Installation of a MIDEA EVOX G3 electric furnace in Verdun, Montreal: central integration in an existing mechanical room

In Verdun, an HVAC modernization in which the new furnace had to adapt to the ducts, the available space, and the reality of the building

This installation carried out in Verdun, Montreal, shows a stage that is rarely seen once the work is complete: the MIDEA EVOX G3 electric furnace open during installation, with its accessible electronic and mechanical components, the new sheet-metal connections being integrated, and the existing duct network all around it.

For us, this photo is particularly representative of the real work behind a central system replacement. A new furnace never operates alone. It must integrate with a return-air network, a main supply, the ducts serving the different rooms, the thermostat, the electrical supply, and, when it is part of a central system with a heat pump, the refrigerant circuit connecting the indoor module to the outdoor unit.

In Verdun, where basements and mechanical rooms can have very different configurations from one property to another, this integration often requires more work than simply removing the old equipment.

On our worksite, the photo shows a particularly dense mechanical area: large galvanized ducts, custom transitions, limited space between the equipment, wiring being connected, and direct access to the control board and fan of the MIDEA EVOX G3. A front panel was removed to allow the work and remains temporarily in front of the unit. This is exactly the stage at which our technicians can check the connections, ventilation settings, and overall integration before the system is permanently closed.

Why this central replacement in Verdun required genuine ductwork adaptation

In new construction, the network can be designed around the dimensions of the new equipment. In an existing home, the opposite is true: we must make a new generation of HVAC system work with infrastructure that may have been in place for several decades.

A photo of our installation in Verdun shows several transitions made of galvanized sheet metal. They are not there for appearance. They serve to bring air from the existing network to the new unit and then redistribute the conditioned air through the home's ducts.

A poorly designed transition can create several problems:

• excessive turbulence;
• increase in static pressure;
• noise in the ducts;
• reduced airflow;
• temperature differences between rooms;
• unnecessary strain on the blower motor;
• actual performance lower than the system’s theoretical capabilities.

We therefore take the time to consider the entire system, particularly during a central electric furnace installation in Montreal.

The visible work on this Verdun installation also shows why the connections must be completed before considering the job finished. The upper ducts must be properly aligned with the unit’s outlet, the joints must be airtight, and the service components must remain accessible.

An indoor unit designed to facilitate the replacement of old furnaces

The MIDEA EVOX G3 has an interesting advantage in this type of project: its range was designed to fit more easily into spaces previously occupied by central furnaces.

MIDEA specifies cabinet widths of approximately 14.5 to 21.5 inches, depending on capacity. The platform can also recognize different electrical supplies, including 115 V or 208/230 V depending on the configuration.

This detail is particularly relevant in areas such as Verdun, LaSalle, Montreal, Laval, Longueuil, the North Shore, and the South Shore, where we encounter a mix of older homes, duplexes, plexes, renovations, and buildings in which mechanical rooms were not necessarily designed for contemporary central systems.

In a constrained space, a few inches can determine:

• if the unit can fit through the staircase;
• if it can be installed without moving a wall;
• if the front panel will remain accessible;
• if we can fabricate a reasonable duct transition;
• if the refrigerant connections can be serviced later.

The EVOX G3 modular design makes perfect sense in a Montreal basement

MIDEA uses a modular design called Block N Lock. According to the manufacturer’s documentation, the unit can be reconfigured for several orientations: upflow, downflow, right horizontal, left horizontal, as well as “low-boy” arrangements for particular height constraints.

It is not simply a convenient feature in a brochure.

During our installations, this modularity can facilitate transporting and integrating the unit into:

• a narrow basement staircase;
• a mechanical room located behind several pieces of equipment;
• a room where the available height is limited;
• a location where the supply and return ducts do not match a conventional vertical configuration.

On the Verdun job site shown here, the proximity of the large ducts and other mechanical components clearly shows why the cabinet’s physical flexibility can become important.

Behind the panel: what we actually see inside this MIDEA electric furnace

Removing the panel gives us a direct view of the inside of the unit.

In the upper section, we can see the control circuit board, several connections, and the components that control system operation. Lower down, we can see the blower assembly that moves air through the ducts.

In an older furnace with a relatively simple blower, airflow could be much less adaptable. With a platform like the EVOX G3, blower management is an integral part of efficiency and comfort.

This means we do not simply “set the blower to one speed” and leave the job site. Commissioning involves considering the required airflow and the actual resistance of the ductwork.

Computational Constant Airflow 2.0 technology: an important advantage in existing homes

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

The principle is particularly relevant during a replacement: the blower can adjust its output to maintain the requested airflow despite variations in resistance throughout the ductwork and filtration system.

MIDEA indicates a capacity of up to approximately 1.2 in. of external static pressure, as well as an airflow adjustment range including up to 60 levels.

In practice, this capability helps us fine-tune an installation to suit the home.

Let’s consider two buildings equipped with units of comparable capacity. One may have large, relatively short ducts. The other may have several long branches, more elbows, and a more restrictive filter. The two installations therefore do not have the same airflow conditions.

What this technology should never be used to conceal

A blower capable of adapting to higher pressure does not justify neglecting the ductwork.

If an air return is much too small or a main duct creates a major restriction, we need to address the mechanical issue rather than asking the motor to compensate continuously.

At AirGreen, we therefore consider airflow control a precise adjustment tool, not a way to bypass sound HVAC design practices.

Efficiency, winter heating, filtration, and controls: what you need to know before choosing an EVOX G3

A central lineup reaching up to 19 SEER2

The EVOX G3 lineup presented by MIDEA includes several capacities. The technical specifications indicate systems ranging from 18,000 to 54,000 BTU/h depending on the combination, with efficiencies of up to 19 SEER2, 12.5 EER2, and 10.8 HSPF2.

The manufacturer's performance table presents various configurations of 18,000, 24,000, 30,000, 36,000, 48,000, and 54,000 BTU. Performance varies according to the selected indoor/outdoor combination.

The photo of our Verdun job site Verdun does not allow the exact model of the unit to be read clearly enough to assign a precise capacity to this installation with certainty. We therefore prefer not to arbitrarily state a tonnage.

For us, this is an important rule: the series name never replaces the exact model number.

Sizing should not be based solely on floor area

A homeowner can easily be told that a certain area automatically requires two, three, or four tons.

In reality, several factors influence the choice:

• living area;
• insulation;
• air infiltration;
• number and type of windows;
• solar exposure;
• number of floors;
• room distribution;
• ductwork dimensions;
• available airflow;
• the building's heat loss.

A larger unit does not automatically provide better comfort. An oversized system may run in shorter cycles, be less efficient at summer dehumidification, and create more pronounced temperature variations.

A cold-climate EVOX G3 central heat pump

When the EVOX G3 electric furnace is paired with the compatible heat pump from the same platform, the system is designed to operate in demanding winter conditions.

MIDEA documentation indicates continuous operation down to -30 °C. For the three-ton system used in the tests mentioned by the manufacturer, the data also show heating capacity reaching 100% at -25 °C, with a COP of up to approximately 1.9 under the published conditions.

This type of performance is particularly important for a system installed in Verdun or elsewhere in Greater Montreal, where a heat pump must not only be efficient at +8 °C or 0 °C: it must continue to make a meaningful contribution to heating when winter becomes much colder.

Auxiliary electric heating: up to 25 kW depending on the configuration

The EVOX G3 platform also provides for the addition of an auxiliary electric heating kit of three stages, with capacities of up to 25 kW. MIDEA indicates that this auxiliary heat can be activated and adjusted according to temperature changes.

However, it would be incorrect to conclude that a home should automatically receive the largest available unit.

We need to check:

• the required heating capacity;
• heat pump performance at low temperatures;
• the electrical panel capacity;
• the maximum allowable current;
• the conductor gauge;
• the required circuit breaker;
• the auxiliary heating control strategy.

In some buildings, electrical sizing becomes just as important a part of the project as thermal sizing.

R-454B: a new generation of A2L refrigerant

The EVOX G3 range documentation indicates the use of R-454B refrigerant, whose global warming potential announced by MIDEA is 466.

The safety label visible on the panel removed in our photo from Verdun also reminds us that we are working with a generation of equipment using an A2L-classified refrigerant.

This involves appropriate installation and service methods.

When replacing an old R-410A system, we therefore do not treat the project as a simple equipment swap. The procedures, tools, and requirements associated with the refrigerant must be followed.

Filtration up to MERV 13, but always with attention to airflow

MIDEA indicates that the EVOX filtration module can accommodate filters of 1, 2, or 4 inches, with advertised compatibility up to MERV 13.

A MERV 13 filter may be useful for better capturing certain dust, particles, pollen, and pet hair. However, we must always consider the pressure drop it adds to the system.

The best filter for an installation is therefore not necessarily the one with the highest MERV rating. The goal is to find the right balance between:

• filtration;
• filtering surface;
• resistance;
• airflow;
• fan capacity.

This verification is part of a well-designed central installation.

Communicating control or 24 V thermostat

The EVOX G3 platform can operate with different control strategies. MIDEA specifically indicates compatibility with 24 V communication 485 or a control 24 V, with automatic mode identification.

This can facilitate certain replacement projects, especially when thermostat wiring already exists in the walls.

With the MIDEA communicating thermostat and the SmartHome app, the documentation also provides for managing schedules, temperature, and humidity, as well as monitoring certain consumption data and diagnostic functions.

Rebates: the EVOX G3 name alone is not enough

When a homeowner is looking for a central heat pump eligible for a rebate in Quebec, it is essential not to rely solely on the brand or series.

Eligibility must be verified based on the exact combination consisting of:

• the outdoor unit;
• the indoor unit;
• capacity;
• the applicable certification reference;
• certified performance ratings;
• the program conditions in effect at the time of the project.

We therefore carry out this verification before associating a specific financial assistance amount with an installation.

What the Verdun photo reveals about the quality of a central system installation

A job-site photograph taken with the panels removed can sometimes be more informative than a perfectly clean final photo.

Here, we can see the actual integration.

We can see the duct transitions fabricated on site, access to the control board, the fan, the connections, the available space around the unit and the constraints specific to the basement.

This also highlights several principles we apply to our installations:

Preserve service access

A technician must be able to remove the panels and service the main components without having to demolish the ductwork.

Make properly sized sheet-metal transitions

The new cabinet and the existing ductwork do not always have the same dimensions. The transition must guide the air rather than restrict it.

Do not complete the adjustments before the system is ready

The airflow and fan settings must be adjusted once the final configuration of the ductwork, filter and dampers is known.

Check the complete system, not just the furnace

An excellent indoor unit cannot reach its full potential with poor return air, inadequate ductwork or improper settings.

A Verdun installation that demonstrates the true role of an HVAC contractor

This MIDEA EVOX G3 electric furnace installation in Verdun is not simply a matter of placing a new machine in a basement.

Our work involves connecting several elements: the indoor unit, central heat pump, duct network, airflow, filtration, controls and electrical supply.

The job-site photo shows precisely this intermediate stage, when everything is accessible and verifiable before the panels are closed and finishing work begins.

This is also where our experience becomes important. Two homes can receive the same equipment model and deliver very different results if the ductwork, settings or sizing are not handled with the same level of rigor.

At AirGreen, we apply this approach to our heating, air conditioning, central heat pumps and electric furnaces to Verdun, Montreal, Laval, Longueuil, the North Shore and the South Shore.

An EVOX G3 provides a modern, adaptable central system capable of operating in harsh winter conditions. Our role is to ensure that this technology is properly integrated into the home where it is installed.