What is the SEER2 rating of the MRCOOL DIY-18-HP-C-230D25-O?

The MRCOOL DIY-18-HP-C-230D25-O is rated at up to 22.5 SEER2 and 13.7 EER2 for cooling and up to 11.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 2 certified matchups SEER2 ranges from 21.4-22.5.

Is the MRCOOL DIY-18-HP-C-230D25-O good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,100 BTU/h at 5°F with a COP of 2.44, so it is still 2.4 times as efficient as electric resistance heat at that temperature.

How much does the MRCOOL DIY-18-HP-C-230D25-O cost to run per year?

At its rated efficiency it costs about $376-$992 a year in electricity in large U.S. cities, depending on climate and local rates - for example $461 in Phoenix and $827 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the MRCOOL DIY-18-HP-C-230D25-O the same as the MDV MOX430-18HFPN10-M1?

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 DIY-18-HP-C-230D25-O?

ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use DIY-18-HP-WMAH-230D25-O, DIYCASSETTE18HP-230D25-O.

18,000 BTU mini-split heat pump · DIY Series

MRCOOL DIY-18-HP-C-230D25-O

Average cooling efficiency and very good heating efficiency for a 18,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #176 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $416 a year to run in a mixed climate like Atlanta.

SEER2: 22.5 Cooling efficiency over a season
Average · beats 56%
HSPF2: 11.5 Heating efficiency over a season
Very good · beats 84%
EER2: 13.7 Cooling efficiency on a 95°F day
Very good · beats 78%
Heat at 5°F: 13,100 BTU/h71% of its 47°F output
Excellent · beats 96%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,100 BTU/h at 5°F.
It will heat most of the year - its HSPF2 beats 84% 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

Specifications18,000 BTU, R-454B

General
Brand	MRCOOL
Also sold as	MDV
Outdoor unit model	DIY-18-HP-C-230D25-O
Series	DIY Series
Type	Mini-split heat pump
Nominal size	18,000 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	March 4, 2025
Cooling
SEER2Seasonal efficiency, higher is better	22.5 (range 21.4-22.5)
EER2Efficiency at 95°F outdoors	12.5-13.7
Cooling capacity	18,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	11.5
Capacity at 47°F	18,000 BTU/h
Capacity at 17°F	13,300-13,400 BTU/h
Capacity at 5°F	12,800-13,100 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	2.32-2.44
ENERGY STAR cold climate	Yes

Heating output as it gets colder71% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with DIY-18-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 unit	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
DIY-18-HP-WMAH-230D25-O · cold climate	22.5	13.7	11.5	12,800	216032545
DIYCASSETTE18HP-230D25-O · cold climate	21.4	12.5	11.5	13,100	216032546

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the MRCOOL DIY-18-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 MOX430-18HFPN10-M1

Yearly running cost in 10 large cities$376-$992

Phoenix, AZ$461/yr
Miami, FL$376/yr
Houston, TX$413/yr
Atlanta, GA$416/yr
Los Angeles, CA$404/yr
New York, NY$992/yr
Chicago, IL$805/yr
Denver, CO$669/yr
Seattle, WA$411/yr
Minneapolis, MN$827/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 DIY-18-HP-C-230D25-O?: The MRCOOL DIY-18-HP-C-230D25-O is rated at up to 22.5 SEER2 and 13.7 EER2 for cooling and up to 11.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 2 certified matchups SEER2 ranges from 21.4-22.5.
Is the MRCOOL DIY-18-HP-C-230D25-O good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,100 BTU/h at 5°F with a COP of 2.44, so it is still 2.4 times as efficient as electric resistance heat at that temperature.
How much does the MRCOOL DIY-18-HP-C-230D25-O cost to run per year?: At its rated efficiency it costs about $376-$992 a year in electricity in large U.S. cities, depending on climate and local rates - for example $461 in Phoenix and $827 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the MRCOOL DIY-18-HP-C-230D25-O the same as the MDV MOX430-18HFPN10-M1?: 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 DIY-18-HP-C-230D25-O?: ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use DIY-18-HP-WMAH-230D25-O, DIYCASSETTE18HP-230D25-O.
What refrigerant does the MRCOOL DIY-18-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 $457/yrYou save $471/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 DIY-18-HP-C-230D25-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: $457
Current system, per year: $928
You save per year: $471
Payback: 14.9 years
Net after 10 years: -$2,288

Cooling $282Heating $175Electricity used: 2,856 kWhSaved vs. a minimum-efficiency heat pump: $255

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

InfinityLiving EZ-18ZPL-HP230B · cold climate22.5 SEER2 · 11.5 HSPF2
Panasonic CU-2Z18ABUC · cold climate22.5 SEER2 · 12.5 HSPF2
GE Appliances 2G18AD2BE · cold climate22.5 SEER2 · 10.5 HSPF2
Mitsubishi Electric MUZ-GX18NL · cold climate22.5 SEER2 · 10.3 HSPF2
Blueridge BMY18DIY22C22.7 SEER2 · 9.8 HSPF2
Mitsubishi Electric MUZ-GX18NLHZ · cold climate22.5 SEER2 · 10.0 HSPF2
1HVAC EZ-18ZPL-HP23022.7 SEER2 · 9.8 HSPF2
LG KUMXB181A22.5 SEER2 · 9.8 HSPF2

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

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