What is the SEER2 rating of the AUX AH36LCA2DI-18US?

The AUX AH36LCA2DI-18US is rated at up to 18.0 SEER2 and 10.1 EER2 for cooling and up to 8.6 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the AUX AH36LCA2DI-18US good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 23,800 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.

How much does the AUX AH36LCA2DI-18US cost to run per year?

At its rated efficiency it costs about $879-$2,480 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,102 in Phoenix and $2,086 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the AUX AH36LCA2DI-18US the same as the Guardian GRC36CN23STG1?

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 AUX AH36LCA2DI-18US?

ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses AWH36LCA2DI-18US.

36,000 BTU mini-split heat pump · C-Series

AUX AH36LCA2DI-18US

Below average cooling and heating efficiency for a 36,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #196 of 205 36,000 BTU mini-splits for cooling efficiency, and costs about $1,025 a year to run in a mixed climate like Atlanta.

SEER2: 18.0 Cooling efficiency over a season
Below average · beats 4%
HSPF2: 8.6 Heating efficiency over a season
Below average · beats 4%
EER2: 10.1 Cooling efficiency on a 95°F day
Below average · beats 5%
Heat at 5°F: 23,800 BTU/h70% of its 47°F output
Average · beats 48%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 23,800 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

Specifications36,000 BTU, R-32

General
Brand	AUX
Also sold as	Guardian
Outdoor unit model	AH36LCA2DI-18US
Series	C-Series
Type	Mini-split heat pump
Nominal size	36,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-32
Connected (smart) capable	No
On the market since	February 28, 2026
Last certified	March 24, 2026
Cooling
SEER2Seasonal efficiency, higher is better	18.0 (range 18.0)
EER2Efficiency at 95°F outdoors	10.1
Cooling capacity	33,600 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.6
Capacity at 47°F	34,000 BTU/h
Capacity at 17°F	23,600 BTU/h
Capacity at 5°F	23,800 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	2.00
ENERGY STAR cold climate	Yes

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 AWH36LCA2DI-18US 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 unit	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
AWH36LCA2DI-18US · cold climate	18.0	10.1	8.6	23,800	218080131

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the AUX AH36LCA2DI-18US: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

Guardian GRC36CN23STG1

Yearly running cost in 10 large cities$879-$2,480

Phoenix, AZ$1,102/yr
Miami, FL$879/yr
Houston, TX$988/yr
Atlanta, GA$1,025/yr
Los Angeles, CA$1,003/yr
New York, NY$2,480/yr
Chicago, IL$2,019/yr
Denver, CO$1,684/yr
Seattle, WA$1,038/yr
Minneapolis, MN$2,086/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 AUX AH36LCA2DI-18US?: The AUX AH36LCA2DI-18US is rated at up to 18.0 SEER2 and 10.1 EER2 for cooling and up to 8.6 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the AUX AH36LCA2DI-18US good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 23,800 BTU/h at 5°F with a COP of 2.00, so it is still 2.0 times as efficient as electric resistance heat at that temperature.
How much does the AUX AH36LCA2DI-18US cost to run per year?: At its rated efficiency it costs about $879-$2,480 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,102 in Phoenix and $2,086 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the AUX AH36LCA2DI-18US the same as the Guardian GRC36CN23STG1?: 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 AUX AH36LCA2DI-18US?: ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses AWH36LCA2DI-18US.
What refrigerant does the AUX AH36LCA2DI-18US 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 $1,102/yrYou save $637/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 AUX AH36LCA2DI-18US

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: $1,102
Current system, per year: $1,739
You save per year: $637
Payback: 19.6 years
Net after 10 years: -$6,134

Cooling $657Heating $445Electricity used: 6,890 kWhSaved vs. a minimum-efficiency heat pump: $232

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 36,000 BTU models

Mitsubishi Electric RUZ-AK36NL · cold climate18.2 SEER2 · 8.6 HSPF2
Lennox VPC036H4M-3PS18.4 SEER2 · 9.0 HSPF2
Trane / Mitsubishi Electric TRUZH0361KA · cold climate17.6 SEER2 · 9.3 HSPF2
Carrier 37MTRAQ36EA3 · cold climate18.8 SEER2 · 8.5 HSPF2
Fujitsu AOUG36LMAS1 · cold climate17.1 SEER2 · 8.8 HSPF2
Arcoaire D5CMTAH36EAK · cold climate18.8 SEER2 · 8.5 HSPF2
Mitsubishi Electric RUZ-AK36NLHZ · cold climate17.0 SEER2 · 8.5 HSPF2
ComfortStar C32-MZ-4 · cold climate19.0 SEER2 · 9.0 HSPF2

See all 205 36,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 24, 2026. How we use the data.