Three zones, one outdoor unit: a MIDEA 28 installation adapted to the real constraints of a Lacolle home
In Lacolle, in Montérégie, we completed an installation that perfectly illustrates the value of a triple-zone heat pump when a house has several areas with different heating and cooling needs. For this project, our AirGreen team installed a MIDEA 28 multizone, with three indoor units allowing the comfort of different rooms to be controlled separately while using a single outdoor unit.
The multizone concept is particularly interesting in this type of residence: a single outdoor heat pump powers several indoor units, and each zone can have its own temperature setting. MIDEA documentation confirms that the indoor units can be controlled individually and that the system can heat or cool only the spaces in use, rather than treating the entire house uniformly.
In this Lacolleproject, the challenge was therefore not simply to install three wall-mounted air conditioners. We had to design a cohesive system: unit locations, refrigerant line routing, condensate drainage, electrical connections, communication between each indoor head and the outdoor unit, future service accessibility, and visual integration into the home.
A clean indoor installation despite limited wall space
The photo of our installation shows one of the elements that often requires much more thought than it might seem: the precise positioning of a wall-mounted unit.
Here, the MIDEA indoor head is installed in a relatively confined section of wall, near the ceiling and close to a corner. The technical routing was grouped into a white pipe cover, which protects the lines while maintaining a discreet finish.
This detail is important. A wall-mounted heat pump can be excellent on paper yet deliver disappointing results if its location is chosen solely based on the easiest place to drill.
We assess, among other things:
- the natural circulation of air in the room;
- the distance from the ceiling and adjacent walls;
- the ability to distribute air without creating an unpleasant draft directly on occupants;
- the routing of the refrigerant lines;
- the slope required for drainage;
- access to the filter and components during future HVAC maintenance;
- the aesthetic impact of the ducts and pipe covers;
- the total length of the connections between the indoor units and the outdoor heat pump.
In a triple-zone installation, these decisions must be made three times while remaining compatible with a single outdoor unit.
Why the MIDEA 28 was well suited to this triple-zone configuration
The MIDEA 28 belongs to a family of systems designed to allow different combinations of indoor units. The MIDEA multi-zone lineup supports several formats, including wall-mounted units, consoles, cassettes, and various ducted units. The manufacturer also presents its system as compatible with both ductless solutions and certain ducted applications.
For the version Extreme Heat corresponding to this capacity, the technical documentation identifies the outdoor unit MO4HX-H27B-2A, accompanied by the reference AHRI 215471460.
Although the documentation associates it with a platform capable of managing up to four zones, it can be configured with fewer indoor units when the selected combination complies with the manufacturer's rules. In this project in Lacolle, we use it as triple-zone heat pump.
Interesting performance for the Quebec climate
For the 27,000 BTU/h Extreme Heat configuration presented in the MIDEA brochure, the published specifications include:
- rated cooling capacity: 27,000 BTU/h;
- rated heating capacity: 27,000 BTU/h;
- SEER2: 23;
- EER2: 12.5;
- HSPF4: 10.5;
- power supply 208/230 V, single-phase, 60 Hz;
- heating capacity listed at 27,000 BTU/h at 5 °F, or approximately -15 °C;
-
outdoor sound level listed at 61 dB(A) in this combination.
These values are particularly useful when we compare several multi-zone heat pump solutions in Montreal, Laval, Longueuil, on the North Shore, or on the South Shore. They allow us to look beyond the maximum capacity listed on a sales sheet: seasonal efficiency, low-temperature heating performance, and the exact AHRI combination are equally important.
Three indoor units do not mean three times the capacity of the outdoor unit
This is a point we explain frequently when preparing our estimates.
In a multi-zone system, simply adding the rated capacity listed for each indoor unit does not make it possible to determine the actual output available in all situations.
MIDEA itself specifies that when the total load of the indoor units exceeds the outdoor unit's rated capacity, the actual capacity available to each unit may be reduced, a phenomenon that is particularly noticeable in heating mode.
It is therefore necessary to size a triple-zone heat pump as a complete system.
We look at, among other things:
The area and heat losses of each zone
A closed bedroom does not have the same needs as a large living room open to a kitchen. Window orientation, insulation, ceiling height and sun exposure also affect the load.
The likelihood that all three zones will simultaneously demand their maximum power
A multi-zone heat pump benefits precisely from the fact that needs vary from one room to another throughout the day.
The MIDEA system's inverter technology modulates the operation of the compressor and motors according to demand. When not all rooms require full capacity, the system can operate at partial load and reduce its consumption.
How the system performs in heating mode
In Québec, we never size a heat pump solely according to its summer cooling capacity. The available capacity as the outdoor temperature drops is essential, especially in a municipality like Lacolle, where the heat pump may be used intensively during the winter.
A fourth available connection does not automatically mean a fourth zone can be added later
The MIDEA platform corresponding to this capacity offers great flexibility, but it would be incorrect to conclude that an additional indoor unit can always be added simply because a connection is available on the outdoor unit.
Before making any future changes, we must check:
- the combination of units authorized by MIDEA;
- the sum of the indoor capacities;
- the maximum line length;
- the pipe diameters;
- the amount of refrigerant;
- the electrical configuration;
- the impact on the capacity simultaneously available in the other zones.
That is precisely why the manufacturer's combination tables are part of our design work.
The routing of the lines is part of the quality of an HVAC installation
This photo of the installation in Lacolle also shows an aspect we consider essential: the work must remain neat once the panels have been closed and the tools removed.
The pipe cover visible near the indoor unit, conceals the technical passage while providing a uniform finish. Behind this type of finish are several components that must be installed correctly: insulated refrigerant lines, communication wiring and, depending on the route chosen, condensate drainage.
A poor route can lead to:
- water buildup in the drain;
- vibrations;
- noise in the wall;
- deteriorated insulation around the lines;
- an installation that is difficult to maintain;
- an interior finish that is much more visible than necessary.
Our goal is therefore not merely to get the heat pump working on the day of commissioning. We aim to deliver a durable and accessible HVAC installation.
Commissioning is just as important as installing the units
After the physical installation, a multizone heat pump requires methodical commissioning.
Our technicians must specifically check the refrigerant connections, perform the appropriate evacuation procedure, verify communication between the units, and test each zone individually.
The MIDEA line also includes a feature called SynchroConnect. According to the manufacturer, this technology can diagnose the status of the connections between the units and help synchronize the refrigerant lines with the corresponding wiring.
This feature is particularly useful on a multizone system, where several pairs of pipes and several cables converge at the same outdoor unit. However, it does not replace an orderly installation, clear labeling, and commissioning checks performed by the technician.
This Lacolle project shows what to check before choosing a triple-zone heat pump
An installation like this is relevant well beyond Lacolle. We encounter the same questions on projects in Montreal, Laval, Longueuil, on the North Shore and the South Shore several bedrooms, one floor warmer than another, a home extension, a basement that is difficult to heat or cool, or occupants who want different temperatures.
A multizone heat pump can be an excellent solution, but only if it is chosen for the right reasons.
The mistakes we recommend avoiding
Choose the outdoor capacity solely by adding the BTUs of the three heads
The selection must comply with the manufacturer’s combinations and take actual simultaneous demand into account.
Install the indoor units where the lines are easiest to route outside
Air distribution, comfort, and future maintenance must be considered before ease of drilling.
Neglect drainage
An incorrect slope or poorly designed route can turn a functional installation into a recurring condensation problem.
Rely solely on the advertised number of zones
An outdoor unit that can support four zones is not automatically the best choice for four large rooms. The available capacities must be analyzed together.
Compare two heat pumps solely by their price
The SEER2heating performance, AHRI number, noise level, combination options, installation quality, and after-sales service directly influence the system’s true value.
A specific AHRI reference also makes subsidy verification easier
For this 27,000 BTU/h MIDEA Extreme Heat platform, the brochure associates the reference combination with number AHRI 215471460.
This is an important detail for homeowners looking for a heat pump subsidy in Quebec.
Eligibility for a program such as LogisVert or any other financial assistance must nevertheless be verified based on:
- the exact combination of installed units;
- the applicable AHRI number;
- the type of building;
- the requirements of the program in effect at the time of the work.
We therefore avoid promising a subsidy amount simply because a unit belongs to a high-efficiency heat pump family. The installed combination and its certification are decisive.
The desired result: three comfortable spaces without multiplying outdoor units
The practical advantage of a triple-zone installation like the one in Lacolle is the ability to manage several rooms with a single outdoor unit.
This reduces the number of visible pieces of equipment around the property and provides more precise control of the indoor temperature.
A bedroom may require less heating during the day, while a living area may need more capacity. Each indoor unit can be adjusted according to its use, which reflects the very principle of the multi-zone system described by MIDEA.
For the homeowner, this flexibility is generally more useful than imposing the same temperature throughout the house.
Our approach at AirGreen for multi-zone installations
At AirGreen, we place as much importance on project design as on the choice of brand.
Before a MIDEA heat pump installation, we analyze the spaces to be conditioned and look for a logical route for each indoor unit. Once the equipment has been selected, our job is to maintain this logic down to the smallest details: head placement, lines, drainage, connections, evacuation, startup, and operation checks for each zone.
The photo of this Lacolle project clearly illustrates this approach. The indoor unit is integrated into a relatively tight space, the lines are concealed in a white finish, and the overall result remains visually understated.
For a triple-zone heat pump in Montreal, Laval, Longueuil, on the North Shore, the South Shore, or elsewhere in MontérégieThe choice of equipment is only one part of the project. Sizing, the combination of units, and the quality of the on-site work largely determine the comfort the homeowner will actually enjoy over the coming years.