An installation in Bethany that reveals what is rarely seen: the inside of the MIDEA EVOX G3 during commissioning
During this MIDEA EVOX G3 electric furnace installation in Bethany, we photographed the system at a particularly interesting stage of the project: the upper panel has been removed, and the inside of the unit remains fully accessible for inspections, connections, and final configuration.
This view helps explain that a central HVAC installation does not simply involve placing a new metal cabinet where the old one stood. Behind the panels of the EVOX G3 are the fan, control electronics, wiring, electrical components, and all the interfaces required for the heat pump, auxiliary heating, and the home’s ductwork to operate properly.
In the photo taken in Bethany, several elements immediately draw our attention. The new MIDEA is installed vertically on a metal base. Above it, a custom transition connects to the existing ductwork. In the open upper section, we can clearly see the control circuit board, the electrical terminal blocks, and especially the large ventilation assembly that circulates air throughout the residence.
To the right of the system, there is also an existing Honeywell humidifier mounted on the ductwork. This proximity adds a constraint typical of central system replacements: the new equipment must be integrated into a mechanical environment that already has its accessories, ductwork, clearances, and history.
The large fan visible in the photo is one of the most important components of the entire system
The cylindrical component visible in the center of the open section is the indoor unit’s ventilation assembly.
Its job seems simple: move air.
In reality, its role is critical to almost all of the system’s performance.
The fan must provide enough air to:
- distribute heating evenly throughout the rooms;
- ensure effective air conditioning in summer;
- allow the cooling coil to exchange heat properly;
- operate with the installed filtration;
- maintain an acceptable noise level;
- limit temperature differences between the various areas of the house.
That is why we pay so much attention to airflow when commissioning an electric furnace or a central heat pump.
The EVOX G3 uses Computational Constant Airflow 2.0 technology. MIDEA explains that the fan adjusts its power and speed according to the conditions encountered in the duct system and at the filtration level. The documentation presents examples at 1,200 CFM with static pressure reaching up to 1.2 in. of water column.
The manufacturer also provides up to 60 air-volume adjustment levels, allowing much more precise configuration than simply choosing among a few fixed speeds.
Why we fully open the unit before considering the job complete
The photograph from Béthanie shows the MIDEA EVOX G3 without its upper panel. This is obviously not its final configuration.
This step gives us access to the components that must be inspected before the unit is permanently closed.
In particular, we can check:
- the quality of the electrical connections;
- control terminals;
- fan configuration;
- settings related to auxiliary heating;
- communications with the system controls;
- the equipment’s behavior during testing;
- the absence of abnormalities before the panels are replaced.
We can also directly inspect the fan and ensure that nothing is obstructing its operation.
A modern central system contains much more electronics than an old electric furnace with a single motor and a few relays. This sophistication provides greater control, but it also makes professional commissioning even more important.
A modular design that is particularly useful for renovations
The MIDEA EVOX G3 is not designed as a completely monolithic cabinet.
MIDEA uses an architecture called Block N Lock, allowing multiple installation configurations. The manufacturer's documentation shows six possible orientations, including upflow, downflow, right horizontal, left horizontal, and low-boy installations. The concept is intended in particular for basements, attics, and spaces where handling a traditional unit can become difficult.
At our Béthanie job site, we used a classic vertical configuration, but this modularity remains very useful during installation and servicing.
The junction between the unit’s sections is also clearly visible in the photograph.
This design offers a practical advantage: when we need to install a new central electric furnace in an existing home, we have more options for working around the height, width, stairs, and existing ducts.
The upper metal transition is just as important as the furnace itself
Above the unit, we can see a sheet metal transition connecting to the home's duct network.
This part of the installation is made to ensure a consistent connection between the opening of the new unit and the dimensions of the existing ducts.
A poor transition can lead to:
- an increase in static pressure;
- more turbulence;
- air noise;
- poor airflow distribution;
- additional work for the fan.
That is why sheet metal work should never be considered merely an aesthetic element.
A heat pump with excellent SEER2 and HSPF2 ratings can lose part of its practical advantage if air has to pass through an unsuitable network.
The flexible connection visible above the MIDEA also plays a role
Between certain metal sections above the unit, a flexible connection can be seen.
This type of connection helps limit the direct transmission of certain equipment vibrations to the duct network.
The desired result is not limited to a comfortable temperature. We also want to prevent mechanical vibration from being amplified by several metres of sheet metal throughout the house.
This is a good example of a subtle detail that can influence the perceived quality of a central heating installation.
A Honeywell humidifier already present beside the new system
The photograph also shows a Honeywell humidifier installed on the adjacent duct.
In homes equipped with a central forced-air system, a humidifier can be integrated into the network to manage humidity during the heating season.
When replacing a furnace, it is important not to treat this type of accessory as a completely independent element.
In particular, we need to check its placement, access, and how it fits with the new duct configuration.
In this Bethany installation, the space between the MIDEA EVOX G3, the ducts, and the existing humidifier therefore had to be taken into account from the planning stage.
The lower section: coil, refrigerant, and central heating
The lower section of the MIDEA visible in the photo includes the connections associated with the refrigeration circuit.
This highlights an important point: even though we are talking about a MIDEA EVOX G3 electric furnace, this indoor unit may be part of a true central heat pump system.
The outdoor heat pump then provides most of the heating when conditions permit, while the indoor unit handles the heat exchange and distributes the air through the ducts.
The EVOX G3 product line uses R-454B refrigerant, which belongs to the A2L category. MIDEA states that this refrigerant has a global warming potential of 466.
The A2L pictogram is also visible on equipment from this generation.
For us, this means using methods and tools adapted to this new category of refrigerants during installation and servicing.
An electric furnace designed to work with a heat pump through the harshest Quebec cold
In Béthanie, winter heating performance is obviously much more important than a simple cooling-efficiency figure.
MIDEA documentation states that the EVOX product line can operate continuously down to -30°C. For the 3-ton system used in some of the manufacturer's test data, MIDEA also reports particularly high heating capacity at very low temperatures, with values reaching up to 100% at -25°C under the stated conditions.
This does not mean that all EVOX G3 combinations produce exactly the same capacity at every temperature. To determine the precise performance of an installation, always use the exact indoor and outdoor model numbers.
From 18,000 to 54,000 BTU/h in the EVOX G3 product line
The documentation provided by MIDEA presents several central system capacities.
The technical table includes, among others, nominal configurations of:
- 18,000 BTU/h;
- 24,000 BTU/h;
- 30,000 BTU/h;
- 36,000 BTU/h;
- 48,000 BTU/h;
- 54,000 BTU/h.
Depending on the combination, heating capacities may differ slightly from the nominal cooling capacity.
The photograph of our installation in Béthanie does not allow us to identify the complete model with sufficient certainty to assign an exact tonnage to this unit. We therefore prefer to maintain this accuracy rather than arbitrarily stating a capacity.
For a homeowner comparing quotes, this is also an important point to remember: the cabinet alone does not make it possible to correctly identify the performance of a central heat pump.
Up to 19 SEER2 and 10.8 HSPF2, depending on the combination
For the entire product family presented in the brochure, MIDEA states that performance can reach:
- 19 SEER2;
- 12.5 EER2;
- 10.8 HSPF2;
- a COP of up to 2.14 at 5°F, or approximately -15°C.
These maximum values apply to the product line and must always be associated with a specific combination before being used in a quote or comparison.
At AirGreen, we specifically avoid presenting the best available figure for an entire product family as though it automatically applied to every installation.
Electric auxiliary heating: up to 25 kW depending on the configuration
The EVOX G3 can accommodate electric auxiliary heating.
MIDEA offers configurations of 10 kW, 15 kW, and up to 25 kW, with a multistage assembly that allows electric heating use to be adapted to the system’s needs.
The sizing of this backup system should never be improvised.
We must take into account:
- the heat pump’s capacity;
- the home’s heat losses;
- electrical panel;
- wiring gauge;
- airflow;
- backup requirements during extreme conditions.
Systematically installing the largest available component can create unnecessary electrical load and does not guarantee better operation.
Why the ECM blower visible in our photo deserves so much attention
The large ventilation assembly photographed in Bethany provides an excellent opportunity to explain the difference between a machine’s rated capacity and its actual operation.
Let’s take a simple example: if a heat pump must transfer a specific amount of heat through the coil, but the duct system does not provide sufficient airflow, system performance will be affected.
Conversely, excessive airflow can increase noise and alter comfort at the grilles.
We therefore need to achieve a balance.
MIDEA’s constant-airflow technology can help compensate for certain duct-system variations, but we must always check:
- static pressure;
- the return-air dimensions;
- the supply-air dimensions;
- the filter condition;
- the transitions;
- the dampers;
- the grilles.
That is precisely why we make adjustments with the panels open before returning the equipment to its final configuration.
1-, 2-, or 4-inch filter: beware of resistance
The EVOX G3 documentation provides for 1-inch, 2-inch, and 4-inch filters, including MERV 13-compatible configurations. MIDEA indicates that these options can capture more dust, pollen, particles, and pet hair or dander.
A more efficient filter may be worthwhile, but only if the duct system can provide the required airflow at that resistance level.
We therefore do not simply recommend “the highest MERV rating.”
The right filtration combines air quality, sufficient surface area, and acceptable static pressure.
Communicating controls or 24 V thermostat
The electronic board visible in the upper part of our installation also plays a role in the EVOX G3’s control flexibility.
According to MIDEA, the equipment can operate using 485 communication or, in certain configurations, with a conventional third-party 24 V thermostat. The manufacturer also provides various options for combining EVOX components with certain third-party equipment.
In a renovation, this flexibility can avoid additional work when existing wiring can be retained in an appropriate configuration.
The key, however, remains choosing the control method that truly allows the installed system to deliver the desired functions.
Mistakes to avoid when replacing a central furnace
This installation in Béthanie helps summarize several mistakes we want to avoid on our job sites:
- ordering the furnace before accurately measuring the space;
- relying solely on the tonnage of the old system;
- ignoring the static pressure of the ductwork;
- installing a transition that is too restrictive;
- choosing a filter without checking its impact on airflow;
- installing the largest available electric resistance heater by default;
- forgetting about access to the service panels;
- neglecting existing accessories, such as the humidifier;
- closing up the equipment without performing a complete commissioning;
- announcing performance or a rebate without confirming the exact models.
A central installation involves many variables that are not visible on a heat pump’s price sheet.
What this photo really shows about AirGreen’s work
Once the panels are put back in place, the MIDEA EVOX G3 regains the very understated appearance of a gray central cabinet.
But the photo taken during our Béthanie installation shows what lies behind this façade: a high-capacity blower, electronics, electrical connections, a modular architecture, and a set of components that must be configured to work with the home.
That is where professional installation becomes especially important.
At AirGreen, when we install a electric furnace, central heat pump, or ducted HVAC system, we do not look only at the equipment. We consider the entire system: air distribution network, filtration, airflow, static pressure, auxiliary heating, controls, existing accessories, drainage, and service access.
This method applies to our projects in Béthanie as well as those in Montréal, Laval, Longueuil, the North Shore, and the South Shore.
EVOX G3 technology offers us great flexibility, but it is the way it is integrated, adjusted, and verified on-site that transforms its technical specifications into real comfort in the home.