Installation of a MIDEA EVOX G3 central heat pump in Rosemont–La Petite-Patrie, Montreal

A compact urban installation between masonry, an exterior staircase, and limited service space

In Rosemont–La Petite-Patrie, installing a central heat pump often requires a different approach from that used on a property with a large yard. Here, every square foot of outdoor space matters. Stairs, balconies, fences, brick walls, foundation openings, pathways to the yard, and existing electrical equipment can all influence where we can actually install the outdoor unit.

That is exactly what this AirGreen project with a MIDEA EVOX G3 central heat pump demonstrates.

In the project photo, the outdoor unit is installed against a façade of typically Montreal red brick, immediately beside a staircase and a metal structure painted green. The condenser does not rest on the ground: we placed it on a metal bracket attached to the foundation, which completely frees the space beneath the unit and keeps it at a height suited to our winter conditions.

The result looks simple once the work is complete. Yet several constraints had to be addressed at the same time: maintaining the passage around the staircase, avoiding placing the fan too close to the metal structure, preserving access to the service panel, taking the existing vents in the masonry into account, and installing the electrical disconnect nearby without unnecessarily cluttering the façade.

Midea's documentation presents the EVOX G3 as a range of inverter ducted central systems designed to facilitate the modernization of existing heating installations.

Why this photo illustrates the challenges of an HVAC installation in Montreal

In a neighborhood like Rosemont–La Petite-Patrie, we cannot simply choose the location where the refrigerant line would be shortest.

The heat pump must integrate with the house as it already exists.

On this project, three constraints are immediately visible.

The first is the green metal structure located very close to the condenser's façade. It was not supposed to become an obstacle to air discharge or complicate access to the unit.

The second is the presence of several technical elements on the wall, including two visible openings or vents to the right of the heat pump.

The third is the limited space at ground level. Installing the unit on a slab would have occupied more of the small available area and brought it closer to vegetation and winter accumulation.

We therefore opted for an elevated wall-mounted installation.

The wall bracket is not only used to save space

In an urban environment, one might think that the support's main advantage is simply aesthetic or practical.

Its role is much more important.

When a heat pump operates in heating mode, the outdoor heat exchanger can accumulate frost. The system then periodically initiates a defrost cycle. The resulting water must be able to drain beneath the unit.

A unit installed very close to the ground can gradually become surrounded by ice, snow, or debris.

By positioning this MIDEA EVOX G3 higher, we create open space beneath the unit, allowing for:

• better management of defrost water;
• greater distance from the snow;
• easy visual access beneath the condenser;
• easier maintenance around the support;
• less contact with ground vegetation.

In Montreal, this height is particularly relevant for a heat pump used as the main component of the central heating system.

The front fan had to remain unobstructed despite the staircase's proximity

The EVOX G3 visible in the photo is an outdoor version with a single large front fan.

The latter faces the open space, while the stair structure remains lateral to the main discharge area.

This orientation is important.

Midea describes the EVOX G3 as using a horizontal discharge paired with a vertical heat exchanger. The manufacturer explains that this architecture promotes more uniform airflow across the heat exchanger's surface and aims to maintain good heat-exchange efficiency as the outdoor temperature drops.

A poorly oriented installation could cause the unit to blow air directly against:

• a fence;
• an adjacent wall;
• a solid staircase;
• a terrace;
• another piece of equipment.

When the discharged air becomes confined, some of it can return toward the condenser. We specifically want to avoid this phenomenon.

A distinctive feature of Rosemont–La Petite-Patrie: equipment must coexist with everyday traffic

On several properties in the area, the outdoor stairs are used daily.

A heat pump installed too far from the wall can therefore become an obstacle, reduce the width of a passageway, or make it more difficult to move around the house.

Here, the condenser is positioned near the façade and above ground level, which limits its footprint.

We have also preserved access to the unit's service side. This detail is essential for future service work.

An installation must be designed not only for the day we start it up, but also for the technician who may need to access it five, ten, or fifteen years later.

The electrical disconnect is positioned nearby without obstructing service

To the right and below the heat pump is the outdoor electrical disconnect.

It remains accessible independently of the stairs and is not hidden behind the machine.

The electrical run is also relatively compact.

With a professional HVAC installation, we want the technician to be able to quickly:

• locate the power supply;
• isolate the heat pump;
• access the service panel;
• perform work without having to dismantle part of the outdoor landscaping.

These details are not always shown in large print in a quote, but they have a real impact on the quality of a project.

The exact capacity cannot be identified from the photo alone

The photograph clearly shows a relatively compact single-fan Midea outdoor unit, but the complete number shown on the nameplate is not legible enough to identify its capacity with certainty.

We therefore do not want to arbitrarily claim 24,000, 30,000, or 36,000 BTU/h simply based on its dimensions.

The EVOX G3 range includes several combinations. The Midea technical data sheet notably presents:

The brochure also presents the heating capacities at approximately -15 °C for each of these configurations.

The exact combination of the indoor unit and condenser must therefore always be verified before comparing performance ratings.

Up to 19 SEER2, but heating performance is just as important

For a central heat pump installed in Quebec, SEER2 tells only part of the story.

Midea publishes performance ratings for this entire range of up to 19 SEER2, 12.5 EER2, 10.8 HSPF2, and a COP of up to 2.14 at 5 °F, or approximately -15 °C, depending on the combination.

For our customers in Rosemont–La Petite-Patrie, we pay particular attention to winter performance.

A unit that operates extremely efficiently in cooling mode but quickly loses capacity as the temperature drops is not necessarily the best choice for Montreal.

An EVOX G3 designed to operate down to -30 °C

Midea states that its EVOX G3 Extreme Heat platform offers continuous operation down to -30 °C. The documentation also indicates, under certain test conditions, up to 100% heating capacity at approximately -25 °C. Midea specifies that some of these values come from tests of a three-ton system; they should therefore not be automatically applied to all capacities.

This distinction is important.

A heat pump may be capable of operating at -30 °C without necessarily covering 100% of a particular building's heat losses at that temperature.

We must therefore always compare:

the heat pump's low-temperature capacity with the property's actual heat losses.

M-Powevi technology and heating in extreme cold

Midea uses its M-Powevi compressor technology to support performance in extreme cold conditions.

According to the manufacturer, the system supplies intermediate-temperature vapor to the compressor, which increases the total amount of compressed refrigerant and improves heating performance when temperatures are very low.

For the user, the benefit is simpler to understand: the unit is designed to retain more capacity when outdoor conditions become challenging.

The condenser is visible in the photo, but the quality of a central heat pump also depends on the ductwork

A house can have an excellent heat pump and poor airflow

In a central system, we cannot evaluate the system solely by looking at the outdoor unit.

Inside, the air handler must push air through a complete duct network.

The result depends in particular on:

• the diameter and shape of the ducts;
• the return-air size;
• the transitions around the indoor unit;
• filtration;
• the number of registers;
• the system's static pressure;
• the airflow required by the heat pump.

In older properties in Rosemont–La Petite-Patrie, the system may have been built for an older furnace or modified several times over the course of renovations.

That is why we never consider the new unit as simply a box replacing the old one.

Computational Constant Airflow 2.0: an interesting advantage for existing ductwork

Page 8 of the Midea documentation presents Computational Constant Airflow 2.0 technology.

The principle is to adjust the output and fan speed to maintain airflow as system conditions change.

In the example provided by Midea, the system can maintain 1,200 CFM up to 1.2 in. of static pressure.

The platform also offers up to 60 airflow adjustment levels.

For a renovation project, this flexibility can be very useful.

But we must never interpret this technology as permission to leave an inadequate duct system as is.

If we find a significant restriction, we always look for its cause: insufficient return air, a filter that is too small, a crushed duct, a poorly designed plenum, or another problem.

Airflow can range from less than 700 to more than 1,800 CFM depending on the equipment

The EVOX G3 technical data sheet shows very different airflow rates depending on the indoor unit’s capacity.

The published values range approximately from 618 CFM to more than 1,800 CFM, depending on the unit and selected speed.

This variation explains why system sizing is essential.

A higher-capacity heat pump generally requires more air. If the duct system cannot move it, we can create noise, excessive pressure, and uneven distribution.

The EVOX G3 indoor unit can be configured in several ways

In Montreal basements, we often have to work around low ceilings, beams, plumbing pipes, or equipment installed very close to the old furnace.

Midea designed the EVOX G3 air handler with a modular architecture allowing multiple orientations.

The brochure notably presents:

• upflow;
• downflow;
• right horizontal;
• left horizontal;
• different low-boy configurations.

This design is intended to facilitate integrating the unit into complex mechanical spaces.

Widths suited to several older central installations

Midea also offers indoor units with approximate widths of 14.5 to 21.5 inches, depending on capacity, to facilitate certain conversions from an existing furnace.

This can reduce the extent of plenum modifications.

However, you must always check whether the existing ducts are suitable for the new unit’s airflow. Even when two units have the same physical width, their CFM requirements can differ significantly.

The auxiliary heating can reach 25 kW depending on the application

The range includes auxiliary electric heating kits that can reach 25 kW and operate in multiple stages.

In a Montreal home, this heating can supplement the heat pump under certain extreme conditions.

The setting is nevertheless crucial.

We want to avoid activating an energy-intensive electrical element unnecessarily while the heat pump can still efficiently provide the required heat.

Commissioning must therefore coordinate:

the outdoor temperature, the home's demand, the heat pump, and the auxiliary heating.

485 communication, 24 V thermostat, and renovation without opening all the walls

Thermostat wiring can be a significant constraint in a finished home.

Midea provides different control scenarios for the EVOX G3, including 485 communication as well as 24 V solutions with third-party thermostats, depending on the configuration.

With the Midea communicating system, the thermostat and SmartHome app can also enable scheduling, certain comfort settings, consumption monitoring, and several diagnostic functions.

In a residential area such as Rosemont–La Petite-Patrie, this flexibility can help avoid invasive work solely to redo the control wiring.

MERV 13 filtration: worthwhile, but only with enough surface area

EVOX G3 documentation indicates compatibility with 1-, 2-, or 4-inch filters, including MERV 13 options.

A higher level of filtration can reduce the amount of dust and particles circulating in the home.

However, the filter must be large enough to allow the required airflow to circulate.

A small, highly restrictive MERV 13 filter can significantly increase static pressure.

At AirGreen, we therefore prefer to assess filtration, return-air dimensions, and CFM simultaneously.

R-454B: a different generation from older central heat pumps

The EVOX G3 uses R-454B refrigerant, an A2L-class refrigerant.

Midea documentation indicates a global warming potential of 466 and confirms its use in the EVOX central range.

For homeowners, this transition does not change the everyday use of the heat pump.

For our technicians, however, it means that the installation, servicing, and handling of the refrigerant must follow procedures suited to A2L equipment.

And the LogisVert grant?

The Midea brochure indicates that the presented range exceeds the ENERGY STAR Most Efficient specifications applicable to the configurations described.

However, this brochure alone cannot confirm the exact eligibility or the amount of a LogisVert grant for this Rosemont–La Petite-Patrie installation.

To do this properly, it is necessary to identify the precise combination of the outdoor and indoor units and verify its official reference applicable to the program.

We therefore avoid calculating a subsidy based on the name “EVOX G3” or the appearance of the condenser.

The mistakes this compact installation helps us illustrate

A project like this makes it possible to highlight several useful principles before a central heat pump installation in Montréal:

1. Do not block the fan with a staircase or fence.
2. Do not install the unit directly in the snow or at ground level.
3. Preserve occupant pathways around the equipment.
4. Maintain genuine access to the technical panels.
5. Position the disconnect logically and accessibly.
6. Do not estimate capacity based on the condenser's size.
7. Check the ductwork before increasing the tonnage.
8. Do not confuse an ENERGY STAR designation with automatic confirmation of a subsidy.
9. Size the filtration according to the installation's actual airflow.

An AirGreen installation that uses the available space without sacrificing serviceability

This Rosemont–La Petite-Patrie project is a good example of an installation where discretion does not mean completely hiding the heat pump.

The better solution was instead to integrate it intelligently into an already complex area of the home.

The outdoor unit is raised against the foundation, its fan maintains a clear discharge path, the metal staircase remains functional, the disconnect is accessible, and the technical side can still be serviced.

This is the approach we apply at AirGreen for our central heat pump projects in Montréal, Laval, Longueuil, on the North Shore and South Shore.

The MIDEA EVOX G3 offers an interesting technical platform with its advertised operation down to -30 °C, inverter, compact outdoor design, modular indoor unit, advanced airflow control, and R-454B refrigerant.

But in a real home, these features are not enough.

The result also depends on the support, airflow, ductwork, CFM, static pressure, auxiliary heating settings, and the quality of the commissioning.

For this Rosemont–La Petite-Patrie installation, it is precisely the combination of all these details that makes it possible to integrate a modern central heat pump into a Montréal environment where every space matters.