Installation of a MIDEA EVOX G3 electric furnace in a low-boy configuration in Saint-Lambert, Montreal’s South Shore

In Saint-Lambert, the available space led us to use one of the most interesting configurations of the MIDEA EVOX G3

This MIDEA EVOX G3 electric furnace installation in Saint-Lambert is an excellent example of a project where the quality of the result depends much less on a “standard” installation than on the ability to adapt the equipment to the existing building.

The job-site photo shows a compact mechanical room on Montreal’s Montreal’s South Shore, with a water heater installed immediately to the left, a central duct network already in place above the equipment, and relatively little available height. In this situation, installing a long conventional vertical air handler would have required more modifications to the duct network.

We therefore used the modular design of the MIDEA EVOX G3 configuration for installing its two main sections side-by-side, a low-boy particularly well suited to locations where height is the dominant constraint.

The result visible in the photo is very different from the usual appearance of a central furnace: the main module is installed on the left, while the section containing the coil is positioned on the right. Both work together as a single central HVAC system.

This possibility is not a job-site improvisation. MIDEA officially presents the EVOX G3 as a “Block N Lock” modular-design unit that can be configured in six ways, including upflow, downflow, left horizontal, right horizontal, and arrangements low-boy with top return and supply.

A side-by-side configuration that solves a height problem

In many residences in Saint-Lambert, particularly in basements where several mechanical systems share the same area, the available clear height can become more important than the floor area.

Several elements had to coexist on this project:

• the MIDEA EVOX G3 electric furnace;
• the existing central duct network;
• the refrigerant lines;
• the drainage system;
• a water heater installed in the immediate vicinity;
• the access required for maintenance;
• the electrical and control connections.

One of the main advantages of the EVOX G3 design is that we can separate and reposition the modules instead of being forced to keep a single very tall column.

In the photo, the left section uses a large sheet-metal transition to connect to the upper ducts. The right section is lower and has its own connection to the ductwork. Beneath both units, the base and connections are adapted to maintain the necessary airflow path between the sections.

This arrangement makes it possible to use more of the room's width while avoiding insufficient ceiling height.

Why the two cabinets do not represent two different systems

For a homeowner viewing this installation without knowing the EVOX G3 architecture, it would be easy to think that we installed two independent units.

That is not the case.

The module on the left contains the components related to moving and controlling the air. The module on the right can be identified by its copper refrigerant connections, its insulated lines, and especially its condensate drainage system. It forms the coil section that exchanges heat with the home's air.

Together, these two elements form the indoor unit of the central system.

This modular design also offers an advantage when transporting the equipment into a basement. MIDEA indicates that the system can be disassembled and reconfigured more easily to facilitate handling in places such as basements and attics.

The visible drainage on this installation deserves particular attention

One of the most interesting technical details in the Saint-Lambert photo is located to the right of the EVOX G3.

We can clearly see the white condensate drain pipe connected to the module containing the coil. The drain includes, among other things, a visible U-shaped trap, as well as access points fitted with red caps.

This detail may seem minor. However, it is essential to a properly installed central heat pump.

In cooling mode, the indoor coil becomes cold. Moisture in the air condenses on its surface and must be drained in a controlled manner.

The drainage network must therefore allow for:

• reliable water drainage;
• maintaining the proper pressure in the drain pan;
• access to the trap;
• periodic cleaning;
• unclogging without significant disassembly;
• an adequate slope to the drainage point.

Why provide cleaning access points?

Over the years, a condensate drain can accumulate dust, deposits, or biofilm.

When an installation has no practical access, a simple cleaning can become much more complicated than necessary.

On this project, the red caps visible near the trap make the system much more accessible. This is exactly the kind of detail we aim to plan for during an HVAC installationbecause a system should remain easy to maintain long after we are gone.

A flexible connector to limit vibration transmission

Another interesting element appears directly above the main module.

Between two sheet-metal sections, we can distinguish a black flexible connector.

In a central system, vibrations produced by a fan can be transmitted to the metal structure of the ducts. Depending on the installation’s geometry, this vibration can then become audible elsewhere in the home.

Integrating a flexible section between certain components of the ductwork helps reduce this mechanical transmission.

This is particularly relevant for a system that operates for long periods at low speed. Acoustic comfort does not depend solely on the number of decibels listed in a technical specification: the way the machine is connected to the building also plays a role.

An electric furnace designed to work with an inverter heat pump

In Quebec, we naturally use the expression electric furnace to refer to the indoor unit of a forced-air central system.

In the case of the EVOX G3, it is more precisely an air handler intended to be paired with a inverter central heat pump.

The system can also receive auxiliary electric heating.

MIDEA provides a three-stage auxiliary heating kit that can reach 25 kW, depending on the selected configuration. The documentation indicates that these stages make it possible to adapt the heat output to temperature variations rather than operating solely according to an all-or-nothing, full-power logic.

At AirGreen, however, we never select a 25 kW element simply because it represents the maximum available.

Instead, we consider:

• the building’s heat loss;
• the heat pump’s low-temperature capacity;
• the available airflow;
• the electrical panel capacity;
• the conductor gauge;
• stage sequencing;
• the thermostat control strategy.

Dimensions designed to facilitate replacements

Page 5 of the MIDEA documentation also highlights a highly relevant feature for renovation projects: depending on the capacity, EVOX G3 cabinets use widths of approximately 14.5 to 21.5 inches, to facilitate their integration in place of many existing central systems. The indoor units in question are also designed to handle different supply voltages specified by the manufacturer.

This compactness does not eliminate the need to fabricate transitions.

However, it can reduce the amount of modification required around the equipment, which is particularly useful when the installation is only a few inches away from a water heater, a wall, or another piece of mechanical equipment.

Airflow remains the priority, even with a highly advanced unit

A central system does not heat a house simply because its compressor produces heat. That energy must be transported to the different rooms.

This is the role of the ductwork.

The EVOX G3 features the technology Computational Constant Airflow 2.0, developed to automatically adjust fan power when system resistance changes.

According to MIDEA documentation, this technology can manage static pressure of up to 1.2 in. of water column under the specified conditions and offers up to 60 airflow adjustment levels.

For an installation like the one in Saint-Lambert, this capability is particularly useful because we are integrating the new equipment into a system that existed before the heat pump.

However, this does not authorize us to neglect the ductwork.

Excessive static pressure can be caused by:

• an undersized return-air duct;
• a filter that is too restrictive;
• a crushed duct;
• abrupt transitions;
• several closely spaced elbows;
• improperly adjusted dampers.

The constant airflow technology is there to stabilize system operation, not to replace proper ductwork design.

An EVOX G3 suited to Quebec's climate, but whose exact performance always depends on the installed combination

Several capacities available in the range

The MIDEA technical data sheet presents various EVOX G3 combinations ranging from approximately 18,000 to 54,000 BTU/h.

Depending on the models, the published values reach up to:

• 19 SEER2;
• 12.5 EER2;
• 10.8 HSPF2;
• a COP of up to 2.14 at -15 °C depending on the combination presented.

Page 11 of the brochure details capacities of 18,000, 24,000, 30,000, 36,000, 48,000, and 54,000 BTU/h, with different efficiencies for each.

However, the nameplate visible in our Saint-Lambert photo is not clear enough for us to publish a precise tonnage without risking an error.

This is an important distinction.

A furnace with a similar cabinet can be paired with several capacities. We therefore always identify the system by the indoor model, outdoor model, and exact AHRI combination.

Heating operation down to -30 °C

The EVOX G3 Extreme Heat platform is advertised by MIDEA for continuous operation down to -30 °C.

The documentation also cites tests on a three-ton MIDEA system with capacity reaching 100% at around -25 °C and a COP of approximately 1.9 under the conditions presented by the manufacturer.

For a residence Saint-Lambert, this ability to continue operating in extreme cold is much more relevant than a simple seasonal efficiency obtained under moderate conditions.

However, a common confusion must be avoided: “operates down to -30 °C” does not automatically mean “provides its full rated capacity down to -30 °C.”

Each combination has its own performance curve.

That is why we assess the available capacity as the temperature drops and then determine the amount of auxiliary heating required.

R-454B and the new A2L systems

The photo shows an A2L safety label on the MIDEA, and the EVOX G3 lineup does indeed use R-454B refrigerant.

The manufacturer's documentation indicates a global warming potential, or GWP, of 466 for this refrigerant.

This transition to R-454B is important for the HVAC industry.

Daily use for the homeowner remains very similar, but installation requires practices adapted to A2L refrigerants, particularly for:

• tools;
• leak testing;
• evacuation;
• connections;
• commissioning;
• refrigerant handling.

Filtration must be selected according to the actual airflow

MIDEA also offers a filtration module compatible with filters measuring 1, 2, or 4 inches, including MERV 13 in the intended applications.

A MERV 13 filter can capture more fine particles, but that does not mean it should be added without checking the ductwork.

The filter creates resistance.

We must therefore consider all of the following simultaneously:

• of its surface area;
• of its thickness;
• of its condition;
• of the required airflow;
• of the total static pressure.

This check is particularly important for a inverter central heat pump, where stable airflow directly contributes to proper heat transfer.

An installation designed with the technician who will return a few years from now in mind as well

The Saint-Lambert photo shows a compact installation, but the service points remain accessible.

The condensate trap is in front of us. The cleaning plugs are easy to reach. The refrigerant connections for the right-hand module remain visible. The fronts of both sections can be opened without having to remove the adjacent water heater.

This accessibility is important for theHVAC maintenance.

A machine can operate for years, but certain components will eventually require:

• a cleaning;
• an inspection;
• an electrical check;
• a static pressure measurement;
• an intervention on the drainage system;
• an electronic diagnostic.

An installation that leaves no room for the technician unnecessarily increases the time and complexity of future service work.

LogisVert: eligibility must be verified for the exact combination

For a central heat pump installed in Quebec, the financial assistance Hydro-Québec’s LogisVert may represent a significant amount.

As of August 2026, Hydro-Québec indicates assistance of $50 per 1,000 BTU/h at -8 °C for an eligible ENERGY STAR-certified heat pump, or $120 per 1,000 BTU/h at -8 °C when it is also rated ENERGY STAR “cold climate,” subject to compliance with all program conditions.

For heat pumps installed since November 26, 2025, certification ENERGY STAR is part of the eligibility requirements.

It is therefore impossible to announce the exact subsidy amount based solely on the words MIDEA EVOX G3.

For an installation in Saint-Lambert, we must verify:

1. the exact indoor unit model;
2. the exact outdoor unit model;
3. the certified combination;
4. the AHRI number;
5. the recognized capacity at -8 °C;
6. the applicable ENERGY STAR rating;
7. the LogisVert conditions in effect on the installation date.

The MIDEA brochure documents the performance of the product line, but it alone does not confirm eligibility for the Quebec program.

This Saint-Lambert project shows what it really means to “adapt” a central system

This installation includes several interesting technical elements, but the most important thing remains how they work together.

Here we have a MIDEA EVOX G3 in a modular low-boy configuration, installed side by side to comply with a height constraint. We adapted the sheet-metal transitions, connected the system to the existing central network, installed the refrigerant lines, provided a condensate drain with an accessible trap, and used a flexible connector in the ductwork.

All of this had to fit into a mechanical area already occupied by a water heater and existing infrastructure.

This is precisely the approach we apply at AirGreen in our installations of electric furnaces and central heat pumps in Saint-Lambert, Longueuil, Montreal, Laval, on the North Shore and South Shore.

We are not simply looking for a place to set down the new equipment.

We want to understand:

• how air returns to the unit;
• how it passes through the coil;
• how it returns to the ductwork;
• how condensate water will be drained;
• how vibrations will be controlled;
• how the system will be serviced;
• how the heat pump and auxiliary heating will work together on the coldest days.

In this Saint-Lambert project, the side-by-side configuration is therefore much more than an aesthetic feature. It demonstrates one of the most tangible advantages of the design MIDEA EVOX G3 to allow the installation to adapt to the building, rather than forcing the building to adapt to a single furnace configuration.