In Chambly, a precisely integrated dual-zone installation beneath exposed piping
An installation of a dual-zone heat pump becomes especially attractive when two spaces need to be heated and cooled independently, without multiplying the number of outdoor units. This is exactly the principle selected for this installation in Chambly, on the South Shore, with a MIDEA MIDEA28 multi-zone heat pump and wall-mounted indoor units.
The photo taken during our work clearly shows an aspect that is often encountered in the field but much less often in technical specifications: the ideal location for an indoor unit is not simply “an empty wall.” Here, several horizontal pipes run very close to the ceiling. The Midea wall-mounted unit therefore had to be positioned under this existing piping, while maintaining a logical layout for air circulation, connection routing, condensate drainage, and future access for maintenance.
This is the type of situation where the quality of an HVAC installation comes down to the details.
A multi-zone system: one outdoor unit, two comfort zones
The Midea multi-zone system is based on a simple principle: one outdoor unit serves multiple indoor units, and each can be controlled separately according to the desired temperature in its space. Midea documentation specifically states that the units can be adjusted and programmed individually.
In this MIDEA28 dual-zone installation in Chambly, this configuration offers a very practical advantage. Instead of installing two outdoor condensers for two zones, we can centralize heating and cooling production around a multi-zone outdoor unit, then distribute this capacity to two indoor units.
This notably helps reduce outdoor clutter and better adapt comfort to the actual use of the rooms. Midea also points out that zoned operation makes it possible to heat or cool only the spaces in use rather than systematically conditioning the entire home.
For a homeowner in Chambly, Longueuil, Boucherville, or elsewhere on the South Shore, this independence becomes especially valuable when the two zones have different sun exposures, dimensions, or occupancy habits.
What the project photo reveals about our installation method
In the photo, the Midea indoor unit is installed on a wall surface with a textured architectural finish, immediately below several exposed pipes. The available space in the upper part of the wall was therefore limited.
We had to consider the ceiling piping, installation height, clearance around the unit, and the room’s overall appearance simultaneously.
The visible result is a unit installed in a clear section of wall without encroaching on the existing piping. This arrangement also keeps the front panel and air outlet accessible. This is important: a wall-mounted heat pump must be able to be opened later for filter cleaning, heat exchanger inspection, and any necessary HVAC maintenance.
During installation, our team must also plan what will be practically invisible once the work is complete: the refrigerant line route, communication wiring, electrical supply, drain connection, and drain slope.
Why ceiling height and obstacles really matter
Placing an indoor unit as high as possible is not automatically the best strategy.
An unit placed too close to a pipe, beam, or ceiling can make air intake more difficult and, above all, make maintenance much more challenging. Conversely, a unit installed too low may distribute air less effectively throughout the room and become more visually intrusive.
On this Chambly project, the presence of exposed piping therefore required a carefully considered layout rather than an arbitrarily chosen position.
This is also why an on-site assessment remains so valuable. The dimensions of a room tell only part of the story. The building’s structure, accessible walls, possible routes to the exterior, existing obstacles, and condensate management can significantly change the installation strategy.
MIDEA28: a heat pump designed for Quebec’s climate
The MIDEA28 series is not limited to summer air conditioning. Midea’s Quebec documentation presents the range as a single-zone or multi-zone solution using A2L R-454B refrigerant, certified Cold Climate V6.1, with heating operation down to -30 °C. Depending on the combinations, the range reaches up to 27.4 SEER2 and up to 13.5 HSPF2.
This low-temperature operating capability is particularly relevant in Chambly and the Greater Montreal area. A heat pump used in Quebec must be selected for conditions far more demanding than a simple hot day in July. It must also help provide heating when the outdoor temperature drops sharply.
Inverter technology allows the compressor to modulate its operation rather than operating only in a full-power on-off cycle. Midea describes this modulation as adjusting capacity based on temperature variations and the actual load.
This modulation is particularly logical in a dual-zone system, since the needs of the two spaces are not always identical at the same time.
The technical data you really need to look at on a multizone MIDEA28
The name “MIDEA28” refers to a product line and, by itself, is not enough to determine the exact capacity of the condenser used on each job. Sizing depends on the connected indoor units and the heating requirements of the zones.
Midea's Extreme Heat documentation lists the MO4HX-H27B-2A, a 27,000 BTU/h outdoor unit that can serve one to four zones. This ductless configuration has AHRI number 215471460. It offers a 27,000 BTU/h nominal cooling capacity, a 27,000 BTU/h nominal heating capacity, a SEER2 of 23, an EER2 of 12.5, and an HSPF2 Region IV of 10.5. At -15 °C, Midea still specifies a 27,000 BTU/h nominal heating capacity, with a COP of 2.0.
The supplied brochure also confirms AHRI number 215471460 for this Extreme Heat combination and its nominal capacity of 27,000 BTU/h.
For installers, the electrical and refrigeration specifications are just as important. For this 27,000 BTU variant, Midea specifies, among other things, an MCA of 30 A, a maximum protection of 35 A, a 208/230 V, single-phase, 60 Hz power supply, AWG 14-4 connection wiring, and R-454B. The available refrigeration ports vary depending on the capacity of the connected indoor units.
These values illustrate why we never size the breaker, wiring, or refrigerant lines “by habit.” The nameplate and documentation for the actual installed model must always determine the final connection.
Sizing the two zones is just as important as choosing the brand.
With a dual-zone heat pump, adding two BTU values and automatically choosing the next larger condenser can lead to an incorrect configuration.
Midea publishes combination tables precisely because not all indoor-unit combinations perform the same way. The documentation also specifies that when the total load of the indoor units exceeds the outdoor unit’s rated capacity, the capacity actually available to each unit may be reduced, particularly in heating mode.
At AirGreen, we therefore view the layout as a complete system: the spaces’ heating load, the capacity of the indoor units, the permitted combination, line length, condenser location, and winter conditions.
A bedroom, a large common area, or a room with extensive glazing does not automatically require the same capacity simply because the floor areas appear similar.
What this MIDEA28 installation in Chambly can teach a homeowner before choosing a heat pump
A beautiful indoor unit can never compensate for poor placement. The Chambly project demonstrates this well: the work begins with understanding the building, followed by choosing the system, not the other way around.
Errors we aim to avoid in a dual-zone installation
Several details deserve particular attention during a multi-zone heat pump installation:
- Choose BTUs based solely on floor area without considering insulation, windows, exposure, and room layout.
- Place the wall-mounted unit too close to the ceiling or an obstacle, which can hinder access and make cleaning more difficult.
- Neglect the condensate drain slope, which can lead to improper drainage or water problems.
- Use a “standard” pipe diameter without checking the model. In the MIDEA28 series, diameters vary according to the capacity of the indoor unit.
- Ignore the multi-zone combination rules, particularly when connecting multiple capacities to the same condenser.
- Approximating the electrical circuit sizing instead of complying with the prescribed MCA and maximum protection.
- Considering only air conditioning when, in Quebec, low-temperature heating capacity is crucial.
- Forgetting to plan for future maintenance access, turning a simple cleaning into an unnecessarily complex service call.
These points apply in Chambly, as well as to our heat pump installations in Montreal, Laval, Longueuil, on the North Shore, and on the South Shore.
A useful technology: SynchroConnect
Multi-zone installations have more connections than a single-zone heat pump. Each indoor unit has its own refrigerant lines and communication wiring, which increases the number of connections to manage at the outdoor unit.
Midea integrates SynchroConnect technology into its multi-zone platform. According to the brochure, the system can diagnose connections and synchronize the refrigerant lines and wiring when connections have been made to different ports.
This obviously does not replace methodical installation, leak testing, evacuation, and commissioning. However, it is an additional tool for reducing the risk of errors in a system with multiple indoor units.
Dual-zone comfort is not simply “two air conditioners on one compressor”
The main benefit of a MIDEA28 multi-zone system lies in its comfort management.
The two indoor units can have different set temperatures. A lightly occupied zone can be set differently from a space used all day. The Inverter then adjusts system output according to demand.
Midea documentation also highlights the variety of compatible indoor units: wall-mounted units, consoles, cassettes, and ducted units. The platform can therefore be adapted to very different architectural constraints.
For this Chambly project, the photographed wall-mounted unit was a particularly logical solution because it could be installed directly beneath the existing ducts without requiring the creation of an air distribution network.
An important note about LogisVert and heat pump rebates
The MIDEA28 has features sought in energy-efficiency programs, including ENERGY STAR and Cold Climate V6.1 certifications for applicable configurations.
However, this does not mean that a subsidy amount should be announced without verifying the AHRI number, the exact unit combination, and the installation date.
Hydro-Québec specifies that the lists of eligible heat pumps and the amounts may change, and that the list applicable at the time of installation must be consulted. For installations carried out on or after November 26, 2025, Hydro-Québec specifically requires ENERGY STAR certification for eligibility for LogisVert financial assistance.
That is why we place so much importance on the AHRI number in a quote and in the final documentation. Hydro-Québec also points out that this number is among the important information used to identify and validate a heat pump when applying for financial assistance.
What we take away from this installation in Chambly
This MIDEA MIDEA28 dual-zone heat pump installation in Chambly clearly illustrates how we approach an HVAC project: adapting the equipment to the building instead of trying to adapt the building to a standardized installation.
The exposed piping along the ceiling created a real constraint for the wall-mounted head visible in the photo. We therefore planned the location to integrate the unit neatly into the available space, preserve its accessibility, and allow for logical air distribution.
Behind this relatively discreet white unit lies a whole set of technical decisions: zone sizing, choice of multizone combination, unit placement, condensate management, refrigerant piping route, electrical connection, evacuation, system inspection, and commissioning.
This invisible part of the work largely determines the quality of an installation over the long term.
For a homeowner comparing a Midea heat pump, a dual-zone solution, or several heating and cooling options in Chambly, Montreal, Laval, Longueuil, on the South Shore, or the North Shore, we always recommend having the building assessed before determining the units’ capacities.
At AirGreen, we carry out HVAC installations by taking into account both equipment performance and the realities of the job site. A properly selected heat pump deserves an equally rigorous installation.