What is the SEER2 rating of the ROVSUN TMSC-18HA2/I2XI20B-O?

The ROVSUN TMSC-18HA2/I2XI20B-O is rated at up to 20.5 SEER2 and 11.0 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the ROVSUN TMSC-18HA2/I2XI20B-O good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,200 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.

How much does the ROVSUN TMSC-18HA2/I2XI20B-O cost to run per year?

At its rated efficiency it costs about $371-$1,269 a year in electricity in large U.S. cities, depending on climate and local rates - for example $496 in Phoenix and $1,090 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Which indoor units work with the ROVSUN TMSC-18HA2/I2XI20B-O?

ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use Rovsun RVC-12/I-D, Rovsun RVC-O9/I-D.

15,000 BTU mini-split heat pump · CASSETTE-single

ROVSUN TMSC-18HA2/I2XI20B-O

Below average cooling and heating efficiency for a 15,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #48 of 62 15,000 BTU mini-splits for cooling efficiency, and costs about $504 a year to run in a mixed climate like Atlanta.

SEER2: 20.5 Cooling efficiency over a season
Below average · beats 24%
HSPF2: 8.5 Heating efficiency over a season
Below average · beats 2%
EER2: 11.0 Cooling efficiency on a 95°F day
Below average · beats 9%
Heat at 5°F: 13,200 BTU/h73% of its 47°F output
Below average · beats 9%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,200 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

Cooling cost matters most - its SEER2 is below average for mini-splits.
You mainly need heat - its HSPF2 is below average for mini-splits.

Calculate my running cost

Details

Specifications15,000 BTU, R-454B

General
Brand	ROVSUN
Outdoor unit model	TMSC-18HA2/I2XI20B-O
Series	CASSETTE-single
Type	Mini-split heat pump
Nominal size	15,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	August 13, 2025
Last certified	January 14, 2026
Cooling
SEER2Seasonal efficiency, higher is better	20.5 (range 20.5)
EER2Efficiency at 95°F outdoors	11.0
Cooling capacity	16,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.5
Capacity at 47°F	18,000 BTU/h
Capacity at 17°F	14,500 BTU/h
Capacity at 5°F	13,200 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.80
ENERGY STAR cold climate	Yes

Heating output as it gets colder73% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with RVC-12/I-D 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.
RVC-12/I-D Rovsun · cold climate	20.5	11.0	8.5	13,200	218029843
RVC-O9/I-D Rovsun · cold climate	20.5	11.0	8.5	13,200	218029842

Yearly running cost in 10 large cities$371-$1,269

Phoenix, AZ$496/yr
Miami, FL$371/yr
Houston, TX$446/yr
Atlanta, GA$504/yr
Los Angeles, CA$502/yr
New York, NY$1,269/yr
Chicago, IL$1,043/yr
Denver, CO$877/yr
Seattle, WA$547/yr
Minneapolis, MN$1,090/yr

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

Questions5

What is the SEER2 rating of the ROVSUN TMSC-18HA2/I2XI20B-O?: The ROVSUN TMSC-18HA2/I2XI20B-O is rated at up to 20.5 SEER2 and 11.0 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the ROVSUN TMSC-18HA2/I2XI20B-O good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,200 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.
How much does the ROVSUN TMSC-18HA2/I2XI20B-O cost to run per year?: At its rated efficiency it costs about $371-$1,269 a year in electricity in large U.S. cities, depending on climate and local rates - for example $496 in Phoenix and $1,090 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Which indoor units work with the ROVSUN TMSC-18HA2/I2XI20B-O?: ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use Rovsun RVC-12/I-D, Rovsun RVC-O9/I-D.
What refrigerant does the ROVSUN TMSC-18HA2/I2XI20B-O use?: It uses R-454B.

Running cost and savings

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

Heat pump $512/yrYou save $346/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 ROVSUN TMSC-18HA2/I2XI20B-O

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: $512
Current system, per year: $858
You save per year: $346
Payback: 17.4 years
Net after 10 years: -$2,542

Cooling $275Heating $237Electricity used: 3,199 kWhSaved vs. a minimum-efficiency heat pump: $151

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 15,000 BTU models

Star Air Kontrol SAK-18-CC/220V20.5 SEER2 · 10.5 HSPF2
Fujitsu AOU15RLFF · cold climate20.3 SEER2 · 10.7 HSPF2
Mitsubishi Electric SUZ-CA15NLH20.6 SEER2 · 10.3 HSPF2
Fujitsu AOU15RLFFH · cold climate20.3 SEER2 · 10.5 HSPF2
Mitsubishi Electric SUZ-KA15NAH220.7 SEER2 · 9.6 HSPF2
Mitsubishi Electric MUZ-HM15NA20.0 SEER2 · 10.0 HSPF2
Mitsubishi Electric SUZ-KA15NA220.7 SEER2 · 10.7 HSPF2
Samsung AR60H15C1JWX20.0 SEER2 · 10.0 HSPF2

See all 62 15,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of January 14, 2026. How we use the data.