What is the SEER2 rating of the Midea MASAG18-21HS2GB?

The Midea MASAG18-21HS2GB is rated at up to 19.5 SEER2 and 11.0 EER2 for cooling and up to 8.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the Midea MASAG18-21HS2GB good for cold climates?

It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 18,000 BTU model.

How much does the Midea MASAG18-21HS2GB cost to run per year?

At its rated efficiency it costs about $436-$1,326 a year in electricity in large U.S. cities, depending on climate and local rates - for example $560 in Phoenix and $1,125 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the Midea MASAG18-21HS2GB the same as the C&H CH-NY18MIA-230VO?

Yes, as far as the certified ratings go. ENERGY STAR lists both model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.

Which indoor units work with the Midea MASAG18-21HS2GB?

ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated one uses MIDEA MASAG18-21HS2GA.

What refrigerant does the Midea MASAG18-21HS2GB use?

It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and R-32.

18,000 BTU mini-split heat pump · MAS-series

Midea MASAG18-21HS2GB

Below average cooling and heating efficiency for a 18,000 BTU mini-split heat pump, but not rated for cold climates.

Ranks #429 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $539 a year to run in a mixed climate like Atlanta.

SEER2: 19.5 Cooling efficiency over a season
Below average · beats 12%
HSPF2: 8.7 Heating efficiency over a season
Below average · beats 5%
EER2: 11.0 Cooling efficiency on a 95°F day
Below average · beats 9%
Heat at 5°F: 11,700 BTU/h62% of its 47°F output
Average · beats 61%

A good fit if…

You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

You often see nights below 0°F - it is not cold-climate certified.
Cooling cost matters most - its SEER2 is below average for mini-splits.
You mainly need heat - its HSPF2 is below average for mini-splits.
You want the newest refrigerant - it uses R-410A, which is being phased down.

Calculate my running cost

Details

Specifications18,000 BTU, R-410A

General
Brand	Midea
Also sold as	C&H, Cooper&Hunter
Outdoor unit model	MASAG18-21HS2GB
Series	MAS-series
Type	Mini-split heat pump
Nominal size	18,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-410A
Connected (smart) capable	No
On the market since	May 15, 2022
Last certified	June 13, 2026
Cooling
SEER2Seasonal efficiency, higher is better	19.5 (range 19.5)
EER2Efficiency at 95°F outdoors	11.0
Cooling capacity	18,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.7
Capacity at 47°F	18,800 BTU/h
Capacity at 17°F	11,400 BTU/h
Capacity at 5°F	11,700 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	2.06
ENERGY STAR cold climate	No

Heating output as it gets colder62% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with MASAG18-21HS2GA at the standard test temperatures, in BTU/h:

Certified matchups2 indoor units

The same outdoor unit scores differently with each indoor unit. Ask your installer for the AHRI reference number of the exact system you are quoted.

Indoor unit	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
MASAG18-21HS2GA MIDEA	19.5	11.0	8.7	11,700	209847241
MASAG18-21HS2GA MIDEA	19.5	11.0	8.7	11,700	211871343

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the Midea MASAG18-21HS2GB: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

C&H CH-NY18MIA-230VO

Yearly running cost in 10 large cities$436-$1,326

Phoenix, AZ$560/yr
Miami, FL$436/yr
Houston, TX$503/yr
Atlanta, GA$539/yr
Los Angeles, CA$531/yr
New York, NY$1,326/yr
Chicago, IL$1,083/yr
Denver, CO$907/yr
Seattle, WA$562/yr
Minneapolis, MN$1,125/yr

At each state's average electricity price and the city's typical heating and cooling hours.

Questions6

What is the SEER2 rating of the Midea MASAG18-21HS2GB?: The Midea MASAG18-21HS2GB is rated at up to 19.5 SEER2 and 11.0 EER2 for cooling and up to 8.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the Midea MASAG18-21HS2GB good for cold climates?: It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 18,000 BTU model.
How much does the Midea MASAG18-21HS2GB cost to run per year?: At its rated efficiency it costs about $436-$1,326 a year in electricity in large U.S. cities, depending on climate and local rates - for example $560 in Phoenix and $1,125 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the Midea MASAG18-21HS2GB the same as the C&H CH-NY18MIA-230VO?: Yes, as far as the certified ratings go. ENERGY STAR lists both model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
Which indoor units work with the Midea MASAG18-21HS2GB?: ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated one uses MIDEA MASAG18-21HS2GA.
What refrigerant does the Midea MASAG18-21HS2GB use?: It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and R-32.

Running cost and savings

Pre-filled with this model. Pick your city and what you heat with today; everything else is optional.

Heat pump $567/yrYou save $374/yrSee details ↓

1. Where you live

StateCityElectricity ¢ per kWh

Adjust heating and cooling hours

Filled in from your city's climate. Change them if you run the system much more or less than usual.

Cooling hours full-load hours per yearHeating hours full-load hours per year

2. The heat pump Midea MASAG18-21HS2GB

Find a model (fills in the ratings below)

SEER2 cooling efficiencyHSPF2 heating efficiencyCooling capacity BTU/hHeating capacity BTU/h

3. What it replaces

Current heatingFurnace efficiency (AFUE %)Gas price, $/thermCurrent coolingOld AC rating SEER2 (10 ≈ 15+ years old)

4. Price replace the example with your quote

Installed price, $Rebates and incentives, $ utility, state

Heat pump, per year: $567
Current system, per year: $941
You save per year: $374
Payback: 18.7 years
Net after 10 years: -$3,257

Cooling $325Heating $242Electricity used: 3,543 kWhSaved vs. a minimum-efficiency heat pump: $157

Estimates use the unit's rated SEER2 and HSPF2, full-load hours derived from NOAA 1991-2020 degree days, average residential electricity prices from the U.S. EIA (12 months to July 2026) and fuel prices from EIA (2025 for natural gas, week of 2026-10-05 for propane and heating oil). Very cold days that need backup heat are not modelled. Federal minimum for comparison: 14.3 SEER2 / 7.5 HSPF2.

Similar 18,000 BTU models

Goodman MSH183G20MCAA19.5 SEER2 · 8.7 HSPF2
Comfort-Aire A-VMH18SU-1B19.4 SEER2 · 10.0 HSPF2
Arcoaire DLCERBH18AAK19.5 SEER2 · 8.7 HSPF2
Mitsubishi Electric MXZ-2D20NLHZ · cold climate19.3 SEER2 · 10.0 HSPF2
Panasonic CU-E18RKUA19.5 SEER2 · 9.0 HSPF2
Mainline ML18HP230GEN-O · cold climate19.2 SEER2 · 9.6 HSPF2
MDV MOX330-18HFN1-MS0W19.5 SEER2 · 9.1 HSPF2
Mitsubishi Electric SUZ-KA18NAHZ · cold climate19.2 SEER2 · 9.5 HSPF2

See all 465 18,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 13, 2026. How we use the data.