presence of the door limited our room for maneuver

A wall-mounted unit is never installed in isolation. Behind the unit, we must allow space for the refrigerant lines, wiring, and condensate drain.

Here, the proximity of the door frame required a particularly compact routing path.

In the photo, the line-set cover exits beneath the right side of the heat pump and then runs horizontally. This allowed us to avoid an unnecessarily long interior route while maintaining a discreet finish.

We also took the existing ceiling elements into account

The photo shows a detector installed on the ceiling above the heat pump area. When installing a system in an existing room, we must work around the elements already in place: detectors, light fixtures, outlets, trim, doors, cabinets, beams, and other equipment.

A good installation consists of integrating the heat pump into this environment without creating conflicts with the existing components.

Why the MIDEA 28 is well suited to this type of configuration

The Midea multizone range is designed to offer substantial flexibility in terms of indoor units. The manufacturer notably offers wall-mounted units, consoles, cassettes, and ducted solutions, with the option of combining different formats according to the building.

This flexibility is important in our projects on the South Shore, because two rooms in the same house may impose completely different constraints.

A bedroom may be perfectly suited to a wall-mounted air conditioner, whereas another space might require a different approach. The benefit of a multizone system is precisely to centralize heating and cooling production at the outdoor unit while adapting indoor distribution.

Midea All Easy Pro wall-mounted units offered in several capacities

Midea's documentation dedicated to wall-mounted units All Easy Pro offers several capacities, including 6,000, 9,000, 12,000, 18,000, 24,000 and 30,000 BTU/h. They use a 208/230 V, single-phase, 60 Hz power supply.

This diversity of capacities is important.

In a triple-zone installation, we do not necessarily seek to install three identical indoor units. Rather, we seek to select a capacity suited to each thermal load.

A small, well-insulated bedroom does not have the same needs as a living room with several windows or an open space exposed to the sun.

Three zones therefore do not mean three times the same capacity

This is one of the points we regularly explain to our clients in Montreal, Laval, Longueuil, on the North Shore and South Shore.

A multizone heat pump should not be sized simply by adding the property's total area and then dividing the result by three.

We should instead look at each zone separately:

• room area and volume;
• number of exterior walls;
• quality of insulation;
• orientation and sun exposure;
• window area;
• floor where the room is located;
• presence of a basement or garage;
• natural air circulation;
• actual use of the room.

A room upstairs may require much more cooling during the summer than a comparable room on the ground floor. Conversely, a space with more exterior surfaces may lose heat more quickly in winter.

A documented three-zone combination with SEER2 efficiency of up to 25

MIDEA's technical documentation for the range notably presents a three-zone combination Extreme Heat comprising three 6,000 BTU All Easy Pro indoor units and a condenser MO3HX-H18B-2A. This combination is associated with reference AHRI 215471457.

For this reference combination, Midea indicates:

• power supply of 208/230 V, single-phase, 60 Hz;
• indicated capacity of 19,000 BTU/h in cooling mode;
• indicated capacity of 20,000 BTU/h in heating mode;
• SEER2 of 25;
• EER2 of 15;
• indicated seasonal heating efficiency rating of 10,4;
• indicated heating capacity of 19,000 BTU/h at 5 °F, or approximately -15 °C, according to the manufacturer's performance table.

These values demonstrate the performance level the platform can achieve when used with a specific certified combination.

However, an important distinction must be maintained: AHRI ratings and efficiencies apply to specific combinations of indoor and outdoor units. Two installations marketed under the same MIDEA 28 family can therefore have different specifications depending on the capacities selected.

Inverter operation plays an important role in a multi-zone home

Midea uses inverter technology that allows the system to adjust its capacity as heating and cooling needs change. According to the manufacturer, the compressor and fans can adjust their operation when not all rooms require the same level of heating or cooling.

For the homeowner, this modulation is particularly beneficial in a triple-zone system.

Consider a typical situation in Carignan: in the late afternoon, a room on the sunny side may require more cooling while a bedroom on the opposite side has already reached its setpoint temperature.

A multi-zone system can adapt its operation to these varying needs rather than treating all rooms as one large space.

A technical point that is too often overlooked: condenser capacity remains decisive

One of the most common mistakes when comparing multi-zone quotes is adding up the BTUs listed for the indoor units and automatically treating that total as the capacity available simultaneously.

Midea documentation specifies that if the total load of the indoor units exceeds the nominal capacity of the outdoor unit, the actual capacity available to each unit may be reduced, and that this phenomenon is particularly noticeable in heating mode.

That is why we pay so much attention to Midea combination tables.

The right system is not necessarily the one with the highest total BTU rating on paper. It is the one whose configuration properly matches the property's needs.

From interior finishing to commissioning: what we monitor on a MIDEA triple-zone installation

The installation photographed in Carignan clearly illustrates our approach: an indoor unit must function properly, but it must also integrate neatly into the building.

A clean indoor line-set cover is part of the installation

On this MIDEA unit, the white line-set cover blends in with the unit and the wall.

This detail may seem primarily aesthetic. However, it is also functional.

The line-set cover groups and protects the components running between the indoor unit and the rest of the system. It also makes for a much neater installation than leaving a set of lines exposed.

In a bedroom, hallway, or living space, this finish is particularly important because occupants see the installation every day.

Condensate drainage must be planned from the outset

In cooling mode, an indoor unit removes moisture from the air and produces condensation water.

This water must be able to drain properly.

During our installations, we therefore plan the drain’s slope and route at the same time as the refrigeration lines. Poor drainage can cause problems unrelated to the quality of the heat pump itself: leaks, water accumulation, or more complicated maintenance.

That is why we never treat the drain as a detail to deal with at the end.

Commissioning a triple-zone system requires checking several circuits

A triple-zone system has more connections than a single-zone system.

Midea’s documentation specifically describes the technology SynchroConnectdesigned to make it easier to verify the correspondence between the wiring of the indoor units and the refrigeration lines connected to the condenser.

This feature clearly illustrates one of the particularities of multi-zone installations: when several circuits connect to a single outdoor unit, identifying and methodically checking each connection becomes essential.

Mistakes we want to avoid with a triple-zone heat pump

An installation like the one in Carignan also helps highlight several common mistakes.

Choosing the location of a head unit solely because the wall is clear

An indoor unit should be positioned according to airflow and the room’s layout, not solely based on ease of installation.

Installing a unit too close to an obstruction

Doors, ceilings, cabinets, curtains, or furniture can hinder airflow or maintenance. Each location must be evaluated individually.

Neglecting the interior routing of the lines

An improper route can leave a visually bulky finish for the entire life of the system.

Oversizing the indoor units

Adding more BTUs does not automatically improve comfort. Sizing must correspond to the actual heating loads.

Comparing heat pumps solely according to SEER2

The SEER2 is important, but it does not tell the whole story. For a heat pump used in Quebec, it is also necessary to examine heating performance, the AHRI combination, sizing, installation quality, and the use of the different zones.

Incentives: why we always verify the exact combination

A heat pump can perform well without necessarily being eligible for all available financial incentives.

To verify a subsidy, it is necessary to consider the exact condenser, exact indoor units, and certified AHRI combination.

In Midea’s documentation, the three-zone Extreme Heat combination mentioned earlier, for example, has the AHRI reference 215471457.

This reference is much more useful than simply mentioning “MIDEA 28” when it is time to verify an assistance program.

At AirGreen, we therefore always recommend confirming eligibility based on the actual combination installed and the program criteria in effect at the time of the work.

A discreet installation, but many technical decisions behind the photo

The photo of this MIDEA heat pump in Carignan ultimately shows something very simple: a white unit installed high on the wall, with a short section of white line-hide.

But behind this apparent simplicity are several important decisions: location, clearances, airflow direction, line-set routing, drainage, maintenance access, zone sizing, and coordination with the system’s two other units.

This is the approach we apply at AirGreen to our installations of wall-mounted and multi-zone heat pumps in Montreal, Laval, Longueuil, the North Shore and the South Shore.

In a three-zone system, each indoor unit is part of a whole. The project’s success therefore depends just as much on the quality of each of the three locations as on the performance of the outdoor condenser.

For this installation of MIDEA MIDEA 28 in Carignan, our objective was clear: to create three genuinely useful comfort zones while integrating the units cleanly into the building. The result visible in the photo reflects that priority exactly: a compact, structured installation suited to the available space.