What is the SEER2 rating of the Trane 4TXK3812A10NU?

The Trane 4TXK3812A10NU is rated at up to 24.0 SEER2 and 14.0 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the Trane 4TXK3812A10NU good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 12,000 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 4TXK3812A10NU cost to run per year?

At its rated efficiency it costs about $238-$853 a year in electricity in large U.S. cities, depending on climate and local rates - for example $324 in Phoenix and $736 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the Trane 4TXK3812A10NU the same as the ACD UHD12KCH31S-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 4TXK3812A10NU?

ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use TRANE 4MXW3812A10NU, AMERICAN STANDARD 4MXW3812A10NU.

What refrigerant does the Trane 4TXK3812A10NU 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.

12,000 BTU mini-split heat pump · 38 Series

Trane 4TXK3812A10NU

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

Ranks #199 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $336 a year to run in a mixed climate like Atlanta.

SEER2: 24.0 Cooling efficiency over a season
Very good · beats 75%
HSPF2: 8.5 Heating efficiency over a season
Below average · beats 2%
EER2: 14.0 Cooling efficiency on a 95°F day
Very good · beats 82%
Heat at 5°F: 12,000 BTU/h98% of its 47°F output
Below average · beats 31%

A good fit if…

You want low cooling bills - its SEER2 beats 75% of mini-splits.
Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 12,000 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

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

Specifications12,000 BTU, R-410A

General
Brand	Trane
Also sold as	American Standard, ACD
Outdoor unit model	4TXK3812A10NU
Series	38 Series
Type	Mini-split heat pump
Nominal size	12,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-410A
Connected (smart) capable	No
On the market since	January 1, 2023
Last certified	June 13, 2026
Cooling
SEER2Seasonal efficiency, higher is better	24.0 (range 24.0)
EER2Efficiency at 95°F outdoors	14.0
Cooling capacity	12,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.5
Capacity at 47°F	12,200 BTU/h
Capacity at 17°F	10,300 BTU/h
Capacity at 5°F	12,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.91
ENERGY STAR cold climate	Yes

Heating output as it gets colder98% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with 4MXW3812A10NU 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 unit	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
4MXW3812A10NU TRANE · cold climate	24.0	14.0	8.5	12,000	9150123
4MXW3812A10NU AMERICAN STANDARD · cold climate	24.0	14.0	8.5	12,000	9150124

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the Trane 4TXK3812A10NU: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

ACD UHD12KCH31S-O

Yearly running cost in 10 large cities$238-$853

Phoenix, AZ$324/yr
Miami, FL$238/yr
Houston, TX$291/yr
Atlanta, GA$336/yr
Los Angeles, CA$336/yr
New York, NY$853/yr
Chicago, IL$702/yr
Denver, CO$592/yr
Seattle, WA$370/yr
Minneapolis, MN$736/yr

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 4TXK3812A10NU?: The Trane 4TXK3812A10NU is rated at up to 24.0 SEER2 and 14.0 EER2 for cooling and up to 8.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the Trane 4TXK3812A10NU good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 12,000 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 4TXK3812A10NU cost to run per year?: At its rated efficiency it costs about $238-$853 a year in electricity in large U.S. cities, depending on climate and local rates - for example $324 in Phoenix and $736 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the Trane 4TXK3812A10NU the same as the ACD UHD12KCH31S-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 4TXK3812A10NU?: ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use TRANE 4MXW3812A10NU, AMERICAN STANDARD 4MXW3812A10NU.
What refrigerant does the Trane 4TXK3812A10NU 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 $337/yrYou save $285/yrSee details ↓

1. Where you live

StateCityElectricity ¢ per kWh

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.

Cooling hours full-load hours per yearHeating hours full-load hours per year

2. The heat pump Trane 4TXK3812A10NU

Find a model (fills in the ratings below)

SEER2 cooling efficiencyHSPF2 heating efficiencyCooling capacity BTU/hHeating capacity BTU/h

3. What it replaces

Current heatingFurnace efficiency (AFUE %)Gas price, $/thermCurrent coolingOld AC rating SEER2 (10 ≈ 15+ years old)

4. Price replace the example with your quote

Installed price, $Rebates and incentives, $ utility, state

Heat pump, per year: $337
Current system, per year: $622
You save per year: $285
Payback: 15.8 years
Net after 10 years: -$1,647

Cooling $176Heating $161Electricity used: 2,105 kWhSaved vs. a minimum-efficiency heat pump: $141

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 12,000 BTU models

Blueridge BMKH1231/O · cold climate24.0 SEER2 · 8.5 HSPF2
Fujitsu AOUH12KUAS1 · cold climate23.7 SEER2 · 11.5 HSPF2
Samsung AR12DXFAMWKX24.0 SEER2 · 9.0 HSPF2
LBG Products LBHB12DVWO · cold climate23.6 SEER2 · 10.5 HSPF2
Lennox MWHD012S6S-1P24.0 SEER2 · 9.0 HSPF2
AC Pro AOX330-12HFN1-MW5W · cold climate23.6 SEER2 · 10.2 HSPF2
ECO AC EHH-O12KBA · cold climate24.0 SEER2 · 9.0 HSPF2
MRCOOL DIYHH-12-HP-C-230D25-O · cold climate23.5 SEER2 · 10.8 HSPF2

See all 394 12,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 13, 2026. How we use the data.