Installation of a MIDEA EVOX G3 central heat pump in Contrecœur, Montérégie
In Contrecœur, AirGreen installs a MIDEA EVOX G3 central heat pump on a rooftop: an R-454B inverter system, heating down to -30 °C, adaptive airflow, and installation designed for Quebec’s climate.
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 MIDEA EVOX G3 installation on a roof where the positioning of the outdoor unit becomes an essential part of the project
This MIDEA EVOX G3 central heat pump installation in Contrecœur clearly shows why replacing or modernizing an HVAC system is never simply a matter of choosing a unit from a catalog. On this project, the outdoor unit had to be integrated into a specific architectural configuration: flat roof, masonry wall, substantial roof overhang, and a technical area that had to remain accessible.
The photo taken during the work is particularly revealing. The Midea outdoor unit is already in place on a raised structure, while our connection and commissioning equipment is still in front of the unit. We can see the insulated refrigerant lines leading to the building, the nearby electrical connection, and, above all, the condenser fan oriented toward the large open area rather than the façade.
This detail is directly consistent with the design of the EVOX G3. For this generation, Midea uses an outdoor unit with horizontal discharge paired with a vertical heat exchanger, an architecture developed to maintain uniform and efficient heat exchange.
In an installation in Contrecœur, this design makes perfect sense: airflow, snow accumulation, defrost water drainage, service accessibility, and the building's constraints all need to be considered at the same time.
Why not simply place the outdoor unit directly on the roof?
The photo shows that we did not place the condenser directly on the roof membrane. The unit is installed on a raised metal frame, which is itself supported above the roof surface.
This additional height addresses several practical considerations.
In winter, a central heat pump operating in heating mode must be able to breathe even when it snows heavily. It also produces water during its defrost cycles. A unit installed almost level with the roof could be more exposed to snow, ice, or water accumulating around its base.
The elevation helps preserve:
- clearance beneath the unit;
- drainage of defrost water;
- access to the connections;
- the clearance around the fan and heat exchanger;
- a separation between the mechanical equipment and the roof surface.
On this job, the chosen position also keeps the discharge side completely unobstructed. The large fan visible in the photo expels air outside the technical area rather than directly toward the stone wall.
This is something we systematically analyze during a central heat pump installation in Montreal, Laval, Longueuil, on the North Shore, or the South Shore: a high-performance condenser cannot deliver the expected efficiency if its discharged air is continuously recirculated toward its own heat exchanger.
The photo was taken during commissioning, and that tells another part of the story
The work is still underway in the image. In front of the Midea unit, we can see the hoses, refrigeration tools, and equipment required for the connection and commissioning operations.
This is a less photogenic part than a completed system, but technically much more important.
An Inverter central heat pump depends on a properly prepared refrigeration circuit. After the mechanical installation come the connections, leak checks, circuit preparation, evacuation, and operational checks, among other steps.
We also monitor the path of the copper lines. Here, the lines exit the outdoor unit, form a controlled curve, and then enter the building. We seek to avoid sharp angles, unnecessary strain on the connections, and unprotected lines.
On a roof, this attention is even more important because the installation will be exposed year-round to temperature fluctuations, sunlight, freezing conditions, rain, and snow.
EVOX G3: a central heat pump specifically suited to extreme cold
The feature that immediately catches our attention with the MIDEA EVOX G3 is its performance in low temperatures.
According to Midea’s technical documentation, the Extreme Heat range can continue operating down to -30 °C. The manufacturer also indicates up to 100% heating capacity at -25 °C, with a COP of approximately 1.9 under the test conditions presented for its 3-ton system.
The compressor technology presented by Midea uses intermediate vapor injection when conditions become very cold to increase the amount of compressed refrigerant and support heating capacity.
For a Quebec residence, this is not a secondary feature.
A central heat pump is often purchased primarily to reduce the use of auxiliary electric heating elements or an older heating system. Its performance when the outdoor temperature is +5 °C is therefore noteworthy, but its capacity when the mercury drops to -15, -20, or -25 °C is even more important.
This is especially true in areas such as Contrecoeur and the Montérégie, where the equipment must transition, during the same season, from relatively mild days to much more demanding cold spells.
Efficiencies that vary according to the selected capacity
The EVOX G3 is not a single appliance with a single capacity. It is a range of central systems.
The Midea brochure presents configurations ranging from approximately 18,000 to 54,000 BTU/h of cooling capacity, depending on the selected indoor–outdoor unit pairing. The best advertised efficiencies in this range reach 19 SEER2, 12.5 EER2, and 10.8 HSPF2, with a COP at 5 °F of up to 2.14 depending on the configuration.
The manufacturer’s technical table clearly shows why we insist on the complete model number when preparing a quote.
For example, according to the configurations presented by Midea:
- an 18,000 BTU version reaches up to 19 SEER2;
- a 24,000 BTU configuration is listed at 18.6 SEER2;
- the configuration around 30,000 BTU reaches 17.2 SEER2 and 10.8 HSPF2;
- the 36,000 BTU version is listed at 17.7 SEER2;
- the largest 48,000 and 54,000 BTU configurations are listed at 17.5 SEER2 in the supplied table.
The exact capacity installed at a property must therefore always be confirmed using the indoor and outdoor models, rather than simply the EVOX G3 name.
Airflow is just as important as BTUs
A common mistake when replacing a central system is to focus the entire analysis on the heat pump’s capacity.
However, a central heat pump works with the building’s ductwork. If this network creates significant resistance or if airflow is inadequate, even an excellent compressor cannot correct every problem.
Midea equips the EVOX G3 with its Computational Constant Airflow 2.0 technology, designed to adapt fan operation to system conditions.
The documentation indicates operation up to 1.2 in. of external static pressure and up to 60 air volume adjustment levels. The system adjusts the power and fan speed to compensate for varying duct, filtration, or fouling conditions.
For us, this technology does not mean that duct sizing becomes unnecessary. A poorly designed ventilation network must still be evaluated. However, it provides very useful flexibility when replacing an old system in a home where the entire duct network will not be rebuilt.
An indoor air handler designed to facilitate replacements
One of the most interesting aspects of the EVOX G3 is precisely its focus on replacing an existing furnace or central system.
Midea announces cabinets with dimensions comparable to those of many gas furnaces of the same capacity, with widths ranging approximately from 14.5 to 21.5 inches. The manufacturer also presents an adaptive power supply that, depending on the configuration, can operate at 115 V or 208/230 V without manually modifying the equipment.
This can make a considerable difference in an already finished basement.
We regularly encounter homes where:
- the mechanical room is narrow;
- the water heater is immediately next to the unit;
- the return air leaves very little room to maneuver;
- the ceiling height limits the choice of air handler;
- the existing ducts cannot be easily moved.
Under these conditions, a few inches of difference can turn a relatively simple installation into a project requiring significant sheet metal modifications.
Six possible configurations for the indoor air handler
Midea has also developed the EVOX G3 indoor unit for multiple orientations.
The documentation presents six installation configurations, including upflow, downflow, right- or left-horizontal installations, as well as “low-boy” configurations suited to height restrictions.
The Block N Lock modular design allows the unit's sections to be separated and reconfigured. Midea particularly highlights the value of this system in basements, attics, and spaces where moving a single-piece air handler would be difficult.
On our AirGreen projects, this versatility interests us because it increases the chances of keeping a clean installation without sacrificing access to the filter, coil, or electrical components.
From R-454B to LogisVert: what a homeowner should really check before choosing their EVOX G3
The EVOX G3 generation stands out not only for its compressor and indoor unit. It also marks Midea's transition to R-454B refrigerant for this product line.
R-454B is now part of the system design
Midea states that it selected R-454B for this entire product range and assigns it a global warming potential, or GWP, of 466.
R-454B belongs to the A2L category of mildly flammable refrigerants. For the owner, this does not change how they adjust the thermostat day to day. For the HVAC company, it means that methods, equipment, and procedures must be adapted to the requirements of this new generation of refrigerants.
The Contrecoeur photo shows an installation still at the technical stage: before handing a system back to the owner, we want to have completed and checked the entire circuit, not simply confirmed that the outdoor fan is running.
Auxiliary heating: up to 25 kW depending on the configuration
Even a heat pump capable of operating down to -30 °C is normally integrated into a complete heating strategy.
For the EVOX G3, Midea provides optional three-stage auxiliary electric heating elements, with capacities of up to 25 kW, depending on the configuration. The control can activate and adjust these stages based on temperature changes.
The difference between "minimum operating temperature" and "sizing to heat the entire home without auxiliary heat" is fundamental.
A unit capable of continuing to operate at -30 °C is not automatically sized to cover 100% of any home's heat loss at that temperature.
We therefore assess the home's heating load, the heat pump's actual low-temperature capacity, and the electric auxiliary heat output before determining the best configuration.
MERV 13 filtration that can be integrated without improvising the return air
Filtration quality is also better integrated into this generation.
Midea offers a module compatible with 1-, 2-, or 4-inch MERV 13 filters. The manufacturer explains that this filtration is intended in particular to capture dust, pollen, particles, and pet hair or dander, while also helping keep the evaporator coil cleaner.
However, one essential rule must be kept in mind: more filtration also means potentially greater resistance to airflow.
We therefore do not arbitrarily replace a thin filter with a highly restrictive filter without considering the return air, filter surface area, and available static pressure.
That is precisely where the EVOX G3's flow control and proper system design must work together.
Midea thermostat, 24 V, and modernization options
For a renovation, control compatibility can prevent a great deal of work.
The EVOX G3 documentation indicates compatibility with 485 or a 24 V control, as well as automatic identification of the control mode. It provides for combinations with EVOX components, a Midea thermostat, or certain third-party 24 V thermostats.
Midea also describes Sub-1 GHz wireless communication between certain components, which can reduce the need to run a new communication cable between multiple sections of the system.
In a finished home, with closed ceilings and renovated walls, this type of flexibility can be much more valuable than it may appear in a brochure.
SmartHome app and diagnostics
With the Midea communicating thermostat, the system can also integrate various smart functions: scheduling, comfort control, consumption monitoring, and diagnostic or remote update features described by the manufacturer.
The benefit is not limited to being able to change a temperature from a phone.
For a modern Inverter central system, the ability to view more operating data can make it easier to analyze situations where the owner notices a change in behavior or when we need to diagnose a problem.
LogisVert: never calculate the incentive solely from the name “EVOX G3”
In Quebec, the Hydro-Québec LogisVert program is obviously one of the factors to check when choosing a central heat pump.
In September 2026, Hydro-Québec states that a heat pump installed since November 26, 2025 must be ENERGY STAR certified to be eligible. For an ENERGY STAR Cold Climate heat pump, the residential incentive is $120 per 1,000 BTU/h of heating capacity at -8 °C, when all program conditions are met.
The amount is therefore not calculated simply based on the nominal capacity indicated in the model name.
Hydro-Québec uses the exact certified combination, and its tool allows searches by ENERGY STAR number or AHRI number, among other options. In case of a discrepancy, Hydro-Québec specifies that its official list of eligible heat pumps takes precedence.
For a MIDEA EVOX G3, we therefore recommend checking before promising an amount:
- the exact model of the outdoor unit;
- the exact model of the indoor air handler;
- the AHRI or ENERGY STAR number associated with this combination;
- the certified heating capacity at -8 °C;
- the actual installation date;
- the presence of the combination on the applicable LogisVert list.
It is much more precise than announcing a rebate simply because the unit is described as a « -30 °C » heat pump.
What the Contrecœur photo teaches us about a good central installation
This installation is interesting because it allows us to observe the work before all the tools have been put away.
We see a MIDEA EVOX G3 central heat pump installed on an existing roof, raised and positioned to preserve substantial clearance in front of the fan. The refrigerant lines follow a relatively short route to the building. The electrical supply is accessible. The unit remains reachable for future service.
These choices seem simple once the work is complete. Yet they are made before the final connection.
A poor position by just a few dozen centimetres could complicate the routing of the lines, place the fan too close to the wall, make the service panel difficult to access, or create a problem area for snow.
Our job is therefore to consider the HVAC installation as a whole, rather than as two units connected by copper lines.
An EVOX G3 must be adapted to the building, not the other way around
This is probably the most useful point for a homeowner currently comparing several quotes for central heat pumps in Contrecœur, Montreal, Laval, Longueuil, on the North Shore or the South Shore.
The technical specifications are important. SEER2 is important. HSPF2, low-temperature capacity, and the rebate are important.
But first and foremost, concrete questions must be answered properly:
What capacity actually matches the home's heat loss? Can the ductwork provide the required airflow? Where will the outdoor unit be installed? How will defrost water be drained? Can the electrical panel support the unit and its auxiliary heating? Will the filter be accessible? What exact combination is eligible for LogisVert?
We build a project based on these answers.
In Contrecœur, this MIDEA EVOX G3 installation illustrates this approach perfectly: a unit designed for cold climates, but installed according to the home's physical characteristics. This is also the method we apply at AirGreen for our central heat pump installations in Greater Montreal, in Laval, Longueuil, Montreal, on the North Shore and on the South Shore.
The goal is not simply for the system to start up when the work is finished. We want it to be able to heat, cool, defrost, circulate air, be serviced, and operate with the home's ventilation system for many seasons.
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?
Pick what looks like your need.
Four mistakes we do not make
Flip each card to see what we do instead.
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?
Is the estimate free?
No question matches. Write to us: we answer.
Useful pages for what comes next
More jobs to see, near you
By town, by equipment or by region: browse more than 4,700 published projects.
Each dot: a town where AirGreen has published projects. The glowing dot: this job.
Tell us about your house. We come and see it for free.
The on-site estimate is free and the quote follows within 24 hours.
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).