HVAC Rated

12,000 BTU mini-split heat pump · DIY Series

MRCOOL DIYHH-12-HP-C-230D25-O

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

Ranks #203 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $292 a year to run in a mixed climate like Atlanta.

SEER2
23.5 Cooling efficiency over a season
Very good · beats 70%
HSPF2
10.8 Heating efficiency over a season
Very good · beats 71%
EER2
12.8 Cooling efficiency on a 95°F day
Average · beats 56%
Heat at 5°F
11,500 BTU/h92% of its 47°F output
Average · beats 67%

A good fit if…

  • You want low cooling bills - its SEER2 beats 70% of mini-splits.
  • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 11,500 BTU/h at 5°F.
  • It will heat most of the year - its HSPF2 beats 71% 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
BrandMRCOOL
Also sold asMDV
Outdoor unit modelDIYHH-12-HP-C-230D25-O
SeriesDIY Series
TypeMini-split heat pump
Nominal size12,000 BTU
CompressorVariable-speed units run longer at low powerContinuously variable
RefrigerantR-454B
Connected (smart) capableNo
On the market sinceOctober 25, 2024
Last certifiedMarch 4, 2025
Cooling
SEER2Seasonal efficiency, higher is better23.5 (range 22.2-23.5)
EER2Efficiency at 95°F outdoors12.5-12.8
Cooling capacity12,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better10.0-10.8
Capacity at 47°F12,000-12,500 BTU/h
Capacity at 17°F8,900-11,900 BTU/h
Capacity at 5°F11,000-11,500 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater1.80-2.10
ENERGY STAR cold climateYes
Heating output as it gets colder92% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with DIY-12-HP-WMAH-230D25-O 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 unitSEER2EER2HSPF2Heat @5°FAHRI ref.
DIY-12-HP-WMAH-230D25-O · cold climate23.512.810.011,000216032549
DIYCASSETTE12HP-230D25-O · cold climate22.212.510.811,500216032550
Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the MRCOOL DIYHH-12-HP-C-230D25-O: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

  • MDV MOX330-12HFPN10-M1X
Yearly running cost in 10 large cities$241-$714

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 DIYHH-12-HP-C-230D25-O?
The MRCOOL DIYHH-12-HP-C-230D25-O is rated at up to 23.5 SEER2 and 12.8 EER2 for cooling and up to 10.8 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 2 certified matchups SEER2 ranges from 22.2-23.5.
Is the MRCOOL DIYHH-12-HP-C-230D25-O good for cold climates?
Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,500 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
How much does the MRCOOL DIYHH-12-HP-C-230D25-O cost to run per year?
At its rated efficiency it costs about $241-$714 a year in electricity in large U.S. cities, depending on climate and local rates - for example $307 in Phoenix and $604 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the MRCOOL DIYHH-12-HP-C-230D25-O the same as the MDV MOX330-12HFPN10-M1X?
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 DIYHH-12-HP-C-230D25-O?
ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use DIY-12-HP-WMAH-230D25-O, DIYCASSETTE12HP-230D25-O.
What refrigerant does the MRCOOL DIYHH-12-HP-C-230D25-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 $309/yrYou save $318/yrSee details ↓
1. Where you live
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.

2. The heat pump MRCOOL DIYHH-12-HP-C-230D25-O
3. What it replaces
4. Price replace the example with your quote
Heat pump, per year
$309
Current system, per year
$627
You save per year
$318
Payback
14.2 years
Net after 10 years
-$1,324

Cooling $180Heating $130Electricity used: 1,934 kWhSaved vs. a minimum-efficiency heat pump: $173

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.

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Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 4, 2025. How we use the data.