Installation of a MIDEA EVOX G3 central heat pump in Saint-Chrysostome, in Montérégie
In Saint-Chrysostome, AirGreen installs a MIDEA EVOX G3 central heat pump on wall brackets: heating down to -30 °C, R-454B, inverter, central ductwork, and LogisVert eligibility explained in detail.
In summer, the outdoor unit rejects the house's heat outside.
Generic illustration of this type of installation, not a survey of this job site. Tap a number.
It captures or rejects heat outside. It sits on a level base, above the snow, with free space all around.
The insulated refrigerant lines enter the house through a sealed opening and run to the indoor coil.
A shut-off switch near the outdoor unit isolates it safely for service.
Sitting on the indoor module, it moves heat between the house air and the refrigerant.
Electric furnace or air handler: its fan pushes air through the ducts. The electric backup takes over in extreme cold.
Supply ducts bring air to the rooms; returns bring it back to the unit. Their condition matters as much as the unit's.
It protects the coil and the fan. A dirty filter cuts airflow, so it gets checked regularly.
It runs the heat pump and the backup heat. It must be compatible with the installed system.
A central installation designed for Quebec winters, right down to the positioning of the outdoor unit
In Saint-Chrysostome, this MIDEA EVOX G3 central heat pump installation completed by AirGreen clearly shows that a successful HVAC project depends on more than simply choosing a high-performance unit. The outdoor location, height above the ground, access for maintenance, fan clearance, refrigerant line routing, and compatibility with the indoor air distribution system all have a direct impact on the final result.
The jobsite photo provides several interesting clues. Here we have a MIDEA outdoor unit with horizontal discharge, installed on metal wall brackets at foundation level. The area beneath the heat pump remains completely clear. A basement window is nearby, but the unit is positioned so that it does not obstruct the opening. The large front fan also has clear space to discharge air.
This type of configuration is particularly well suited to the conditions in Saint-Chrysostome and Montérégie, where a central heat pump must operate not only during periods of summer heat, but also during winter periods when snow, ice, and temperatures well below freezing are normal operating conditions.
Why install the MIDEA EVOX G3 on wall brackets?
A relatively simple detail in the photo summarizes much of our approach: the heat pump does not rest directly on the ground.
We used metal brackets secured to the foundation, which provides substantial clearance beneath the unit. This choice is particularly relevant during heating operation.
When a heat pump operates in winter, its outdoor heat exchanger can accumulate frost. The system must periodically run a defrost cycle. The resulting water must then be able to drain beneath the unit without gradually forming a block of ice against its frame.
Installing the unit too close to the ground can cause several problems:
- snow accumulation in front of or beneath the heat exchanger;
- ice formation beneath the unit;
- restricted airflow;
- more difficult access for a technician;
- more frequent contact with leaves, soil, and debris;
- more difficult winter maintenance after a heavy snowfall.
In Saint-Chrysostome, where winter conditions are a reality of the system's year-round operation, this additional height is therefore not decorative. It directly contributes to an installation better suited to the local climate.
An installation that also respects the basement window
At this site, we had to work around a basement window located immediately to the right of the heat pump.
This type of constraint is common in renovations. Relatively bulky equipment must be installed on a facade that already has windows, downspouts, electrical outlets, exhaust ducts, meters, or other architectural features.
We always try to avoid positioning a heat pump in a way that would:
- unnecessarily hide a window;
- complicate its opening;
- block access to a building component;
- make cleaning the unit almost impossible;
- force air recirculation against an obstacle.
In this installation, the unit is offset to keep the window visible and accessible, while the front-mounted fan remains oriented toward an open area.
Horizontal discharge: a real advantage when outdoor space is limited
The MIDEA EVOX G3 uses a large front-mounted fan with horizontal discharge. This architecture makes the unit relatively slim compared with some older cube-shaped central units.
Midea's documentation specifically highlights this horizontal discharge design, combined with a vertical heat exchanger intended to promote uniform heat exchange.
For a house like the one photographed in Saint-Chrysostome, this layout makes it possible to keep the unit relatively close to the building without having it extend excessively into the yard.
Front clearance nevertheless remains essential. A heat pump must not discharge its air directly against a fence, wall, or another obstacle located too close, as some of that air could return toward the heat exchanger and reduce performance.
A central heat pump designed to operate down to -30 °C
One of the main advantages of the MIDEA EVOX G3 Extreme Heat is obviously its ability to provide heating in cold weather.
According to Midea’s documentation, the platform can continue operating down to -30 °C. The manufacturer also indicates up to 100% heating capacity at -25 °C, with a COP of up to 1.9 under the reference conditions presented.
The page devoted to low-temperature operation also explains the compressor technology used to support performance when the mercury drops. Midea states that under extreme conditions, the system uses intermediate-temperature vapor injection to increase the amount of compressed refrigerant and thus maintain more heating capacity.
For our installations in Quebec, these performance figures are much more significant than a simple nominal BTU rating.
A central heat pump in Saint-Chrysostome should be selected based on what it can deliver in January, not solely on what it produces when outdoor temperatures are mild.
EVOX G3: multiple capacities, not a single tonnage
It is important not to present “EVOX G3” as though it were a single machine with one specific capacity.
The Midea family documented here includes several combinations of indoor and outdoor units. The brochure’s range extends from 18,000 to 54,000 BTU/h in cooling mode, with efficiency ratings that vary depending on the capacity and installed combination. Midea advertises performance for this entire family of up to 19 SEER2, 12.5 EER2, 10.8 HSPF2, and a COP of 2.14 at 5 °F, or approximately -15 °C.
The manufacturer’s technical table indicates, among other things:
- 18,000 BTU/h: up to 19 SEER2;
- 24,000 BTU/h: up to 18.6 SEER2;
- 30,000 BTU/h in cooling mode: 17.2 SEER2;
- 36,000 BTU/h: 17.7 SEER2;
- 48,000 BTU/h: 17.5 SEER2;
- 54,000 BTU/h: 17.5 SEER2.
The exterior photo of this installation does not allow us to read the unit’s full model number with certainty. We therefore do not arbitrarily assign it a specific tonnage. In a real installation, the exact capacity must always be confirmed using the indoor and outdoor model numbers, rather than estimated solely from the cabinet dimensions.
Why we avoid oversizing a central heat pump
In heating, “bigger” does not mean “better.”
A central heat pump must match the building's actual heating needs and the capabilities of the ductwork system.
In our analysis, we consider in particular:
- heated floor area;
- insulation level;
- window area;
- the building's orientation;
- air infiltration;
- ceiling height;
- the available airflow in the ductwork;
- the capacity of the auxiliary heating;
- the home's electrical capacity;
- heat losses when the outdoor temperature drops sharply.
An oversized system may operate in a less favorable range for much of the year. An undersized unit, on the other hand, may increase the use of auxiliary heating.
That is why replacing a central system should not be limited to matching the tonnage of the old unit.
The inverter changes how the system heats the home
The EVOX G3 is an inverter central heat pump.
Unlike a traditional compressor that essentially operates in on-off cycles, an inverter can adjust its speed according to the heating demand.
This modulation allows the system to adapt more precisely to temperature changes. A home almost never needs its maximum capacity throughout the entire season.
In the fall or spring, demand may be relatively low. During a January night, it increases significantly.
The ability to modulate capacity therefore contributes to more gradual operation, a more stable indoor temperature, and more efficient use of the available capacity.
The outdoor unit is only half of the system
The photo shows the most visible part of the project, but a central heat pump cannot be evaluated solely based on its outdoor compressor.
Inside is an air handler connected to the home's ductwork.
This component distributes heating and cooling throughout the various rooms.
Midea specifically developed the EVOX G3 to facilitate several central system replacement projects. The documentation indicates multivoltage compatibility at 115 V and 208/230 V for the indoor unit, as well as cabinet widths ranging from 14.5 to 21.5 inches depending on capacity, dimensions designed to fit several older furnaces.
During a renovation, this feature may limit certain modifications to the mechanical room and ductwork.
A modular indoor unit for difficult mechanical spaces
Not all existing homes have a large mechanical room with direct access.
Sometimes, the equipment has to pass through a narrow staircase. In other cases, ceiling height is limited, or the return air requires a particular orientation.
The EVOX G3 features a modular design allowing six installation configurations, including upflow, downflow, left- or right-horizontal discharge, as well as « low-boy » arrangements. The manufacturer also highlights a system of modules that can be separated to facilitate transport and reconfiguration.
For us, this flexibility is particularly interesting in replacement projects.
However, it does not change the fundamental rules: the equipment must remain accessible, the drainage must be properly installed, and the duct network must provide sufficient airflow.
What we check beyond the equipment when installing a MIDEA EVOX G3
An excellent compressor cannot correct improperly sized ducts
The distribution network is one of the most important components of a central system.
Midea equips the EVOX G3 with Computational Constant Airflow 2.0 technology. According to the brochure, the indoor unit can adjust its fan speed to the system conditions, with a stated capacity of up to 1.2 in. of water column static pressure and up to 60 airflow adjustment levels.
This technology is useful when a network has varying resistance.
But it does not mean that an undersized duct suddenly becomes acceptable.
During our central heat pump projects, we always verify that the return and supply systems are consistent with the desired airflow.
Excessively high static pressure remains a signal to take seriously
An ECM motor can increase its effort to maintain airflow. But the more the fan has to compensate for excessive restriction, the more important it is to identify the cause.
It can result from a filter that is too small, insufficient return air, an overly restrictive transition, or improperly sized ducts.
The right goal, then, is not simply to run the fan harder, but to create a balanced HVAC system.
MERV 13: better filtration, provided sufficient surface area is planned
Midea offers a filtration module compatible with 1-, 2-, or 4-inch MERV 13 filters. The manufacturer states that these filters can capture more dust, pollen, particles, and pet dander while helping keep the indoor coil cleaner.
For a home in Saint-Chrysostome, this may be beneficial for indoor air quality.
But a higher-performance filter must be properly sized.
A small, highly restrictive filter surface can increase static pressure and reduce airflow. In a central HVAC system, we therefore seek to balance filtration, available surface area, and airflow.
Auxiliary heat that supplements the heat pump during peak demand
Even a heat pump designed to operate at -30 °C can be accompanied by auxiliary heat.
The EVOX G3 offers multi-stage electric heater kits that can reach 25 kW depending on the configuration. Midea indicates that this backup heat can be controlled and adjusted according to temperature variations.
The heat pump's minimum operating temperature should not be confused with the temperature at which it necessarily covers 100% of the heat loss in every home.
A home with a high heating load may need backup heat during the coldest periods.
Our role is therefore to select and adjust this backup heat coherently, rather than letting it take over too quickly and unnecessarily increase electricity consumption.
A platform compatible with different types of controls
Midea has also provided several control options for this EVOX generation.
The documentation indicates compatibility with 485 communication, certain 24 V thermostats and, depending on the configuration, wireless communication between EVOX components.
With the Midea communicating thermostat and the SmartHome app, the manufacturer also presents features such as schedule programming, comfort monitoring, certain consumption information, and diagnostic functions.
During a renovation, this flexibility can be particularly useful if the existing wiring is difficult to replace.
R-454B: a new generation of refrigerant
The MIDEA EVOX G3 uses R-454B refrigerant.
According to Midea, the R-454B used in this range has a global warming potential, or GWP, of 466.
This refrigerant belongs to the A2L category and requires adapted work methods.
For our teams, this means that the refrigerant installation must be carried out using the appropriate practices and tools: connecting the lines, leak testing, evacuation, checking the charge, and commissioning.
The refrigerant change is therefore not merely a new entry on the nameplate. It is part of the technical evolution of today's HVAC systems.
The lines must remain protected and accessible
In the photo of the Saint-Chrysostome project, the connections leave the back and side of the unit toward the building.
When installing a central heat pump, we must avoid creating excessively tight bends in the refrigerant lines and preserve access to the service panels.
We are also thinking about future HVAC maintenance.
A technician must be able to return several years later to perform an electrical inspection, check the compressor's operation, clean the heat exchanger, or access the connections without having to dismantle components that could have been positioned elsewhere from the outset.
Three mistakes we want to avoid on an installation like the one in Saint-Chrysostome
Installing the outdoor unit flush with the ground
For a heat pump used all winter, this increases the risks associated with snow and defrosting. The wall brackets visible here provide much more appropriate clearance.
Neglecting the indoor air return
A high-performance outdoor unit cannot compensate for a duct system that is unable to move the required amount of air.
Confusing the range's maximum efficiency with the efficiency of the installed model
The 19 SEER2 or 10.8 HSPF2 values are range maximums, not values that automatically apply to all EVOX G3 units. Exact performance depends on the certified combination of the indoor and outdoor models.
LogisVert: the exact combination number is essential
For a Quebec installation, Hydro-Québec's LogisVert program can provide significant financial assistance.
Since November 26, 2025, installed heat pumps must be ENERGY STAR certified to be eligible. For a central heat pump, the complete system - outdoor unit and indoor unit - must meet the program requirements.
Hydro-Québec currently indicates assistance of $50 per 1,000 BTU/h of heating capacity at -8 °C for an eligible ENERGY STAR heat pump, or $120 per 1,000 BTU/h at -8 °C when it is certified ENERGY STAR – Cold Climate.
This is an important point: the amount is not calculated simply from the commercial designation "3 tons" or "36,000 BTU".
The value used is that of the eligible combination at -8 °C.
At AirGreen, we therefore verify the outdoor model, indoor model, and certified combination before announcing a subsidy amount. This prevents us from presenting the homeowner with an estimate based on a capacity that is not recognized by Hydro-Québec.
A simple outdoor installation, but one that is technically well thought out
The success of this MIDEA EVOX G3 installation in Saint-Chrysostome lies precisely in choices that may appear simple in the photo.
The unit is elevated enough to account for winter conditions. The front fan remains completely unobstructed. The heat pump does not rest on the ground. It does not block the nearby basement window. The brackets hold it directly against the structural part of the foundation while allowing access beneath the unit.
These are visible details, but they reflect a broader logic.
A central heat pump is a system in which the outdoor unit, indoor unit, ductwork, thermostat, filtration, auxiliary heating, and electrical supply must work together.
The EVOX G3 offers a technically interesting platform for Quebec's climate: operation rated down to -30 °C, inverter technology, several capacities, R-454B refrigerant, a modular indoor unit, and advanced airflow management.
Our work at AirGreen consists of turning these catalog specifications into an installation that is truly suited to the residence.
It is this same approach that we apply to our MIDEA central heat pump projects in Saint-Chrysostome, Montreal, Laval, Longueuil, on the South Shore and on the North Shore: size the system correctly, install it properly, and think from the outset about the performance the homeowner will expect when summer temperatures are very high or outdoor temperatures drop well below freezing.
How it goes, from the first call to the end
The main steps of this kind of job at AirGreen. Every house has its quirks: the estimate brings them out.
We look at the ducts, the current indoor module, the electrical panel and the planned spot for the outdoor unit.
The equipment combination, capacity and price, in writing. We check whether the combination qualifies for assistance programs.
Access protected, old unit disconnected and removed when it is being replaced.
Electric furnace or air handler, with its coil, connected to the supply and return ducts.
On a level base, raised above the snow, with free space all around.
Insulated, they enter through a sealed opening and run to the indoor coil.
Dedicated circuits, accessible disconnect, a thermostat that works with the heat pump and the backup heat.
Leak test, vacuum, start-up, airflow check and a test of both modes.
Filter, thermostat, backup heat in extreme cold: what to know before winter.
- The on-site estimateWe look at the ducts, the current indoor module, the electrical panel and the planned spot for the outdoor unit.
- The quoteThe equipment combination, capacity and price, in writing. We check whether the combination qualifies for assistance programs.
- Getting readyAccess protected, old unit disconnected and removed when it is being replaced.
- The indoor moduleElectric furnace or air handler, with its coil, connected to the supply and return ducts.
- The outdoor unitOn a level base, raised above the snow, with free space all around.
- The refrigerant linesInsulated, they enter through a sealed opening and run to the indoor coil.
- Electrical and thermostatDedicated circuits, accessible disconnect, a thermostat that works with the heat pump and the backup heat.
- Tests and start-upLeak test, vacuum, start-up, airflow check and a test of both modes.
- The walkthroughFilter, thermostat, backup heat in extreme cold: what to know before winter.
What the unit delivers when it is cold
The range as published on airgreen.ca: pick a size to see its capacity in deep cold.
| Size | Heating at −8 °C | Heating at −15 °C | Coldest certified point | COP at −15 °C | SEER | HSPF | Indicative LogisVert aid |
|---|---|---|---|---|---|---|---|
| Midea EVOX G3 · 1.5 tons | 14,700 | 18,600 | −30 °C: 11,800 | 2.12 | 19.0 | 10.1 | $1,764 |
| Midea EVOX G3 · 2 tons | 20,800 | 20,600 | −30 °C: 12,100 | 2.14 | 18.6 | 10.0 | $2,496 |
| Midea EVOX G3 · 2.5 tons | 24,000 | 33,200 | −30 °C: 17,900 | 1.97 | 17.2 | 10.8 | $2,880 |
| Midea EVOX G3 · 3 tons | 33,000 | 37,400 | −30 °C: 27,600 | 1.9 | 18.0 | 10.0 | $3,960 |
| Midea EVOX G3 · 4 tons | 39,500 | 48,000 | −30 °C: 27,200 | 2.0 | 17.5 | 9.5 | $4,740 |
| Midea EVOX G3 · 5 tons | 45,000 | 54,000 | −30 °C: 37,300 | 1.9 | 17.5 | 9.5 | $5,400 |
Data read live from the airgreen.ca page of each size (NEEP / AHRI certified performance). When the title names the installed size, it is highlighted; otherwise the whole range is shown. The aid shown is today’s, using Hydro-Québec’s rule ($120 per 1,000 BTU/h at −8 °C); amounts quoted in the article date from its publication. Only Hydro-Québec confirms the assistance granted.
And at your place?
Two quick checks with real numbers: what heat costs, and what your current heaters add up to in BTU/h.
Baseboards and electric furnaces turn 1 kWh of electricity into 1 kWh of heat. A heat pump delivers more: that is its COP. At Hydro-Québec’s rate D (11.142¢/kWh above 40 kWh a day, since 1 April 2026):
Hydro-Québec: a heat pump can be up to three times more efficient than baseboards for heating in the colder months.
Estimate per kWh of heat, at the chosen temperature, using the certified COP from the product page. Taxes, access charge and backup heat not included.
Conversion: 1 W = 3.412 BTU/h. An indication, not a load calculation: baseboards and furnaces are often stronger than the real need, and they can stay as backup. AirGreen confirms the capacity on site.
What to do, season by season
Three habits per season for this unit. They take a few minutes and prevent many calls.
- Check the indoor module's filter.
- Clear winter debris from the outdoor unit.
- Test cooling before the heat arrives.
- Check the filter more often in peak season.
- Keep registers and returns clear.
- Watch condensate drainage near the coil.
- Change or clean the filter.
- Test heating and backup heat before the cold.
- Book periodic maintenance.
- Clear snow around the outdoor unit.
- Store nothing in front of the indoor module.
- Note any unusual noise or smell and call us.
Which type of equipment for your project?
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Four mistakes we do not make
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What people ask us about this kind of work
Can I keep my current ducts?
What happens in extreme cold?
Furnace, air handler, ducted: what is the difference?
Are there grants?
Do I need a permit?
How much can I save?
How is the LogisVert assistance calculated?
Will my current thermostat work?
Central or wall units: which one?
Does AirGreen hold the required licences?
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Text and photo: a real AirGreen Climatisation & Chauffage job. The diagrams are generic illustrations of the type of installation, not a survey of this job site. Sources of the added figures: airgreen.ca product pages (NEEP / AHRI performance), Hydro-Québec (Heat pumps page, LogisVert, read on 13 October 2026), Régie de l’énergie (rate D as of 1 April 2026).