Installation of a MIDEA 28 dual-zone heat pump in Saint-Marc-sur-Richelieu, in Montérégie

A two-zone installation where the placement of the wall-mounted unit made all the difference

In Saint-Marc-sur-Richelieu, we completed an installation of a MIDEA 28 two-zone heat pump in a residence where choosing the location of the indoor units required particular attention. The photo taken during the work clearly illustrates a reality we regularly encounter in HVAC installation: the space available for a wall-mounted unit is not always wide, clear, and perfectly symmetrical.

Here, the MIDEA indoor unit was installed very high on the wall, immediately beneath the ceiling. To the right of the unit, the opening used to route the connections is still visible, indicating that the photo was likely taken during the installation phase or before the wall was completely finished. This type of image is interesting because it shows what actually happens behind a clean finished installation: refrigerant lines, communication wiring, condensate drainage, and the wall penetration must all be planned within a relatively confined space.

In this Saint-Marc-sur-Richelieu project, the configuration selected was a two-zone heat pump, meaning a single outdoor system serving two distinct indoor zones.

The MIDEA multi-zone principle is specifically designed for this use: a single outdoor unit can be connected to several indoor units, each of which can be controlled and adjusted separately according to the needs of the room it serves.

This independence between zones is one of the main reasons to choose a two-zone heat pump rather than a single oversized wall-mounted unit that would attempt to serve several rooms remotely.

Why two zones made more sense than a single wall-mounted unit

In a house, air does not automatically move where we would like it to go.

A unit installed in a living room does not necessarily cool a bedroom located behind a door properly. A wall-mounted head installed on the ground floor does not ensure a uniform temperature upstairs either. Corridors, stairwells, closed doors, large glazed areas, and differences in sun exposure completely change the actual distribution of comfort.

That is where dual-zone makes sense.

With two indoor units, we can assign one zone to each of the residence's most important areas. Occupants can then adjust the temperature of each space rather than seeking a permanent compromise.

MIDEA also indicates that individual control makes it possible to heat or cool only the zones in use, without necessarily treating the entire home at the same level.

In a municipality like Saint-Marc-sur-Richelieu, where homes have a wide variety of layouts, this flexibility can be particularly relevant: an expanded bungalow, a two-story residence, a home with a finished basement, an open-concept area combined with enclosed bedrooms, or a space added more recently.

What the photo teaches us about this MIDEA installation

The visible wall-mounted unit was positioned very close to the ceiling, in an area where every centimeter mattered.

This positioning makes it possible to:

• keep the wall available for furniture;
• place the air outlet at a height that is favorable for covering the room;
• limit the unit's visual impact;
• bring the pipe passage closer to the upper part of the wall;
• facilitate horizontal air distribution throughout the space.

However, installing a wall-mounted unit high on the wall does not simply mean pushing it as close to the ceiling as possible. The clearances specified by the manufacturer must be maintained, and it must be ensured that return air can circulate properly above the unit.

We must also think about future maintenance.

A wall-mounted heat pump may eventually need to be opened to clean the filters, turbine, coil, and drain pan. An installation that works well on the first day but becomes almost impossible to maintain a few years later is not a good installation.

The visible passage to the right of the unit: an important construction detail

In the photograph, the right side of the wall is not yet completely finished around the wall penetration.

This detail helps explain an aspect that is often invisible once the work is complete.

Several essential components generally pass behind an indoor unit:

• the refrigerant lines;
• the pipe insulation;
• the communication cable;
• the power supply according to the configuration;
• the condensate drain pipe.

Before even drilling through the wall, we need to determine which direction these components will exit, whether they will immediately descend outside, whether they will run along a façade, and how they will connect to the outdoor unit.

For a dual-zone installation, this planning becomes even more important because two indoor units must connect back to the same condenser.

Poor routing can quickly turn an installation that was meant to be discreet into an unnecessarily long and visually cumbersome duct network.

The MIDEA 28: a multizone platform that enables multiple configurations

The technical documentation for this MIDEA family is not limited to wall-mounted units. It presents a range that can combine several types of indoor units, including wall-mounted units, consoles, cassettes, ducted models, and air-handling units.

This flexibility is useful when a residence is not suited to two identical wall-mounted heads.

For example, we may encounter a project where:

• a wall-mounted unit is perfectly suited to the living room;
• a small ducted unit is better suited to several bedrooms;
• a cassette integrates more seamlessly into a large space;
• a console is preferable on a low wall.

In the project presented here, the photo shows a MIDEA wall-mounted unit, which remains one of the most direct solutions for creating an independent zone in a room or on a floor.

Inverter technology adapted to the variable needs of two zones

Multizone operation is closely linked to Inverter technology.

According to MIDEA, the system can vary its capacity as the temperature changes by adjusting the operation of the compressor and fan motors. When not all zones require their full capacity, the unit can operate at partial load and reduce its energy consumption.

This is particularly relevant in a dual-zone installation.

Let us take a concrete example: the main zone of the house may require more cooling in the afternoon while the second zone is almost inactive. A few hours later, the first zone may reach its setpoint while the second begins to require more heating or cooling.

The system therefore does not always need to deliver its full rated capacity.

This modulation generally allows for more gradual operation than a conventional system that operates solely through on-off cycles.

The documented performance of the MIDEA 28 in Extreme Heat configuration

For the 27,000 BTU version of the MIDEA family documented in the brochure, the Extreme Heat outdoor unit is identified by model MO4HX-H27B-2A. MIDEA also publishes the reference number AHRI 215471460 for a reference combination with All Easy Pro wall-mounted units.

For this particular certified combination, the documentation indicates:

• power supply of 208/230 V, 1 phase, 60 Hz;
• nominal cooling capacity of 27,000 BTU/h;
• nominal heating capacity of 27,000 BTU/h;
• SEER2 of 23;
• EER2 of 12.5;
• HSPF4 of 10.5;
• heating capacity indicated at 5 °F (-15 °C): 27,000 BTU/h;
• indicated maximum outdoor airflow: 2,148 CFM;
• published outdoor sound level: 61 dB(A).

However, these figures must be interpreted correctly.

They correspond to a specific AHRI combination, and not automatically to all possible configurations of two indoor units. In a multi-zone system, the exact combination of indoor heads can change the certified performance data.

That is why, at AirGreen, we always check the complete combination rather than relying solely on the commercial name “MIDEA 28.”

The outdoor unit's dimensions also matter in planning

For this same 27,000 BTU Extreme Heat version, the brochure indicates net dimensions of 946 × 410 × 810 mm, or approximately 37 1/4 × 16 1/8 × 31 7/8 in.

In a project in Saint-Marc-sur-Richelieu, these dimensions directly affect the choice of the outdoor location.

We must plan for:

• sufficient clearance around the condenser;
• access for maintenance;
• a position that limits snow accumulation;
• a location that does not block a window or passageway;
• a logical route for both line sets;
• a reasonable distance from bedrooms and living areas.

Choosing the support or base for the outdoor unit is also part of the work. In Quebec, a heat pump installed too close to the ground can become vulnerable to snow and ice in winter.

Dual-zone does not mean twice the outdoor capacity

A common misconception is to add the nominal capacities of the two indoor units and assume that the condenser will automatically provide this total capacity continuously.

This is not necessarily the case.

MIDEA specifies in its combination guidelines that when the total nominal capacity of the indoor units exceeds that of the outdoor unit, the actual capacity available to each unit may be reduced, especially in heating mode.

This means that good multi-zone design requires thinking about the simultaneity of needs.

Two zones can have very different loads

A south-facing zone with several windows may require much more cooling in the afternoon.

A smaller, shaded room may require much less energy at the same time.

Conversely, the second zone may become the priority at night.

We must therefore choose capacities based on the building and its actual use, not merely by adding up figures on a technical data sheet.

Sizing remains more important than the simple number of BTUs

When preparing a quote for a heat pump in Saint-Marc-sur-Richelieu, we consider in particular:

• the area of each zone;
• the insulation level;
• the number of windows;
• sun exposure;
• ceiling height;
• the floor where the room is located;
• communication between spaces;
• internal heat sources;
• winter heating needs.

Two rooms of the same size may require different capacities.

Conversely, systematically installing the largest possible unit does not necessarily improve comfort.

An oversized heat pump can reach its setpoint too quickly, operate for shorter periods, and provide less consistent summer dehumidification.

Condensate management: something that should never be improvised

The photograph shows an installation very close to the ceiling, making drain planning particularly important.

In air conditioning, moisture in the air condenses on the indoor coil and must be drained outdoors or to a suitable drain.

When conditions allow, we aim to create a natural slope that enables gravity drainage.

We avoid the following whenever possible:

• back-pitches;
• crushed pipes;
• sections where water can remain stagnant;
• unnecessarily complex routes;
• condensate pumps when gravity is sufficient.

A small drainage error may not be visible on the day of commissioning, but it can cause drainage problems several months later.

The electrical installation must match the exact outdoor unit

The documentation for the 27,000 BTU version mentioned above indicates a 208/230 V single-phase power supply.

On site, however, we must verify the specific electrical requirements of the installed model, including:

• the circuit breaker rating;
• the wiring gauge;
• the circuit protection;
• the manufacturer's requirements;
• the capacity available at the electrical panel.

We never determine these elements based solely on a BTU figure.

The exact model and its nameplate remain the final references.

From the worksite photo to everyday comfort: what we seek at AirGreen

A successful installation should become almost invisible

The photo of this installation in Saint-Marc-sur-Richelieu still shows certain elements of the worksite, including the passage area to the right of the unit.

Once the connections are complete and the finishing work is done, the goal is exactly the opposite: to make everything technical as invisible as possible.

The homeowner should mainly see a neatly installed unit and get the desired temperature.

That is why we place so much importance on:

• the alignment of the wall-mounted unit;
• the routing of the lines;
• the choice of the exit point;
• the quality of the supports;
• equipment accessibility;
• during commissioning.

The SynchroConnect function facilitates work on compatible multi-zone systems

The MIDEA brochure also presents SynchroConnect technology, which allows the system to check the correspondence between certain refrigerant and electrical connections and facilitate their synchronization after connection.

On a multi-zone system, this function provides useful assistance to the installer.

However, it does not replace good installation practices.

Each circuit must always be connected properly, the lines protected, the connections tightened according to specifications, and the vacuum pulled correctly.

A single outdoor unit, with less clutter around the house

Another advantage of a dual-zone system is the ability to heat or cool two spaces with a single outdoor unit.

MIDEA also highlights the reduction in occupied outdoor space when several indoor units are connected to a single condenser.

For a home with limited available facade space, this can make a real difference.

Two single-zone systems would require two condensers, two electrical circuits, and two outdoor locations.

A dual-zone configuration can therefore provide a much cleaner installation.

What about subsidies such as LogisVert?

For any MIDEA heat pump installed in Quebec, eligibility for financial assistance must be verified according to the program in effect and, above all, the exact combination of equipment.

The brochure provides several specific AHRI references. For the previously mentioned 27,000 BTU Extreme Heat model, the reference combination with wall-mounted units is associated with AHRI number AHRI 215471460.

It should therefore not be concluded that an installation is eligible solely because the condenser belongs to a given MIDEA range.

We verify:

1. the outdoor model;
2. the indoor models;
3. the certified combination;
4. the corresponding AHRI number;
5. the program criteria applicable at the time of installation.

This verification is particularly important when financial assistance influences the homeowner's final choice.

The mistakes we seek to avoid with a dual-zone heat pump

Installing both units simply where the pipes will be shortest

The refrigerant line route is important, but indoor comfort remains the priority.

A poorly positioned head may have a very short route and still distribute air in the wrong place.

Neglecting the return air above the unit

A wall-mounted unit installed high up must retain the necessary clearance to breathe properly.

Automatically choosing two identical capacities

The two zones do not necessarily have the same needs.

Failing to plan for future maintenance

Access to the filters, coil, and blower wheel must remain possible.

Buying based on the advertised performance without verifying the AHRI combination

On a multizone system, certified performance depends on the precise combination of equipment.

Ignoring the simultaneous demand of both zones

A configuration that works very well when the zones are used at different times may behave differently when both demand their maximum capacity simultaneously.

A particularly interesting solution for the South Shore and Montérégie

This MIDEA 28 dual-zone heat pump installation in Saint-Marc-sur-Richelieu represents the type of project we regularly carry out in Greater Montreal.

The same principles apply in Longueuil, Boucherville, Beloeil, Chambly, Saint-Bruno, Carignan, Montréal, Laval, and the North Shore.

The product matters, but the result depends enormously on the installation.

A properly selected heat pump installed in the wrong location can deliver disappointing results. Conversely, a correctly sized configuration, with two intelligently positioned zones and a clean installation, can provide much more uniform comfort throughout the home.

At AirGreen, we therefore approach each project as a combination of four elements: sizing, positioning, installation quality, and commissioning.

The MIDEA 28 offers a flexible multizone platform; our job is then to adapt it properly to the building.