HVAC Rated
    Menu

      18,000 BTU mini-split heat pump · Q series

      COSTWAY FP10518US-12WH

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

      Ranks #364 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $485 a year to run in a mixed climate like Atlanta.

      SEER2
      21.0 Cooling efficiency over a season
      Below average · beats 30%
      HSPF2
      9.0 Heating efficiency over a season
      Below average · beats 10%
      EER2
      12.0 Cooling efficiency on a 95°F day
      Below average · beats 25%
      Heat at 5°F
      11,600 BTU/h66% of its 47°F output
      Very good · beats 75%

      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.

      Calculate my running cost

      Details

      Specifications18,000 BTU, R-32
      General
      BrandCOSTWAY
      Also sold asPremium Levella, ALBOTT, AUX
      Outdoor unit modelFP10518US-12WH
      SeriesQ series
      TypeMini-split heat pump
      Nominal size18,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-32
      Connected (smart) capableNo
      On the market sinceMarch 1, 2024
      Last certifiedMarch 20, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better21.0 (range 21.0)
      EER2Efficiency at 95°F outdoors12.0
      Cooling capacity17,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.0
      Capacity at 47°F17,700 BTU/h
      Capacity at 17°F14,300 BTU/h
      Capacity at 5°F11,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.17
      ENERGY STAR cold climateNo
      Heating output as it gets colder66% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with FP10518US-22WH at the standard test temperatures, in BTU/h:

      Certified matchups1 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.
      FP10518US-22WH21.012.09.011,600212528056
      Same unit, other model numbers6

      These model numbers have exactly the same certified ratings and matchups as the COSTWAY FP10518US-12WH: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$383-$1,199

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

      Questions6
      What is the SEER2 rating of the COSTWAY FP10518US-12WH?
      The COSTWAY FP10518US-12WH is rated at up to 21.0 SEER2 and 12.0 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the COSTWAY FP10518US-12WH 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 COSTWAY FP10518US-12WH cost to run per year?
      At its rated efficiency it costs about $383-$1,199 a year in electricity in large U.S. cities, depending on climate and local rates - for example $497 in Phoenix and $1,020 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the COSTWAY FP10518US-12WH the same as the COSTWAY FP10789US-12BK?
      Yes, as far as the certified ratings go. ENERGY STAR lists 7 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 COSTWAY FP10518US-12WH?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses FP10518US-22WH.
      What refrigerant does the COSTWAY FP10518US-12WH use?
      It uses 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 $505/yrYou save $383/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 COSTWAY FP10518US-12WH
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $505
      Current system, per year
      $888
      You save per year
      $383
      Payback
      17.0 years
      Net after 10 years
      -$2,672

      Cooling $285Heating $220Electricity used: 3,158 kWhSaved vs. a minimum-efficiency heat pump: $178

      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

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

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 20, 2025. How we use the data.