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      2.5-ton central heat pump · ML Series

      Mainline ML30HP230LMNTH-O

      Average cooling efficiency and excellent heating efficiency for a 2.5-ton central heat pump, and certified for cold climates.

      Ranks #65 of 199 2.5 ton central heat pumps for cooling efficiency, and costs about $812 a year to run in a mixed climate like Atlanta.

      SEER2
      17.5 Cooling efficiency over a season
      Average · beats 58%
      HSPF2
      10.8 Heating efficiency over a season
      Excellent · beats 98%
      EER2
      11.7 Cooling efficiency on a 95°F day
      Average · beats 43%
      Heat at 5°F
      33,200 BTU/h100% of its 47°F output
      Below average · beats 39%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 33,200 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 98% of central heat pumps.
      • You want steady temperatures and quiet running - the compressor varies its speed.
      • You want a choice of indoor units - 21 certified pairings.

      Think twice if…

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

      Calculate my running cost

      Details

      Specifications2.5 ton, R-454B
      General
      BrandMainline
      Outdoor unit modelML30HP230LMNTH-O
      SeriesML Series
      TypeCentral heat pump
      Nominal size2.5 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceMay 20, 2024
      Last certifiedAugust 20, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better17.5 (range 15.3-17.5)
      EER2Efficiency at 95°F outdoors10.0-12.0
      Cooling capacity29,000-30,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.3-10.8
      Capacity at 47°F30,000-34,000 BTU/h
      Capacity at 17°F23,200-25,000 BTU/h
      Capacity at 5°F30,400-33,200 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.80-2.00
      ENERGY STAR cold climateYes
      Heating output as it gets colder100% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with ML30HP230WMAHU-I at the standard test temperatures, in BTU/h:

      Certified matchups21 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.
      ML30HP230WMAHU-I · cold climate17.511.710.232,000217607198
      ML30HP230WMAHU-I · cold climate17.511.710.232,000216623414
      ML30HP230G3AHU-I · cold climate17.212.010.833,200217607184
      ML36HP230G3AHU-I · cold climate17.212.010.833,200217607190
      ML36HP230G3AHU-I · cold climate17.212.010.833,200216623406
      ML30HP230G3AHU-I · cold climate17.212.010.833,200216623400
      ML36HP230LMNTAHU-I · cold climate16.811.710.032,600217607222
      ML30HP230LMNTAHU-I · cold climate16.811.710.032,600217607175
      ML30HP230LMNTAHU-I · cold climate16.811.710.032,600215864312
      ML36HP230LMNTAHU-I · cold climate16.811.710.032,600216623442
      ML30HP230PCAHU-I · cold climate16.311.09.531,000217607204
      ML30HP230PCAHU-I · cold climate16.311.09.531,000216623421
      ML36HP230CC21-I · cold climate16.011.09.632,000217607215
      ML36HP230CC17-I · cold climate16.011.09.632,000217607213
      ML36HP230CC21-I · cold climate16.011.09.632,000216623434
      ML36HP230CC17-I · cold climate16.011.09.632,000216623432
      ML36HP230UC17-I · cold climate16.011.09.632,000217890344
      ML36HP230UC21-I · cold climate16.011.09.632,000217890346
      ML36HP230CC14-I · cold climate15.310.09.330,400217607212
      ML36HP230CC14-I · cold climate15.310.09.330,400216623431
      ML36HP230UC14-I · cold climate15.310.09.330,400217890342
      Yearly running cost in 10 large cities$760-$1,879

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

      Questions5
      What is the SEER2 rating of the Mainline ML30HP230LMNTH-O?
      The Mainline ML30HP230LMNTH-O is rated at up to 17.5 SEER2 and 11.7 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 21 certified matchups SEER2 ranges from 15.3-17.5.
      Is the Mainline ML30HP230LMNTH-O good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 33,200 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 Mainline ML30HP230LMNTH-O cost to run per year?
      At its rated efficiency it costs about $760-$1,879 a year in electricity in large U.S. cities, depending on climate and local rates - for example $951 in Phoenix and $1,541 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 Mainline ML30HP230LMNTH-O?
      ENERGY STAR lists 21 certified combinations for this outdoor unit. The highest-rated ones use ML30HP230WMAHU-I, ML30HP230G3AHU-I, ML36HP230G3AHU-I.
      What refrigerant does the Mainline ML30HP230LMNTH-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 $925/yrYou save $638/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 Mainline ML30HP230LMNTH-O
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $925
      Current system, per year
      $1,563
      You save per year
      $638
      Payback
      18.0 years
      Net after 10 years
      -$5,117

      Cooling $603Heating $321Electricity used: 5,781 kWhSaved vs. a minimum-efficiency heat pump: $276

      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 2.5 ton models

      See all 199 2.5 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of August 20, 2026. How we use the data.