What is the SEER2 rating of the Mainline ML36HP230LMNT-O?

The Mainline ML36HP230LMNT-O is rated at up to 16.7 SEER2 and 10.2 EER2 for cooling and up to 9.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 6 certified matchups SEER2 ranges from 15.4-16.7.

Is the Mainline ML36HP230LMNT-O good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 29,200 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 Mainline ML36HP230LMNT-O cost to run per year?

At its rated efficiency it costs about $1,011-$2,551 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,225 in Phoenix and $2,115 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the Mainline ML36HP230LMNT-O the same as the 1HVAC ACIQ-36-EHPD?

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 Mainline ML36HP230LMNT-O?

ENERGY STAR lists 6 certified combinations for this outdoor unit. The highest-rated ones use ML36HP230WMAHU-I, ML36HP230LMNTAHU-I, ML36HP230PCAHU-I.

3-ton central heat pump · ML Series

Mainline ML36HP230LMNT-O

Average cooling and heating efficiency for a 3-ton central heat pump, and certified for cold climates.

Ranks #187 of 302 3 ton central heat pumps for cooling efficiency, and costs about $1,082 a year to run in a mixed climate like Atlanta.

SEER2: 16.7 Cooling efficiency over a season
Average · beats 43%
HSPF2: 9.3 Heating efficiency over a season
Average · beats 62%
EER2: 10.2 Cooling efficiency on a 95°F day
Below average · beats 15%
Heat at 5°F: 29,200 BTU/h79% of its 47°F output
Below average · beats 39%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 29,200 BTU/h at 5°F.
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

Specifications3 ton, R-454B

General
Brand	Mainline
Also sold as	1HVAC, ACIQ
Outdoor unit model	ML36HP230LMNT-O
Series	ML Series
Type	Central heat pump
Nominal size	3 ton
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	May 20, 2024
Last certified	August 19, 2026
Cooling
SEER2Seasonal efficiency, higher is better	16.7 (range 15.4-16.7)
EER2Efficiency at 95°F outdoors	9.2-10.2
Cooling capacity	36,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.7-9.3
Capacity at 47°F	36,000-37,000 BTU/h
Capacity at 17°F	24,600-27,000 BTU/h
Capacity at 5°F	27,000-29,200 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.86-2.00
ENERGY STAR cold climate	Yes

Heating output as it gets colder79% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with ML36HP230WMAHU-I at the standard test temperatures, in BTU/h:

Certified matchups6 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.
ML36HP230WMAHU-I · cold climate	16.7	10.2	9.3	29,200	217607195
ML36HP230WMAHU-I · cold climate	16.7	10.2	9.3	29,200	216623411
ML36HP230LMNTAHU-I · cold climate	16.1	10.0	8.7	27,000	217607170
ML36HP230LMNTAHU-I · cold climate	16.1	10.0	8.7	27,000	215864307
ML36HP230PCAHU-I · cold climate	15.4	9.2	8.7	28,400	217607201
ML36HP230PCAHU-I · cold climate	15.4	9.2	8.7	28,400	216623418

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the Mainline ML36HP230LMNT-O: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

1HVAC ACIQ-36-EHPD

Yearly running cost in 10 large cities$1,011-$2,551

Phoenix, AZ$1,225/yr
Miami, FL$1,011/yr
Houston, TX$1,097/yr
Atlanta, GA$1,082/yr
Los Angeles, CA$1,046/yr
New York, NY$2,551/yr
Chicago, IL$2,064/yr
Denver, CO$1,711/yr
Seattle, WA$1,047/yr
Minneapolis, MN$2,115/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 Mainline ML36HP230LMNT-O?: The Mainline ML36HP230LMNT-O is rated at up to 16.7 SEER2 and 10.2 EER2 for cooling and up to 9.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 6 certified matchups SEER2 ranges from 15.4-16.7.
Is the Mainline ML36HP230LMNT-O good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 29,200 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 Mainline ML36HP230LMNT-O cost to run per year?: At its rated efficiency it costs about $1,011-$2,551 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,225 in Phoenix and $2,115 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the Mainline ML36HP230LMNT-O the same as the 1HVAC ACIQ-36-EHPD?: 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 Mainline ML36HP230LMNT-O?: ENERGY STAR lists 6 certified combinations for this outdoor unit. The highest-rated ones use ML36HP230WMAHU-I, ML36HP230LMNTAHU-I, ML36HP230PCAHU-I.
What refrigerant does the Mainline ML36HP230LMNT-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 $1,204/yrYou save $668/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 Mainline ML36HP230LMNT-O

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: $1,204
Current system, per year: $1,873
You save per year: $668
Payback: 20.2 years
Net after 10 years: -$6,818

Cooling $759Heating $446Electricity used: 7,527 kWhSaved vs. a minimum-efficiency heat pump: $234

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 3 ton models

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Elios ESHEA36R2AN1 · cold climate16.7 SEER2 · 9.3 HSPF2
Midea MO1BE-H36B-2A · cold climate16.7 SEER2 · 9.3 HSPF2
DuraSTAR DRU1U36S2A · cold climate16.7 SEER2 · 9.3 HSPF2
MOOVAIR MSHEA36R2AN1 · cold climate16.7 SEER2 · 9.3 HSPF2
Day & Night D5CURAH36AAK · cold climate16.7 SEER2 · 9.3 HSPF2
MRCOOL MHP17L36P-**A16.6 SEER2 · 8.7 HSPF2

See all 302 3 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of August 19, 2026. How we use the data.