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MIDEA EVOX G3 and MIDEA ATOM X central systems, stepping down to −30 °C
Two 3-ton MIDEA central heat pumps on R‑454B, offered by AirGreen and certified ENERGY STAR cold climate. NEEP tests them at the same four temperatures. They are close at −15 °C; at −30 °C, the certified capacity gap reaches 11,600 BTU/h.
What the electricity costs, in dollars, winter and summer
AirGreen estimate for the same 36,000 BTU/h house in Montréal, at Hydro-Québec Rate D, taxes included. Both heat pumps are calculated exactly the same way, with the same method as on all our comparison pages; only their certified efficiencies change. Electric baseboards serve as the reference. The EVOX G3 is certified at 36,000 BTU/h in cooling and the ATOM X at 34,000: the calculation uses their common nominal size, 3 tons.
How this amount is calculated
- Heat needed over the winter. A house whose heat loss reaches 36,000 BTU/h ( kW) at −23.1 °C, Montréal’s design temperature: kW × 24 h × 4,167 degree-days ÷ (18 − (−23.1)) = kWh of heat for round-the-clock heating, all winter. Heating degree-days (base 18 °C) and design temperature: Natural Resources Canada, HOT2000 climate data, Montréal Intl station. With fewer hours a day (“Heating” slider), the heat is reduced in the same proportion, for the heat pump and the baseboards alike: a simplification that ignores the recovery after a setback.
- Electricity for heating. Heat pump: heat × 3.412 ÷ HSPF2 Region V, the AHRI certificate value published by NEEP. Region V is the coldest in the standard, and its calculation includes the electric backup planned for when the heat pump is no longer enough. Electric baseboards: 1 kWh of electricity for 1 kWh of heat.
- Electricity for cooling. 36,000 BTU/h ÷ SEER2 × hours per day × 60 days ÷ 1,000: the method of Hydro-Québec’s air-conditioning calculator, with the SEER2 seasonal efficiency from the AHRI certificate. The number of hours is a scenario, adjustable above from 1 to 24 h. At 24 h, the calculation assumes rated capacity all day: that is a maximum, since a variable-speed unit slows down once the room is at the right temperature.
- Price. Hydro-Québec Rate D in effect April 1, 2026: 7.065¢ per kWh up to 40 kWh a day, 11.142¢ beyond; the average price, 9.104¢, is the one Hydro-Québec’s calculators use. GST and QST included. The network access fee, the same with or without a heat pump, is not counted.
AirGreen method v1.1, November 9, 2026. An estimate is for comparing units under the same conditions. The actual bill depends on the house, insulation, settings and use; this amount is not a promise.
Four certified steps, a gap that opens on the last one
Each step is a NEEP test temperature, the same for both units. The height of each block is the certified maximum heating capacity. The steps are spaced like stairs, not to the scale of degrees.
Percentages calculated by AirGreen: certified maximum capacity at each temperature ÷ each unit’s certified rated capacity at 8.3 °C (37,000 and 36,000 BTU/h). Yellow line: 100%. On its certificate, the ATOM X gives more at −15 °C (36,000 BTU/h) than at −8.3 °C (34,100 BTU/h); the page shows the values as published.
A central system and a mini-VRF, compared in central configuration
The EVOX G3 is a central heat pump with its MIDEA indoor unit. The ATOM X outdoor unit is a mini-VRF platform: MIDEA connects it to one central indoor unit or to several VRF indoor units. This page compares the two certified central combinations.
MIDEA EVOX G3Central heat pump, one outdoor unit and one indoor unit
- Piping246 ft maximum, 98.4 ft height difference (installation manual)
- Heating range−30 to 24 °C (−22 to 75 °F)
- Cooling range−30 to 50 °C (−22 to 122 °F)
- Backup heatthree-stage electric kit, up to 25 kW (leaflet)
MIDEA ATOM XMini-VRF platform, compared here with its central indoor unit
- Piping296 ft for the longest line, 984 ft in total (brochure)
- Heating range−30 to 30 °C (−22 to 86 °F)
- Cooling range−15 to 52 °C (5 to 125 °F)
- VRF indoor unitsup to 5 for the 3-ton, from 50 to 130% connected capacity (brochure)
Diagrams, not to scale. Sources: MIDEA EVOX Extreme Heat installation manual (rev. 5, October 23, 2025), EVOX G3 2025 leaflet; MIDEA ATOM X brochure (Midea Building Technologies, 2025), outdoor unit table.
Below −15 °C: every published figure, at its exact temperature
NEEP certifies both units at −15 °C and at −30 °C, the same temperatures: those two rows compare directly. MIDEA publishes no capacity table between those two points for either combination; at the temperatures in between, the page gives the range between the two certified points.
What MIDEA writes for each system
EVOX G3 submittal sheet, leaflet and installation manual; ATOM X brochure. Each row repeats what the manufacturer writes.
EVOX G3: twin-cylinder rotary EKPQ420D1UMUA; “M-Powevi” vapour injection in extreme cold (leaflet).
ATOM X: inverter compressor, mini-VRF platform (brochure).
EVOX G3: heating stated down to −30 °C; adjustable defrost algorithm (installation manual).
ATOM X: heating range from −30 to 30 °C (brochure).
EVOX G3: “2.0” constant airflow; 5 speeds, 971 to 1,236 CFM; 0 to 1.0 in w.c.
ATOM X: MIH36VMN10 central indoor unit; MIDEA publishes its values in its VRF documents.
EVOX G3: 485 or 24 V mode; MIDEA communicating thermostat; SmartHome app.
ATOM X: individual or central control of the VRF indoor units (brochure).
EVOX G3: three-stage kit, up to 25 kW (leaflet).
ATOM X: depending on the indoor unit chosen from the MIDEA VRF line.
Both: R-454B; factory charge of 127 oz (EVOX G3) and 109.3 oz (ATOM X).
How loud each one is, per MIDEA
MIDEA publishes the outdoor unit sound of both systems, and the EVOX G3 indoor unit sound by speed. The documents do not state the measurement method: read the values separately.
How to read these numbers. dB(A) measures noise level as the ear perceives it: the lower the number, the quieter the unit. Each point is a value published by MIDEA.
Why this is not a ranking. Two different documents, with no measurement method stated. Different or unknown method: not comparable.
Indoor unit, in the basement or a closet
Published values
ATOM X: the MIDEA brochure does not give the sound level of the MIH36VMN10 central indoor unit.
Outdoor unit, outside
Published values
Measurements taken by MIDEA with an unstated method, in two different documents: read them separately, not as a ranking.
Outdoors, side by side, and the piping
Outdoor units, width to scale
Width to scale; the photos are taken in perspective. W × H × D dimensions per the EVOX G3 submittal sheet and the ATOM X brochure.
What connects
EVOX G3: 3/8 – 3/4 in line set, 25 ft precharged, then 0.7 oz of R-454B per foot, up to 246 ft. ATOM X: 3/8 – 5/8 in line set; the brochure gives 296 ft for the longest line and 984 ft for the whole network when several VRF indoor units are connected.
| Installation | EVOX G3 | ATOM X |
|---|---|---|
| Maximum piping length | 246 ftMIDEA installation manual, rev. 5, October 23, 2025. | 296 ftLongest line; 984 ft in total, per the brochure. |
| Precharged length | 25 ft0.7 oz per foot beyond, submittal sheet. | Not stated in the ATOM X brochure |
| Maximum height difference | 98.4 ft | Not stated in the ATOM X brochure |
| Liquid – gas line diameters | 3/8 – 3/4 in | 3/8 – 5/8 in |
| Outdoor unit W × H × D, weight | 38 9/16 × 38 3/8 × 16 3/8 in, 204 lb | 40 11/16 × 34 × 20 9/16 in, 207 lb |
| Factory refrigerant charge | 127 oz of R-454B | 109.3 oz of R-454B |
| Stated heating / cooling range | −30 to 24 °C / −30 to 50 °C | −30 to 30 °C / −15 to 52 °C |
Sources: MIDEA MAUSE-H36B-2A / MO1SE-H36B-2A submittal sheet and EVOX Extreme Heat installation manual; MIDEA ATOM X brochure, outdoor unit table (MDV-V36WMN10T). The ATOM X brochure does not give the precharge, height difference or electrical protection for the 3-ton unit; the written quote specifies them for each installation.
What people ask about these two MIDEA systems
Where do the two systems differ most?
At −30 °C. NEEP certifies 27,600 BTU/h maximum for the EVOX G3 and 16,000 BTU/h for the ATOM X, at the same temperature. At −15 °C, the gap is only 1,400 BTU/h (37,400 and 36,000).
What does this gap mean for a house?
Measured against each unit’s rated capacity at 8.3 °C, the EVOX G3 keeps 75% at −30 °C and the ATOM X 44%. The rest of the heat comes from the backup planned at installation; the home’s heat-loss study says how much is needed.
Is the winter cost very different?
The estimated cost uses Region V HSPF2, 8.2 and 7.7: the yearly gap shown above follows from that, under the same calculation conditions.
What is the ATOM X “mini-VRF”?
Per the MIDEA brochure, the 3-ton ATOM X outdoor unit can supply one central indoor unit or up to 5 VRF indoor units controlled separately or together. This page compares the certified central combination MIH36VMN10 / MDV-V36WMN10T.
Which one makes less noise?
MIDEA publishes 63 dB(A) for the EVOX G3 outdoor unit and 59 dB(A) in cooling, 61 dB(A) in heating for the ATOM X, in two different documents and with no method stated: these numbers cannot be used to rank the units.
Are they eligible for rebates?
Per NEEP, both combinations are ENERGY STAR and ENERGY STAR cold climate. Eligibility depends on the official list in force on the date of purchase; this page promises no amount.
All AHRI and NEEP values
| Certified value | EVOX G3 | ATOM X |
|---|---|---|
| Cooling | ||
| Rated capacity at 35 °C | 36,000 BTU/h | 34,000 BTU/h |
| SEER2 | 18.0 | 17.0 |
| EER2 | 12.0 | 11.7 |
| Heating, same conditions | ||
| HSPF2 Region IV | 10.0 | 9.4 |
| HSPF2 Region V | 8.2 | 7.7 |
| 8.3 °C: min. / rated / max.BTU/h | 11,400 / 37,000 / 47,000 | 14,000 / 36,000 / 39,500 |
| 8.3 °C: COP min. / rated / max. | 4.45 / 3.50 / 3.27 | 4.46 / 3.60 / 3.09 |
| −8.3 °C: min. / rated / max.BTU/h | 11,000 / 33,000 / 41,500 | 7,880 / 31,200 / 34,100 |
| −8.3 °C: COP min. / rated / max. | 2.58 / 2.50 / 2.21 | 2.65 / 2.30 / 2.14 |
| −15 °C: min. / rated / max.BTU/h | 8,900 / 37,400 / 37,400 | 6,500 / 36,000 / 36,000 |
| −15 °C: COP min. / rated / max. | 2.16 / 1.90 / 1.90 | 2.14 / 1.90 / 1.90 |
| Coldest point — same temperature for both | ||
| Test temperature | −30 °C (−22 °F) | −30 °C (−22 °F) |
| Min. / max. capacity | 4,700 / 27,600 BTU/h | 3,000 / 16,000 BTU/h |
| COP at maximum capacity | 1.56 | 1.43 |
| Listings and refrigerant | ||
| ENERGY STAR / cold climate (NEEP) | Yes / Yes | Yes / Yes |
| AHRI certificate · NEEP record | 215471343 · 387396 | 216441717 · 438139 |
| RefrigerantGWP per the IPCC (AR4); ASHRAE 34 class | R-454B · GWP 466 · A2L | R-454B · GWP 466 · A2L |
higher marks the higher value of the same measure, under the same conditions. It is not a recommendation. Capacities and COPs at each point are not highlighted; they are compared in “The descent” and “Extreme cold”.
Both are on the AirGreen website.
To choose for your home, talk it over with our team: bring the heated floor area, the condition of your ducts and your current heating.
Where every figure comes from
Data verified on November 9, 2026. Performance: AHRI certificates and the NEEP database. Dimensions, sound, piping and features: per the manufacturer. When a source contradicts the AHRI certificate, the certificate prevails.
Trademarks. MIDEA, EVOX and ATOM X are trademarks of their respective owners. Logos are used only to identify the products compared. AirGreen is a dealer for the brand; this page is not produced, sponsored or endorsed by the manufacturer.
Photos: AirGreen and manufacturer, for identification.
Does a figure look wrong to you? Write to us: every reported figure is checked again.