HVAC Rated
    Menu

      9,000 BTU mini-split heat pump · 38 Series

      Trane 4TXK3809B10NU

      Excellent cooling efficiency and very good heating efficiency for a 9,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #88 of 395 9,000 BTU mini-splits for cooling efficiency, and costs about $201 a year to run in a mixed climate like Atlanta.

      SEER2
      27.0 Cooling efficiency over a season
      Excellent · beats 94%
      HSPF2
      11.0 Heating efficiency over a season
      Very good · beats 75%
      EER2
      16.6 Cooling efficiency on a 95°F day
      Excellent · beats 98%
      Heat at 5°F
      13,000 BTU/h144% of its 47°F output
      Below average · beats 31%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 94% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 13,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 75% of mini-splits.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications9,000 BTU, R-410A
      General
      BrandTrane
      Also sold asAmerican Standard, ACD
      Outdoor unit model4TXK3809B10NU
      Series38 Series
      TypeMini-split heat pump
      Nominal size9,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceJanuary 1, 2023
      Last certifiedJuly 25, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better27.0 (range 27.0)
      EER2Efficiency at 95°F outdoors16.6
      Cooling capacity9,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better11.0
      Capacity at 47°F9,000 BTU/h
      Capacity at 17°F8,200 BTU/h
      Capacity at 5°F13,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.91
      ENERGY STAR cold climateYes
      Heating output as it gets colder144% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 4MXW3809B10NU 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.
      4MXW3809B10NU TRANE · cold climate27.016.611.013,000204340354
      4MXW3809B10NU AMERICAN STANDARD · cold climate27.016.611.013,000204340355
      Same unit, other model numbers1

      These model numbers have exactly the same certified ratings and matchups as the Trane 4TXK3809B10NU: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      • ACD UHD09KCH38SB-O
      Yearly running cost in 10 large cities$158-$498

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

      Questions6
      What is the SEER2 rating of the Trane 4TXK3809B10NU?
      The Trane 4TXK3809B10NU is rated at up to 27.0 SEER2 and 16.6 EER2 for cooling and up to 11.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Trane 4TXK3809B10NU good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 13,000 BTU/h at 5°F with a COP of 1.91, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the Trane 4TXK3809B10NU cost to run per year?
      At its rated efficiency it costs about $158-$498 a year in electricity in large U.S. cities, depending on climate and local rates - for example $205 in Phoenix and $424 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the Trane 4TXK3809B10NU the same as the ACD UHD09KCH38SB-O?
      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 Trane 4TXK3809B10NU?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use TRANE 4MXW3809B10NU, AMERICAN STANDARD 4MXW3809B10NU.
      What refrigerant does the Trane 4TXK3809B10NU 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 $209/yrYou save $255/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 Trane 4TXK3809B10NU
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $209
      Current system, per year
      $464
      You save per year
      $255
      Payback
      13.7 years
      Net after 10 years
      -$949

      Cooling $117Heating $92Electricity used: 1,306 kWhSaved vs. a minimum-efficiency heat pump: $147

      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 9,000 BTU models

      See all 395 9,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of July 25, 2025. How we use the data.