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

      MDV MOX330-18HFN1-MS0W

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

      Ranks #425 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $523 a year to run in a mixed climate like Atlanta.

      SEER2
      19.5 Cooling efficiency over a season
      Below average · beats 12%
      HSPF2
      9.1 Heating efficiency over a season
      Below average · beats 13%
      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
      BrandMDV
      Also sold asMidea, ECO-AIR, Alsetria
      Outdoor unit modelMOX330-18HFN1-MS0W
      SeriesMS Series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceOctober 31, 2022
      Last certifiedJune 25, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better19.5 (range 19.0-19.5)
      EER2Efficiency at 95°F outdoors11.0-11.2
      Cooling capacity18,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.7-9.1
      Capacity at 47°F18,000-18,800 BTU/h
      Capacity at 17°F11,400-11,600 BTU/h
      Capacity at 5°F11,700 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.06
      ENERGY STAR cold climateNo
      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 MSAG11C-18HRDN1-MS0W at the standard test temperatures, in BTU/h:

      Certified matchups5 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.
      MSAG11C-18HRDN1-MS0W19.511.08.711,700206369513
      MSAG11C-18HRDN1-MS0W MIDEA19.511.08.711,700212349510
      MSAG11C-18HRDN1-MS0W ECO-AIR19.511.08.711,700208121847
      MSAG11C-18HRDN1-MS0W Alsetria19.511.08.711,700208121884
      MSAEC-18HRDN1-MP0W19.011.29.1-206369507
      Yearly running cost in 10 large cities$436-$1,277

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

      Questions5
      What is the SEER2 rating of the MDV MOX330-18HFN1-MS0W?
      The MDV MOX330-18HFN1-MS0W is rated at up to 19.5 SEER2 and 11.0 EER2 for cooling and up to 9.1 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 19.0-19.5.
      Is the MDV MOX330-18HFN1-MS0W 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 MDV MOX330-18HFN1-MS0W cost to run per year?
      At its rated efficiency it costs about $436-$1,277 a year in electricity in large U.S. cities, depending on climate and local rates - for example $553 in Phoenix and $1,079 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 MDV MOX330-18HFN1-MS0W?
      ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use MSAG11C-18HRDN1-MS0W, MIDEA MSAG11C-18HRDN1-MS0W, ECO-AIR MSAG11C-18HRDN1-MS0W.
      What refrigerant does the MDV MOX330-18HFN1-MS0W 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 $556/yrYou save $385/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 MDV MOX330-18HFN1-MS0W
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $556
      Current system, per year
      $941
      You save per year
      $385
      Payback
      18.2 years
      Net after 10 years
      -$3,151

      Cooling $325Heating $231Electricity used: 3,477 kWhSaved vs. a minimum-efficiency heat pump: $168

      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 June 25, 2026. How we use the data.