What is the SEER2 rating of the Lennox ML17XP1-042-230A?

The Lennox ML17XP1-042-230A is rated at up to 15.6 SEER2 and 13.0 EER2 for cooling and up to 8.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 206 certified matchups SEER2 ranges from 15.2-15.6.

Is the Lennox ML17XP1-042-230A good for cold climates?

It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 3.5-ton model.

How much does the Lennox ML17XP1-042-230A cost to run per year?

At its rated efficiency it costs about $1,240-$3,040 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,495 in Phoenix and $2,509 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 Lennox ML17XP1-042-230A?

ENERGY STAR lists 206 certified combinations for this outdoor unit. The highest-rated ones use CBA27UHE-042-230*+TDR, CBA38MV-042-230*+TDR, CRX35-48C-**-*+TDR.

What refrigerant does the Lennox ML17XP1-042-230A 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.

3.5-ton central heat pump · MERIT ML17XP1 Series

Lennox ML17XP1-042-230A

Below average cooling and heating efficiency for a 3.5-ton central heat pump, but not rated for cold climates.

Ranks #94 of 138 3.5 ton central heat pumps for cooling efficiency, and costs about $1,300 a year to run in a mixed climate like Atlanta.

SEER2: 15.6 Cooling efficiency over a season
Below average · beats 17%
HSPF2: 8.3 Heating efficiency over a season
Below average · beats 30%
EER2: 13.0 Cooling efficiency on a 95°F day
Very good · beats 89%
Heat at 5°F: 22,000 BTU/h55% of its 47°F output
Very good · beats 80%

A good fit if…

You want a choice of indoor units - 206 certified pairings.

Think twice if…

You often see nights below 0°F - it is not cold-climate certified.
Cooling cost matters most - its SEER2 is below average for central heat pumps.
You mainly need heat - its HSPF2 is below average for central heat pumps.
You want the newest refrigerant - it uses R-410A, which is being phased down.

Calculate my running cost

Details

Specifications3.5 ton, R-410A

General
Brand	Lennox
Outdoor unit model	ML17XP1-042-230A
Series	MERIT ML17XP1 Series
Type	Central heat pump
Nominal size	3.5 ton
CompressorVariable-speed units run longer at low power	Single stage
Refrigerant	R-410A
Connected (smart) capable	No
On the market since	January 10, 2022
Last certified	October 27, 2025
Cooling
SEER2Seasonal efficiency, higher is better	15.6 (range 15.2-15.6)
EER2Efficiency at 95°F outdoors	12.5-13.0
Cooling capacity	40,000-42,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	7.8-8.3
Capacity at 47°F	37,600-42,000 BTU/h
Capacity at 17°F	25,000-27,800 BTU/h
Capacity at 5°F	10,400-22,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	2.00-2.22
ENERGY STAR cold climate	No

Heating output as it gets colder55% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with CBA27UHE-042-230*+TDR at the standard test temperatures, in BTU/h:

Certified matchups206 indoor units

The same outdoor unit scores differently with each indoor unit and furnace. The 60 highest-rated of 206 are shown. Ask your installer for the AHRI reference number of the exact system you are quoted.

Indoor unit	Furnace	SEER2	EER2	HSPF2	Heat @5°F	AHRI ref.
CBA27UHE-042-230*+TDR	-	15.6	13.0	8.3	22,000	210049508
CBA38MV-042-230*+TDR	-	15.6	13.0	8.3	20,600	210049509
CRX35-48C-*-+TDR	ML180DF110E60C*	15.6	13.0	8.3	21,800	213258050
CK40DT-48C-0*+TDR	ML180DF110E60C*	15.6	13.0	8.3	21,800	214624297
CBK47UHET-042-230-0	-	15.6	13.0	8.3	22,000	214861207
CX35-49C+TDR	ML180UH110V60C*	15.6	13.0	7.8	19,900	210049579
C35-49C+TDR+TXV	ML180UH110V60C*	15.6	13.0	7.8	19,900	210049479
C35-49C+TDR+TXV	SL280UH100NV60C*	15.6	13.0	7.8	19,900	210049502
CX35-49C+TDR	SL280UH100NV60C*	15.6	13.0	7.8	19,900	210049596
C35-48C+TDR+TXV	SL280UH080NV60C*	15.6	13.0	7.8	19,700	210857167
C35-48C+TDR+TXV	SL280UH100NV60C*	15.6	13.0	7.8	19,700	210857170
C35-48C+TDR+TXV	ML180UH110V60C*	15.6	13.0	7.8	19,700	210857160
C35-48C+TDR+TXV	EL280UH110XE60C*	15.6	13.0	7.8	19,600	210857156
C35-48C+TDR+TXV	EL280UH110E48C*	15.6	13.0	7.8	19,600	210857154
C35-48C+TDR+TXV	EL280UH110E60C*	15.6	13.0	7.8	19,600	210857155
CHX35-42B-*-+TDR	EL280UH090E48B*	15.6	13.0	7.8	19,900	210869919
CHX35-42B-*-+TDR	EL280UH090XE48B*	15.6	13.0	7.8	19,900	210869920
CX35-48C+TDR	EL280UH110E60C*	15.6	13.0	7.8	19,600	210869935
CX35-48C+TDR	EL280UH110E48C*	15.6	13.0	7.8	19,600	210869934
CX35-48C+TDR	EL280UH110XE60C*	15.6	13.0	7.8	19,600	210869936
CX35-48C+TDR	ML180UH110V60C*	15.6	13.0	7.8	19,700	210869940
CX35-48C+TDR	SL280UH080NV60C*	15.6	13.0	7.8	19,700	210869947
CX35-48C+TDR	SL280UH100NV60C*	15.6	13.0	7.8	19,700	210869950
CK40CT-49C-0*+TDR	ML180UH110V60C*	15.6	13.0	7.8	19,900	214624398
CK40CT-49C-0*+TDR	SL280UH100NV60C*	15.6	13.0	7.8	19,900	214624413
CK40CT-48C-0*+TDR	EL280UH110E60C*	15.6	13.0	7.8	19,600	214624346
CK40CT-48C-0*+TDR	EL280UH110E48C*	15.6	13.0	7.8	19,600	214624345
CK40CT-48C-0*+TDR	EL280UH110XE60C*	15.6	13.0	7.8	19,600	214624347
CK40CT-48C-0*+TDR	ML180UH110V60C*	15.6	13.0	7.8	19,700	214624357
CK40CT-48C-0*+TDR	SL280UH080NV60C*	15.6	13.0	7.8	19,700	214624369
CK40CT-48C-0*+TDR	SL280UH100NV60C*	15.6	13.0	7.8	19,700	214624372
CK40HT-42B-0*+TDR	EL280UH090E48B*	15.6	13.0	7.8	19,900	214624160
CK40HT-42B-0*+TDR	EL280UH090XE48B*	15.6	13.0	7.8	19,900	214624161
CRX35-48C-*-+TDR	SL280DF110V60C*	15.4	13.0	8.3	22,000	213258053
CK40DT-48C-0*+TDR	SL280DF110V60C*	15.4	13.0	8.3	22,000	214624304
CBA25UHV-042-230-	-	15.4	13.0	8.1	20,200	210049505
CBK45UHVT-042-230-0	-	15.4	13.0	8.1	20,200	214861206
CHX35-42B-*-+TDR	ML180UH070V48B*	15.4	13.0	8.0	22,000	210869923
CHX35-42B-*-+TDR	SL280UH080NV48B*	15.4	13.0	8.0	20,200	210869925
CK40HT-42B-0*+TDR	ML180UH070V48B*	15.4	13.0	8.0	22,000	214624167
CK40HT-42B-0*+TDR	SL280UH080NV48B*	15.4	13.0	8.0	20,200	214624178
C35-49C+TDR+TXV	EL280UH110E48C*	15.4	13.0	7.8	19,600	210049465
CHX35-48C-*-+TDR	SL280UH100NV60C*	15.4	13.0	7.8	20,200	210049534
C35-49C+TDR+TXV	ML193UH110XE48C*	15.4	12.5	7.8	19,800	210049483
CX35-49C+TDR	SL280UH080NV60C*	15.4	13.0	7.8	19,900	210049591
CX35-49C+TDR	EL280UH110E48C*	15.4	13.0	7.8	19,600	210049566
CX35-49C+TDR	ML193UH110XE48C*	15.4	12.5	7.8	19,800	210066273
CX35-49C+TDR	EL280UH110E60C*	15.4	13.0	7.8	19,900	210049568
CX35-49C+TDR	ML180UH090E60C*	15.4	12.5	7.8	19,800	210049575
CX35-49C+TDR	EL280UH110XE60C*	15.4	13.0	7.8	19,900	210049570
C35-49C+TDR+TXV	ML180UH110E60C*	15.4	12.5	7.8	19,800	210049478
C35-49C+TDR+TXV	EL280UH110E60C*	15.4	13.0	7.8	19,900	210049467
CHX35-48C-*-+TDR	ML180UH110V60C*	15.4	13.0	7.8	10,400	210049529
C35-49C+TDR+TXV	SL280UH080NV60C*	15.4	13.0	7.8	19,900	210049496
C35-49C+TDR+TXV	ML180UH090E60C*	15.4	12.5	7.8	19,800	210049476
CX35-49C+TDR	ML180UH110E60C*	15.4	12.5	7.8	19,800	210049577
C35-49C+TDR+TXV	EL280UH110XE60C*	15.4	13.0	7.8	19,900	210049470
C35-48C+TDR+TXV	ML296UH110XV60C*	15.4	13.0	7.8	20,000	210857166
C35-48C+TDR+TXV	ML196UH090XE60C*	15.4	13.0	7.8	19,900	210857164
C35-48C+TDR+TXV	ML193UH110XE48C*	15.4	13.0	7.8	19,600	210857162

Yearly running cost in 10 large cities$1,240-$3,040

Phoenix, AZ$1,495/yr
Miami, FL$1,246/yr
Houston, TX$1,339/yr
Atlanta, GA$1,300/yr
Los Angeles, CA$1,253/yr
New York, NY$3,040/yr
Chicago, IL$2,455/yr
Denver, CO$2,031/yr
Seattle, WA$1,240/yr
Minneapolis, MN$2,509/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 Lennox ML17XP1-042-230A?: The Lennox ML17XP1-042-230A is rated at up to 15.6 SEER2 and 13.0 EER2 for cooling and up to 8.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 206 certified matchups SEER2 ranges from 15.2-15.6.
Is the Lennox ML17XP1-042-230A good for cold climates?: It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 3.5-ton model.
How much does the Lennox ML17XP1-042-230A cost to run per year?: At its rated efficiency it costs about $1,240-$3,040 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,495 in Phoenix and $2,509 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 Lennox ML17XP1-042-230A?: ENERGY STAR lists 206 certified combinations for this outdoor unit. The highest-rated ones use CBA27UHE-042-230*+TDR, CBA38MV-042-230*+TDR, CRX35-48C-**-*+TDR.
What refrigerant does the Lennox ML17XP1-042-230A 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 $1,463/yrYou save $636/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 ML17XP1-042-230A

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: $1,463
Current system, per year: $2,099
You save per year: $636
Payback: 24.4 years
Net after 10 years: -$9,137

Cooling $936Heating $526Electricity used: 9,142 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 3.5 ton models

MRCOOL MHP17L42P-**A15.6 SEER2 · 8.3 HSPF2
GE NS17H42SA4-**A15.6 SEER2 · 8.3 HSPF2
Hisense AUWR-48U3SP · cold climate15.6 SEER2 · 8.6 HSPF2
Ducane 4HP17L42P-**A15.6 SEER2 · 8.3 HSPF2
AIREASE A7HP14F42P-**A15.5 SEER2 · 8.2 HSPF2
Comfort-Aire HRG1542S1R-**A15.6 SEER2 · 8.3 HSPF2
Concord 7HP14F42P-**A15.5 SEER2 · 8.2 HSPF2
Blueridge BHP17L42P-**A15.6 SEER2 · 8.3 HSPF2

See all 138 3.5 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of October 27, 2025. How we use the data.