What is the SEER2 rating of the MRCOOL O-HH-12-HP-C-230C-O?

The MRCOOL O-HH-12-HP-C-230C-O is rated at up to 25.4 SEER2 and 13.4 EER2 for cooling and up to 11.6 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 20.0-25.4.

Is the MRCOOL O-HH-12-HP-C-230C-O good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,800 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.

How much does the MRCOOL O-HH-12-HP-C-230C-O cost to run per year?

At its rated efficiency it costs about $223-$642 a year in electricity in large U.S. cities, depending on climate and local rates - for example $281 in Phoenix and $541 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the MRCOOL O-HH-12-HP-C-230C-O the same as the MRCOOL O-ES-12-HP-C-230C-O1?

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 MRCOOL O-HH-12-HP-C-230C-O?

ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use O-12-HP-WMAH-230C-O, CASSETTE12HP-230C-O, DUCT-12HP-230B-O.

12,000 BTU mini-split heat pump · O-HH Series

MRCOOL O-HH-12-HP-C-230C-O

Very good cooling and heating efficiency for a 12,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #94 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $264 a year to run in a mixed climate like Atlanta.

SEER2: 25.4 Cooling efficiency over a season
Very good · beats 86%
HSPF2: 11.6 Heating efficiency over a season
Very good · beats 86%
EER2: 13.4 Cooling efficiency on a 95°F day
Very good · beats 72%
Heat at 5°F: 11,800 BTU/h96% of its 47°F output
Average · beats 48%

A good fit if…

You want low cooling bills - its SEER2 beats 86% of mini-splits.
Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 11,800 BTU/h at 5°F.
It will heat most of the year - its HSPF2 beats 86% of mini-splits.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

Nothing stands out - its ratings have no weak spot for its class.

Calculate my running cost

Details

Specifications12,000 BTU, R-454B

General
Brand	MRCOOL
Outdoor unit model	O-HH-12-HP-C-230C-O
Series	O-HH Series
Type	Mini-split heat pump
Nominal size	12,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	October 25, 2024
Last certified	May 6, 2026
Cooling
SEER2Seasonal efficiency, higher is better	25.4 (range 20.0-25.4)
EER2Efficiency at 95°F outdoors	12.0-13.4
Cooling capacity	12,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	10.0-11.6
Capacity at 47°F	12,000-12,500 BTU/h
Capacity at 17°F	9,600-12,000 BTU/h
Capacity at 5°F	11,500-11,800 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.80-2.00
ENERGY STAR cold climate	Yes

Heating output as it gets colder96% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with O-12-HP-WMAH-230C-O at the standard test temperatures, in BTU/h:

Certified matchups3 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.
O-12-HP-WMAH-230C-O · cold climate	25.4	13.4	10.5	11,500	216032560
CASSETTE12HP-230C-O · cold climate	22.2	12.5	11.6	11,500	216032561
DUCT-12HP-230B-O · cold climate	20.0	12.0	10.0	11,800	216032562

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the MRCOOL O-HH-12-HP-C-230C-O: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

MRCOOL O-ES-12-HP-C-230C-O1

Yearly running cost in 10 large cities$223-$642

Phoenix, AZ$281/yr
Miami, FL$223/yr
Houston, TX$252/yr
Atlanta, GA$264/yr
Los Angeles, CA$259/yr
New York, NY$642/yr
Chicago, IL$523/yr
Denver, CO$437/yr
Seattle, WA$270/yr
Minneapolis, MN$541/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 MRCOOL O-HH-12-HP-C-230C-O?: The MRCOOL O-HH-12-HP-C-230C-O is rated at up to 25.4 SEER2 and 13.4 EER2 for cooling and up to 11.6 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 20.0-25.4.
Is the MRCOOL O-HH-12-HP-C-230C-O good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,800 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
How much does the MRCOOL O-HH-12-HP-C-230C-O cost to run per year?: At its rated efficiency it costs about $223-$642 a year in electricity in large U.S. cities, depending on climate and local rates - for example $281 in Phoenix and $541 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the MRCOOL O-HH-12-HP-C-230C-O the same as the MRCOOL O-ES-12-HP-C-230C-O1?: 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 MRCOOL O-HH-12-HP-C-230C-O?: ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use O-12-HP-WMAH-230C-O, CASSETTE12HP-230C-O, DUCT-12HP-230B-O.
What refrigerant does the MRCOOL O-HH-12-HP-C-230C-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 $282/yrYou save $337/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 MRCOOL O-HH-12-HP-C-230C-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: $282
Current system, per year: $619
You save per year: $337
Payback: 13.4 years
Net after 10 years: -$1,134

Cooling $166Heating $116Electricity used: 1,764 kWhSaved vs. a minimum-efficiency heat pump: $192

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 12,000 BTU models

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NOVAIR LEA12SZ36-O · cold climate25.4 SEER2 · 11.6 HSPF2
Midea MO1HS-H12B-2A · cold climate25.4 SEER2 · 11.6 HSPF2
Stelpro SEPB-H12A-O · cold climate25.4 SEER2 · 11.6 HSPF2
DIRECT AIR DIRM4-12HXPRO28-1Z · cold climate25.4 SEER2 · 11.6 HSPF2
Continental CDHAS26BA-12-O · cold climate25.4 SEER2 · 10.5 HSPF2
Cooper&Hunter CH-RHP12-230VO · cold climate25.4 SEER2 · 11.6 HSPF2
MOOVAIR MSHMA12C2AN · cold climate25.4 SEER2 · 10.5 HSPF2

See all 394 12,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of May 6, 2026. How we use the data.