Installation of a MIDEA EVOX G3 central heat pump in Outremont, Montreal
In Outremont, AirGreen installs a MIDEA EVOX G3 central heat pump on an elevated metal stand in a narrow passageway. Heating down to -30 °C, R-454B, ductwork, connections, and HVAC expertise explained in detail.
Take a tour of the installation
Each number is a point we check on site. Switch between summer and winter to watch air and heat move.
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 in a narrow side passage, with a raised support, service access, and carefully planned connections
In Outremont, we completed this MIDEA EVOX G3 central heat pump installation in a setting very different from a large open lot. The photo taken during the work shows an outdoor unit installed in a relatively narrow side passage, along a masonry wall, with several existing constraints: stone cladding, an existing electrical disconnect, pavers on the ground, nearby outdoor equipment, and limited circulation space.
Rather than simply looking for the shortest route for the refrigerant lines, we had to consider the installation as a whole: unit height, airflow in front of the fan, access to the service valves, support stability, connections to the building, and available space for future HVAC maintenance.
The photograph also shows the project during installation. The tools are still on the ground, the refrigerant copper lines have not yet been fully integrated into their final finish, and the heat pump's service connections are visible. This is precisely the stage that makes it possible to understand what a central installation really involves: well before the unit starts up, the entire system must be prepared mechanically, electrically, and for refrigerant circulation.
A raised ground support rather than a unit placed directly on the pavers
One of the immediately visible features in Outremont is the independent metal structure used beneath the outdoor unit.
Here, the MIDEA EVOX G3 rests neither directly on the pavers nor on a small slab placed a few centimeters above the ground. We used a raised-leg support that significantly elevates the heat pump.
For a central heat pump intended to operate during the winter, this height serves several purposes.
In heating mode, the outdoor coil naturally accumulates frost when certain temperature and humidity conditions occur. The unit must then run defrost cycles. The water released during this process must be able to drain from underneath the unit.
An installation that is too low can lead to:
- progressive ice buildup;
- obstruction underneath the unit after several snowfalls;
- difficult access for inspections;
- increased contact with leaves, soil, or debris;
- much more restrictive service work.
On this Outremont installation, the height of the structure creates significant open space beneath the chassis.
A freestanding support particularly well suited to this configuration
The photo also shows that the support is installed directly on the paved surface, with several feet and support plates.
This choice supports the unit without necessarily transferring the entire load and vibrations directly to the masonry wall.
In a narrow side passage, this type of support can also facilitate precise positioning of the unit. We can adjust its location to preserve the clearances, refrigeration connections, and circulation around the system.
The support must, of course, be stable. An inverter heat pump contains a compressor and a large fan that generate normal movement during operation. The mechanical quality of the base therefore plays a role in the overall stability of the installation.
An installation where access to the refrigeration valves had to remain unobstructed
On the right side of the unit, the refrigeration connections, service valves, and copper piping are clearly visible.
When a heat pump is placed in a confined space, it would be easy to push the unit too close to the wall or another obstacle to gain a few inches.
We avoid this approach.
Refrigeration components must remain accessible for:
- pressurization during leak-tightness testing;
- vacuum evacuation;
- checks during commissioning;
- future diagnostics;
- any necessary repairs;
- the measurements taken during HVAC maintenance.
The Outremont photo is particularly interesting for this reason: it directly shows the part of the installation that often disappears from view once the lines are completed and protected.
The copper must not be forced to fit into a confined space
The lines visible in the photo are still being installed.
Refrigeration-grade copper requires careful handling. We want to maintain suitable bends and avoid creating unnecessary strain on the connections.
A line that is bent too sharply can be damaged or restricted.
In a project like this, where the heat pump is installed parallel to the wall and the available passage is relatively limited, we must therefore plan the routing before finalizing the connections.
A MIDEA EVOX G3 designed for low-temperature heating
The MIDEA EVOX G3 Extreme Heat was designed for heating applications in cold climates.
Midea's documentation indicates continuous operation down to -30 °C. The manufacturer also presents up to 100% heating capacity at -25 °C, with a COP of up to 1.9 under the indicated reference conditions.
These characteristics are particularly relevant in an installation in Montreal.
When a homeowner invests in a central heat pump, the real question is not only whether it cools well in July. We also want to know whether it can continue providing heat when the outdoor temperature drops sharply.
Midea's documentation also describes compressor technology using intermediate-temperature vapor injection in cold conditions to increase the amount of compressed refrigerant and support heating performance.
Up to -30 °C does not mean that all auxiliary heating should automatically be eliminated
One point needs to be clarified.
The minimum operating temperature advertised for a heat pump is not the same thing as the capacity needed to cover each home's heat losses.
One residence may require 25,000 BTU/h under certain conditions, while another property of comparable size may need much more because of its insulation, windows, or air infiltration.
We therefore size the system based on the property's needs, not solely on the minimum temperature indicated in the brochure.
EVOX G3: a family of systems, not a single capacity
The name MIDEA EVOX G3 encompasses several configurations.
The technical documentation covers systems ranging from 18,000 to 54,000 BTU/h in cooling, with different characteristics depending on the associated air handler and outdoor unit.
For the entire family, Midea indicates performance of up to:
- 19 SEER2;
- 12.5 EER2;
- 10.8 HSPF2;
- a COP of up to 2.14 at 5 °F, or approximately -15 °C.
The range's technical table includes configurations of 18,000, 24,000, 30,000, 36,000, 48,000, and 54,000 BTU/h in cooling, among others.
The plate visible in the photograph from Outremont is too small to confirm with certainty the exact combination installed. We therefore do not artificially assign it a precise tonnage.
To establish the exact performance of an installation, we always use the outdoor model number and the indoor model number.
Why this distinction matters for SEER2 and HSPF2 efficiency ratings
A common mistake is to read "up to 19 SEER2" for a series and then present all capacities as 19 SEER2 systems.
That is not the case.
In Midea's table, the 18,000 BTU/h configuration is listed at 19 SEER2, while the other capacities have their own ratings. For example, the configurations shown at 30,000 and 36,000 BTU/h have different SEER2 and HSPF2 ratings, respectively.
For a homeowner comparing two quotes, this nuance is important.
You need to compare the actual combination, not just the series name.
Behind the outdoor unit: what really determines the comfort of a central heat pump in Outremont
The indoor unit is designed to simplify replacements
A significant part of the EVOX G3's value is found inside the home.
Midea designed its air handler with a renovation-friendly approach. The documentation indicates 115 V and 208/230 V compatibility depending on the configuration, with adaptation to the required voltage.
The indoor cabinets are also available in widths of approximately 14.5 to 21.5 inches, to better match several common dimensions of older furnaces.
In Outremont, where we frequently work in existing properties rather than entirely open new construction, this flexibility can be very useful.
A mechanical room may contain:
- an old furnace;
- a water heater;
- plumbing lines;
- an existing chimney;
- ductwork built around a precisely sized unit;
- a relatively low ceiling.
A smart replacement seeks to work with this reality rather than unnecessarily requiring a complete reconstruction of the mechanical room.
Six configurations to adapt the air handler
Midea's documentation shows a modular design allowing six installation orientations, including upflow, downflow, right horizontal, left horizontal, and certain "low-boy" configurations.
This design can simplify installation in a basement where the existing ducts require a specific orientation.
It also makes it easier to transport the unit when access to the mechanical room is limited.
The ductwork is just as important as the heat pump itself
A central heat pump operates with the building's ductwork.
An excellent compressor cannot deliver its full potential if the airflow is inadequate.
Midea equips the EVOX G3 with Computational Constant Airflow 2.0 technology.
According to the documentation, the system can adjust the fan power based on network conditions and maintain airflow in situations involving up to 1.2 in. of static pressure in the examples provided. The manufacturer also indicates up to 60 airflow adjustment levels.
This technology is interesting, particularly during a renovation.
But it does not mean that the ducts can be neglected.
An advanced ECM motor does not automatically turn a poor duct system into a good one
If an air return is too small, the motor will have to work harder.
If a filter creates too much resistance, static pressure increases.
If a transition is extremely restrictive, the distribution system can become noisy.
We therefore check the entire system before and during commissioning.
MERV 13: good filtration also requires sufficient surface area
Midea offers a filtration module compatible with 1-, 2-, or 4-inch MERV 13 filters. The manufacturer indicates that this filtration can capture more dust, pollen, particles, and pet dander while helping keep the evaporator cleaner.
However, we always look at the filter size.
An MERV 13 filter that is too small for the required airflow can create excessive pressure loss.
For a central HVAC installation, the right balance is therefore:
filtration quality + sufficient filter surface area + appropriate airflow.
An auxiliary heater configurable up to 25 kW
The EVOX G3 platform can also accommodate a three-stage electric auxiliary heater capable of up to 25 kW depending on the configuration.
This supplemental heat remains relevant even with a heat pump capable of operating at very low temperatures.
It can engage when the home's heating needs temporarily exceed the heat pump's capacity.
However, the auxiliary heat setting is essential.
Improper programming can engage the electric resistance too early, reducing the heat pump's economic advantage.
Rather, we aim to allow the inverter compressor to cover as much of the demand as reasonably possible.
Inverter technology better suited to variable loads
A home's heating load never remains the same throughout the day.
In the fall, a home may require very little heating during the afternoon and much more during the night. In January, the load can increase considerably.
Inverter technology allows the compressor to adjust its operation rather than running only at full capacity and then stopping.
This modulation helps create more gradual heating and more stable comfort.
Several control options for renovations
Midea states that the EVOX G3 can operate with several types of control, including:
- communication 485;
- 24 V thermostats in certain configurations;
- wireless communication between certain components of the EVOX ecosystem.
In an existing property in Outremont, this flexibility can be very useful.
Replacing a thermostat wire in a finished home can sometimes require opening walls or ceilings. The various control options make it possible to choose a strategy suited to the existing installation.
The documentation also presents a Midea communicating thermostat and the SmartHome app, with features for scheduling, monitoring comfort, viewing certain consumption data, and diagnostics.
R-454B: the refrigerant in this new-generation EVOX
The MIDEA EVOX G3 uses R-454B refrigerant.
Midea indicates a global warming potential, or GWP, of for this A2L refrigerant 466.
For our technicians, the refrigerant used directly affects the installation procedure.
We must use the appropriate equipment and methods during:
- refrigerant connections;
- leak testing;
- vacuum evacuation;
- commissioning;
- for future service calls.
The photo also shows why access around the machine must be maintained
The side passage of this Outremont property is not very wide.
You can see bins farther away, an outdoor tank, service equipment, and a paved area used to move around the building.
We therefore had to avoid positioning the heat pump in a way that would completely block the passage.
The relatively slim design of the horizontal-discharge unit helps in this type of situation.
But we must also plan for a technician to return one day with tools, gauges, or cleaning equipment.
The future service must be part of the location choice from the initial installation.
The electrical disconnect is placed directly nearby
On the wall to the right, you can also see the electrical disconnect box.
Its location near the unit makes it easier to disconnect power locally during maintenance.
Electrical accessibility is essential for working safely during a diagnosis or service call.
Three mistakes this Outremont project helps avoid
Place the heat pump directly on the paving
An installation this low would considerably reduce the space available beneath the unit for snow and defrost water.
Placing the technical side against the wall
This would make the refrigerant valves and connections almost impossible to reach.
Underestimating the width of the passageway
A poorly positioned unit could make circulation, building maintenance or heat pump servicing unnecessarily difficult.
What about financial assistance?
The Midea brochure presents the EVOX G3 range as a very high-efficiency family and indicates that it exceeds certain ENERGY STAR specifications in the context presented by the manufacturer.
However, the documentation provided alone is not sufficient to confirm this Outremont installation’s precise eligibility for a Quebec program or to calculate a financial assistance amount.
The exact combination of the indoor and outdoor units and the corresponding certification must be verified.
At AirGreen, we prefer to confirm this information using the system’s exact references rather than announcing a subsidy based solely on the EVOX G3 name.
What we take away from this MIDEA EVOX G3 installation in Outremont
This project clearly illustrates what distinguishes a central heat pump installation from simply delivering equipment.
In the photo, we see a MIDEA installed on a raised metal structure in a relatively narrow passageway. The refrigerant lines are being connected, our technicians’ tools are still visible and the service panel remains fully accessible.
But the most important part lies in coordinating all the details:
- outdoor unit location;
- winter clearance;
- access for maintenance;
- refrigerant line routing;
- electrical supply;
- exact combination capacity;
- air handler;
- static pressure;
- filtration;
- auxiliary heating;
- thermostat;
- commissioning.
The MIDEA EVOX G3 offers a particularly interesting central platform thanks to its advertised operation down to -30 °C, inverter technology, R-454B refrigerant, modular indoor unit and advanced airflow management.
Our role at AirGreen is to ensure that these technical features actually work in the home where the system is installed.
This is the approach we apply to our central heat pump projects in Outremont, Montreal, Laval, Longueuil, on the South Shore and on the North Shore: analyzing the building, choosing the right capacity, preparing the ductwork and carrying out an installation that will remain accessible and perform well long after we leave.
The unit on this job, in figures
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.
The big day, step by step
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 would it look like 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.
Four mistakes we do not make
Flip each card to see what we do instead.
Your own project, step by step
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.
Is your home ready?
Check what applies at your place. A "no" is not a refusal: it is what we sort out during the estimate.
Four statements: true or false?
It all comes down to details you have just seen.
1. A central heat pump uses the house's ducts.
It connects to the existing ducts to heat and cool everywhere.
2. In extreme cold, electric backup heat can take over.
The indoor module (furnace or air handler) works with the heat pump and takes over in extreme cold.
3. The filter only gets changed when the unit breaks down.
A dirty filter cuts airflow. It gets checked regularly.
4. You can reuse the old unit's size without checking.
The house may have changed: insulation, windows, added rooms. Capacity is confirmed on site.
0 / 4 right answers
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.
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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).