Installation of a MIDEA EVOX G3 electric furnace in Sainte-Marthe-sur-le-Lac on Montreal’s North Shore

A horizontal MIDEA EVOX G3 installation in a space where the available height practically dictated the entire project

This MIDEA EVOX G3 installation MIDEA EVOX G3 electric furnace in Sainte-Marthe-sur-le-Lac illustrates a scenario completely different from a traditional central installation in the basement. Here, our AirGreen team had to integrate the indoor module into an extremely low technical space, above an interior opening, with very little clearance between the unit and the ceiling.

The job-site photograph immediately summarizes the challenge. The MIDEA EVOX G3 is not standing upright: it is installed horizontally, on an existing platform, practically parallel to the ceiling. At the right end, a large filter is directly accessible. Refrigerant lines run in front of the unit, while several flexible and metal ducts occupy the immediate surroundings. An opening in the ceiling finish also demonstrates the difficulty of accessing this technical area.

In this type of project, choosing a high-performance unit represents only part of the work. We must determine how to transport it, orient it, support it, connect the ductwork, keep the panels accessible, and plan for filter replacement without making every HVAC maintenance future unnecessarily complicated.

This is precisely the kind of situation for which the design of the MIDEA EVOX G3 becomes particularly worthwhile.

An EVOX G3 installed horizontally rather than vertically

In many homes in Montreal, Laval, Longueuil, the North Shore, and the South Shore, a central furnace is installed vertically in a mechanical room. Air enters from the bottom or side and exits toward the supply-air ductwork located above.

In Sainte-Marthe-sur-le-Lac, this configuration simply was not suitable for the available space.

We therefore worked with a horizontal configuration, allowing the system to occupy the length of the utility cavity rather than its height.

MIDEA documentation confirms that the EVOX G3 was specifically designed for multiple orientations. Its modular design Block N Lock allows six configurations, including vertical, downward, right-horizontal, and left-horizontal airflow, as well as different applications designed for height restrictions. The manufacturer also highlights how easy it is to handle its modules in difficult locations such as attics and basements.

This project clearly demonstrates the value of this flexibility: when a few dozen centimeters of height make the difference between a possible and impossible installation, the unit’s orientation becomes a major technical feature.

An installation area where every centimeter mattered

The photo reveals several simultaneous constraints.

The ceiling is immediately above the unit. Metal ducts already pass through this area. On the right side, several flexible ducts occupy the available space. In front of the unit, the insulated refrigerant line must reach the coil without being crushed or placing mechanical stress on the connections.

The unit also rests on a platform, with small support shims visible beneath the cabinet.

This kind ofHVAC installation in a restricted space requires particularly precise planning because we must preserve all of the following simultaneously:

• the clearance required for the unit;
• access to the panels;
• the space needed to replace the filter;
• the routing of the refrigerant lines;
• the transition to the existing ducts;
• cabinet stability;
• future access for diagnostics and maintenance.

An installation can be technically connected yet extremely difficult to service. We specifically aim to avoid this outcome.

The large filter visible in the photo is a central element of this configuration

One of the most striking details in the photograph is at the far right end of the system: the return filter is directly visible in its support.

Its location is not incidental.

In such a compact horizontal configuration, it must be possible to remove and replace the filter without moving the furnace, dismantling the ducts, or opening a large section of the ceiling.

We therefore pay particular attention to the direction in which the filter is removed and to the available clearance.

MIDEA indicates that the EVOX G3 range can be used with filtration modules compatible with filters measuring 1, 2, or 4 inches, including MERV 13 solutions. The manufacturer states that this filtration can help capture more dust, pollen, particles, and contaminants, particularly those from pets.

However, choosing a filter should never come down to selecting the highest MERV rating.

A filter must also allow enough air to pass through

A highly restrictive filter can increase the system’s static pressure if it does not provide enough surface area.

This can result in:

• insufficient airflow;
• a fan working harder;
• more noise;
• a change in how the coil operates;
• a decrease in comfort in certain rooms.

We therefore always view filtration as a component of the complete central system, and not as an independent accessory.

An existing duct network that dictates its geometry

The photograph clearly shows that the EVOX G3 had to be integrated into infrastructure that was already in place.

The ducts do not start with our new unit. They already run through the ceiling and connect to different parts of the house.

In a renovation, we cannot simply move these ducts arbitrarily to create a more symmetrical photograph. We need to understand their function, dimensions, and the airflow rates they must carry.

In particular, we check whether the new configuration can properly supply the air needed by the different zones without creating excessive static pressure.

Computational Constant Airflow 2.0 technology: particularly useful with existing ducts

MIDEA equips the EVOX G3 with its Computational Constant Airflow 2.0.

According to the manufacturer's documentation, this function adjusts the fan's power and speed to maintain airflow when the system resistance varies. Depending on the conditions presented, the EVOX G3 can operate at up to approximately 1.2 in. of external static pressure, with up to 60 airflow adjustment levels.

For an existing home in Sainte-Marthe-sur-le-Lac, this provides very useful adjustment flexibility during commissioning.

The actual network may include:

• different duct diameters;
• unequal lengths;
• several elbows;
• grilles with different resistance levels;
• a more or less restrictive filter.

The fan can better adapt to these variations.

However, this does not mean that poor duct design becomes acceptable. If we encounter a major restriction, we still need to correct it or account for it in the design.

The refrigeration lines also had to find their way through this very low space

The large white line visible in the foreground is an important part of the refrigeration circuit.

Its insulation limits heat exchange with the surrounding air and protects against condensation when it operates at low temperatures.

A smaller copper line also runs alongside it.

In a typical mechanical room, we sometimes have plenty of space to organize their routing. Here, we had to work around a platform, the unit, the air ducts, and a ceiling just a few centimeters away.

In particular, avoid:

Bends with radii that are too tight

A line must not be crushed simply to save a few centimeters.

Stress on the connections

The weight or position of the pipe must not continuously pull on the connection to the coil.

Panel obstruction

We must maintain access to the system components.

This attention is important both on the day of installation and ten years later during a diagnostic.

Why the MIDEA EVOX G3 is particularly well suited to a modern central heat pump on the North Shore

An “electric furnace” that operates with a central heat pump

In Quebec, the term electric furnace is frequently used to designate the indoor module of a central system comprising the blower, coil, and electric auxiliary heater.

Technically, MIDEA refers to this part of the EVOX G3 as a central air handler.

When paired with the corresponding outdoor heat pump, the heat pump normally provides most of the heating. The electric elements then provide supplemental heat depending on conditions, settings, and the home’s thermal load.

MIDEA offers a three-stage auxiliary heating kit capable of delivering up to 25 kW, including 10, 15, and 25 kW configurations. The manufacturer states that this auxiliary heater can be activated and adjusted progressively according to temperature changes.

The precise electrical power installed at this site cannot be confirmed from the photo provided. We therefore avoid arbitrarily assigning it a value.

Why we do not automatically choose the maximum electric resistance

A 25 kW kit available in the catalog does not mean that a home needs 25 kW.

The appropriate capacity depends in particular on:

• of the actual heat losses;
• of the heat pump’s capacity in cold weather;
• of the floor area;
• of the insulation;
• of the electrical panel;
• of the circuit supplying the furnace;
• of the control strategy.

A properly sized auxiliary heater complements the heat pump. Conversely, a system chosen without analysis can unnecessarily increase electrical demand.

Capacities ranging from approximately 18,000 to 54,000 BTU/h depending on the system

The EVOX G3 family includes different capacity combinations.

MIDEA’s technical table presents systems of 18,000, 24,000, 30,000, 36,000, 48,000, and 54,000 BTU/h, with different performance characteristics depending on the indoor-outdoor pairing.

The exact capacity of this installation at Sainte-Marthe-sur-le-Lac is not identifiable enough in the photograph for us to state a figure as certain.

This is important because a professional installation should never be sized based on the apparent size of the cabinet.

We instead use the building load, the characteristics of the duct network, and the available capacity at low temperatures.

Up to 19 SEER2 and 10.8 HSPF2 depending on the selected combination

The EVOX G3 documentation indicates performance of up to:

• 19 SEER2;
• 12.5 EER2;
• 10.8 HSPF2;
• a COP at 5°F (-15°C) of up to 2.14.

These values correspond to the best configurations in the product range and vary depending on the matched models.

That is why we encourage homeowners comparing two central heat pumps to check the exact model numbers.

Two contractors may both offer “MIDEA EVOX G3” while proposing combinations that do not have exactly the same performance.

Cold-weather performance suited to the climate of Sainte-Marthe-sur-le-Lac

Winter performance is obviously an important criterion on the Montreal's North Shore.

MIDEA indicates that its Extreme Heat platform can maintain continuous operation down to -30°C. The documentation also shows up to 100% heating capacity at -25°C, with a COP that can reach approximately 1,9 under the stated reference conditions.

This data changes how we must view a central heat pump.

We are no longer talking only about a unit intended to cool in summer and provide light heating in spring or fall. The system is designed to provide a significant portion of the heating even when outdoor temperatures become decidedly negative.

Auxiliary electric heating remains available when the building's demand requires it.

R-454B and a new generation of central systems

The documented EVOX G3 platform uses R-454B refrigerant.

MIDEA indicates a global warming potential for this A2L refrigerant of 466.

This change entails specific work methods during installation, troubleshooting, and service.

For us, this means using procedures and equipment suited to the installed refrigerant rather than treating a new system like an older R-410A unit.

Communicating control or 24 V thermostat, depending on the configuration

A renovation like this also involves another constraint: the existing wiring.

MIDEA provides several control options for the EVOX G3, including communicating control 485 and certain configurations using a traditional thermostat 24 V.

This flexibility can be particularly useful when the unit is installed in a similarly difficult-to-access location.

Completely rerouting a thermostat cable through finished walls or ceilings may require additional work. When the existing installation is compatible, some parts of the wiring can sometimes be retained.

Nevertheless, we always verify the number of conductors and the required functions before making this decision.

LogisVert: What a Sainte-Marthe-sur-le-Lac Homeowner Should Check

As of August 2026, Hydro-Québec indicates that a heat pump eligible for the program LogisVert may receive financial assistance of $50 per 1,000 BTU/h at -8°C when it is ENERGY STAR certified, or $120 per 1,000 BTU/h at -8°C when it is also rated ENERGY STAR – Cold Climate, provided that all program conditions are met.

Hydro-Québec also specifies that, for installations carried out since November 26, 2025, the complete system must meet the applicable criteria; for a central heat pump, this includes the indoor unit and the outdoor unit.

MIDEA documentation also presents the range as exceeding the ENERGY STAR Most Efficient specifications in the configurations concerned.

However, this does not allow us to automatically declare this specific installation eligible based solely on the photograph. To confirm the rebate, it is necessary to verify the exact indoor and outdoor models, as well as the recognized combination at the time of installation.

What this installation reminds us about horizontally installed equipment

Installing a furnace horizontally creates different priorities than a vertical installation.

We must pay particularly close attention to:

• the unit’s support;
• its level;
• the direction of airflow;
• access to the filter;
• the refrigerant line routing;
• access to the panels;
• the clearances from the ceiling;
• future maintenance work.

On this project, the accessibility of the filter visible at the end of the unit is particularly important. A filter that requires an hour of disassembly to replace will inevitably be serviced less often than a properly accessible filter.

An installation where the EVOX G3’s flexibility directly addressed the constraints of the house

This project in Sainte-Marthe-sur-le-Lac demonstrates very clearly why we never choose a central furnace solely based on its capacity or SEER2 rating.

The geometry of the house matters.

Here, the low ceiling and horizontal mechanical space determined the system’s orientation. The existing ductwork determined the connections. The available access influenced the filter’s positioning. The refrigerant line routing had to respect the panels and service connections.

The MIDEA EVOX G3, thanks to its multiposition and modular design, enabled us to adapt the system to this reality rather than trying to completely reshape the building around the unit.

At AirGreen, this is precisely how we approach a central HVAC installation : we look at the entire project, from the ductwork to the filter, from auxiliary heating to the refrigerant, and from the installation space to future maintenance.

We carry out this type of project in Sainte-Marthe-sur-le-Lac and throughout the North Shore, as well as Montreal, Laval, Longueuil, and the South Shore.

A good installation is not simply one that works when it is turned on. It is one that remains logical, accessible, and suited to the building several years after our team has left.