What is the SEER2 rating of the Hisense AO-18U3T25U?

The Hisense AO-18U3T25U is rated at up to 21.0 SEER2 and 12.1 EER2 for cooling and up to 9.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the Hisense AO-18U3T25U good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 18,000 BTU/h at 5°F with a COP of 1.90, so it is still 1.9 times as efficient as electric resistance heat at that temperature.

How much does the Hisense AO-18U3T25U cost to run per year?

At its rated efficiency it costs about $404-$1,174 a year in electricity in large U.S. cities, depending on climate and local rates - for example $511 in Phoenix and $991 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 Hisense AO-18U3T25U?

ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use HISENSE ASU-18U3THB25U, HISENSE ASU-18U3THB25U-B, HISENSE ASU-18U3THB25U-S.

18,000 BTU mini-split heat pump · Hi-ULTRA

Hisense AO-18U3T25U

Below average cooling and heating efficiency for a 18,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #358 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $482 a year to run in a mixed climate like Atlanta.

SEER2: 21.0 Cooling efficiency over a season
Below average · beats 30%
HSPF2: 9.5 Heating efficiency over a season
Below average · beats 24%
EER2: 12.1 Cooling efficiency on a 95°F day
Below average · beats 31%
Heat at 5°F: 18,000 BTU/h100% of its 47°F output
Below average · beats 27%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 18,000 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

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-454B

General
Brand	Hisense
Outdoor unit model	AO-18U3T25U
Series	Hi-ULTRA
Type	Mini-split heat pump
Nominal size	18,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	November 21, 2024
Last certified	July 6, 2026
Cooling
SEER2Seasonal efficiency, higher is better	21.0 (range 21.0)
EER2Efficiency at 95°F outdoors	12.1
Cooling capacity	18,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	9.5
Capacity at 47°F	18,000 BTU/h
Capacity at 17°F	18,000 BTU/h
Capacity at 5°F	18,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.90
ENERGY STAR cold climate	Yes

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 ASU-18U3THB25U at the standard test temperatures, in BTU/h:

Certified matchups3 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.
ASU-18U3THB25U HISENSE · cold climate	21.0	12.1	9.5	18,000	216370236
ASU-18U3THB25U-B HISENSE · cold climate	21.0	12.1	9.5	18,000	217080953
ASU-18U3THB25U-S HISENSE · cold climate	21.0	12.1	9.5	18,000	218621914

Yearly running cost in 10 large cities$404-$1,174

Phoenix, AZ$511/yr
Miami, FL$404/yr
Houston, TX$459/yr
Atlanta, GA$482/yr
Los Angeles, CA$473/yr
New York, NY$1,174/yr
Chicago, IL$957/yr
Denver, CO$799/yr
Seattle, WA$494/yr
Minneapolis, MN$991/yr

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

Questions5

What is the SEER2 rating of the Hisense AO-18U3T25U?: The Hisense AO-18U3T25U is rated at up to 21.0 SEER2 and 12.1 EER2 for cooling and up to 9.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the Hisense AO-18U3T25U good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 18,000 BTU/h at 5°F with a COP of 1.90, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
How much does the Hisense AO-18U3T25U cost to run per year?: At its rated efficiency it costs about $404-$1,174 a year in electricity in large U.S. cities, depending on climate and local rates - for example $511 in Phoenix and $991 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 Hisense AO-18U3T25U?: ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use HISENSE ASU-18U3THB25U, HISENSE ASU-18U3THB25U-B, HISENSE ASU-18U3THB25U-S.
What refrigerant does the Hisense AO-18U3T25U 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 $514/yrYou save $414/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 Hisense AO-18U3T25U

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: $514
Current system, per year: $928
You save per year: $414
Payback: 16.9 years
Net after 10 years: -$2,858

Cooling $302Heating $212Electricity used: 3,212 kWhSaved vs. a minimum-efficiency heat pump: $198

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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PerfectAire 3PAMSHHQC18-MZO2 · cold climate21.0 SEER2 · 9.5 HSPF2
GE Appliances ASH118PRDB · cold climate21.0 SEER2 · 9.6 HSPF2
Daikin RXTH18AVJU · cold climate21.0 SEER2 · 9.4 HSPF2
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See all 465 18,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of July 6, 2026. How we use the data.