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      12,000 BTU mini-split heat pump · LEA Series

      NOVAIR LEA12SZ26-O

      Very good cooling and heating efficiency for a 12,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #47 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $265 a year to run in a mixed climate like Atlanta.

      SEER2
      25.5 Cooling efficiency over a season
      Very good · beats 88%
      HSPF2
      11.5 Heating efficiency over a season
      Very good · beats 84%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Average · beats 62%
      Heat at 5°F
      8,900 BTU/h70% of its 47°F output
      Excellent · beats 97%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 88% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 8,900 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

      Specifications12,000 BTU, R-454B
      General
      BrandNOVAIR
      Outdoor unit modelLEA12SZ26-O
      SeriesLEA Series
      TypeMini-split heat pump
      Nominal size12,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceJuly 18, 2025
      Last certifiedMay 28, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better25.5 (range 19.0-25.5)
      EER2Efficiency at 95°F outdoors11.7-13.0
      Cooling capacity11,500-12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.2-11.5
      Capacity at 47°F12,000 BTU/h
      Capacity at 17°F8,500-10,400 BTU/h
      Capacity at 5°F8,400-8,900 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.25-2.50
      ENERGY STAR cold climateYes
      Heating output as it gets colder70% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 4LEA12USK-I 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.
      4LEA12USK-I · cold climate25.513.010.68,400217606295
      LEA12CONSK-I · cold climate24.612.711.08,900217606317
      3LEA12USK-I · cold climate23.112.211.58,600217606291
      LEA12CASS-I · cold climate21.112.510.48,400217606310
      LEA12DUCT-I · cold climate19.011.710.28,800217606314
      Yearly running cost in 10 large cities$222-$646

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

      Questions5
      What is the SEER2 rating of the NOVAIR LEA12SZ26-O?
      The NOVAIR LEA12SZ26-O is rated at up to 25.5 SEER2 and 13.0 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 5 certified matchups SEER2 ranges from 19.0-25.5.
      Is the NOVAIR LEA12SZ26-O good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 8,900 BTU/h at 5°F with a COP of 2.50, so it is still 2.5 times as efficient as electric resistance heat at that temperature.
      How much does the NOVAIR LEA12SZ26-O cost to run per year?
      At its rated efficiency it costs about $222-$646 a year in electricity in large U.S. cities, depending on climate and local rates - for example $281 in Phoenix and $545 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 NOVAIR LEA12SZ26-O?
      ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use 4LEA12USK-I, LEA12CONSK-I, 3LEA12USK-I.
      What refrigerant does the NOVAIR LEA12SZ26-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 $283/yrYou save $336/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 NOVAIR LEA12SZ26-O
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $283
      Current system, per year
      $619
      You save per year
      $336
      Payback
      13.4 years
      Net after 10 years
      -$1,138

      Cooling $166Heating $117Electricity used: 1,766 kWhSaved vs. a minimum-efficiency heat pump: $192

      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 May 28, 2026. How we use the data.