What is the SEER2 rating of the Lennox MMLD012S6S-1P?

The Lennox MMLD012S6S-1P is rated at up to 22.0 SEER2 and 12.6 EER2 for cooling and up to 10.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 18.6-22.0.

Is the Lennox MMLD012S6S-1P good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,200 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.

How much does the Lennox MMLD012S6S-1P cost to run per year?

At its rated efficiency it costs about $258-$819 a year in electricity in large U.S. cities, depending on climate and local rates - for example $336 in Phoenix and $698 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the Lennox MMLD012S6S-1P the same as the Samsung AC012DXSCCG?

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 Lennox MMLD012S6S-1P?

ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use LENNOX M22D012S6-1P, LENNOX M1WD012S6-1P, LENNOX MFMD012S6-1P.

12,000 BTU mini-split heat pump · 1-Way Cassette (WindFree™) Premium (CAC)

Lennox MMLD012S6S-1P

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

Ranks #294 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $330 a year to run in a mixed climate like Atlanta.

SEER2: 22.0 Cooling efficiency over a season
Average · beats 48%
HSPF2: 10.4 Heating efficiency over a season
Average · beats 57%
EER2: 12.6 Cooling efficiency on a 95°F day
Average · beats 52%
Heat at 5°F: 11,200 BTU/h80% of its 47°F output
Below average · beats 9%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 11,200 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

Specifications12,000 BTU, R-32

General
Brand	Lennox
Also sold as	Samsung
Outdoor unit model	MMLD012S6S-1P
Series	1-Way Cassette (WindFree™) Premium (CAC)
Type	Mini-split heat pump
Nominal size	12,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-32
Connected (smart) capable	No
On the market since	December 11, 2024
Last certified	May 13, 2026
Cooling
SEER2Seasonal efficiency, higher is better	22.0 (range 18.6-22.0)
EER2Efficiency at 95°F outdoors	11.7-12.6
Cooling capacity	10,200-12,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	9.5-10.4
Capacity at 47°F	13,000-14,000 BTU/h
Capacity at 17°F	7,600-10,800 BTU/h
Capacity at 5°F	10,400-11,200 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.80
ENERGY STAR cold climate	Yes

Heating output as it gets colder80% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with M22D012S6-1P 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 unit	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
M22D012S6-1P LENNOX · cold climate	22.0	12.6	10.4	11,200	216581327
M1WD012S6-1P LENNOX · cold climate	21.0	12.0	9.5	11,200	216581321
MFMD012S6-1P LENNOX · cold climate	21.0	12.2	9.5	10,400	216581329
MMDD012S6-1P LENNOX · cold climate	19.6	11.8	9.5	11,200	216581323
MDDD012S6-1P LENNOX · cold climate	18.6	11.7	9.5	11,200	216581325

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the Lennox MMLD012S6S-1P: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

Samsung AC012DXSCCG

Yearly running cost in 10 large cities$258-$819

Phoenix, AZ$336/yr
Miami, FL$258/yr
Houston, TX$302/yr
Atlanta, GA$330/yr
Los Angeles, CA$327/yr
New York, NY$819/yr
Chicago, IL$670/yr
Denver, CO$562/yr
Seattle, WA$349/yr
Minneapolis, MN$698/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 Lennox MMLD012S6S-1P?: The Lennox MMLD012S6S-1P is rated at up to 22.0 SEER2 and 12.6 EER2 for cooling and up to 10.4 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 5 certified matchups SEER2 ranges from 18.6-22.0.
Is the Lennox MMLD012S6S-1P good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 11,200 BTU/h at 5°F with a COP of 1.80, so it is still 1.8 times as efficient as electric resistance heat at that temperature.
How much does the Lennox MMLD012S6S-1P cost to run per year?: At its rated efficiency it costs about $258-$819 a year in electricity in large U.S. cities, depending on climate and local rates - for example $336 in Phoenix and $698 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the Lennox MMLD012S6S-1P the same as the Samsung AC012DXSCCG?: 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 Lennox MMLD012S6S-1P?: ENERGY STAR lists 5 certified combinations for this outdoor unit. The highest-rated ones use LENNOX M22D012S6-1P, LENNOX M1WD012S6-1P, LENNOX MFMD012S6-1P.
What refrigerant does the Lennox MMLD012S6S-1P 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 $343/yrYou save $309/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 Lennox MMLD012S6S-1P

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: $343
Current system, per year: $651
You save per year: $309
Payback: 14.6 years
Net after 10 years: -$1,413

Cooling $192Heating $151Electricity used: 2,142 kWhSaved vs. a minimum-efficiency heat pump: $162

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

Mitsubishi Electric NTXSKS12A112A22.0 SEER2 · 10.5 HSPF2
Star Air Kontrol SAK-12-OC/220V22.0 SEER2 · 9.8 HSPF2
Innovair QOS12H2BH0A · cold climate22.0 SEER2 · 10.5 HSPF2
AUX AFEB12HP115V1CO · cold climate22.0 SEER2 · 9.5 HSPF2
Hisense AUW-12U3TS1 · cold climate22.0 SEER2 · 10.5 HSPF2
AUX AFEB12HP230V1CO · cold climate22.0 SEER2 · 9.5 HSPF2
Guardian UPC12CN23STG1 · cold climate22.0 SEER2 · 10.5 HSPF2
AUX ASW-H12C5C2/P*R3DI-C5 · cold climate22.0 SEER2 · 9.5 HSPF2

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

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