What is the best 42,000 BTU mini-split?

On certified efficiency, the MDV M6OE30-48HFN10-M1 leads at 24.0 SEER2 and 10.6 HSPF2. For cold climates the Fujitsu AOUH42KUAS1 has the best efficiency at 5°F (COP 2.36). For very hot summers the LG KUMXA421A has the highest EER2 (13.8). The right pick depends on your climate, so compare the lists above.

How much does a 42,000 BTU mini-split cost to run?

A typical 42,000 BTU mini-split (21.3 SEER2, 10.6 HSPF2) uses about $1,043 of electricity a year in a mixed climate like Atlanta, roughly $87 a month on average. Across U.S. climates it ranges from $1,027 to $2,089 a year. The most efficient model in this class saves about $43 a year in Atlanta.

Which 42,000 BTU mini-split works best in cold weather?

Look for ENERGY STAR cold-climate certification (56 of 61 qualify). The Fujitsu AOUH42KUAS1 has the highest COP at 5°F in this class (2.36) and delivers 37,000 BTU/h at 5°F. Cold-climate units are often marketed as hyper-heat or low-ambient models.

Best 42,000 BTU mini-splits

61 ENERGY STAR certified 42,000 BTU mini-splits from 31 brands, ranked on their official ratings. Here are the winners for each kind of home, then the full list.

Best overall

MDV M6OE30-48HFN10-M1

42,000 BTU mini-split · M6O Series · cold-climate certified

SEER2: 24.0
HSPF2: 10.6
Heat at 5°F: 38,000

Highest seasonal cooling efficiency of all 61 42,000 BTU mini-splits, with 10.6 HSPF2 for heating.

Full specs and running cost

Best for cold winters

Fujitsu AOUH42KUAS1

42,000 BTU mini-split · AIRSTAGE H-series · cold-climate certified

SEER2: 19.0
HSPF2: 10.4
COP at 5°F: 2.36

Cold-climate certified, with one of the best efficiencies at 5°F in this size (COP 2.36).

Full specs and running cost

Best for hot summers

LG KUMXA421A

42,000 BTU mini-split · cold-climate certified

SEER2: 21.5
HSPF2: 11.0
EER2: 13.8

EER2 of 13.8: among the most efficient on a 95°F afternoon.

Full specs and running cost

Area one unit coversabout 1,400-2,650 sq ft
Typical running cost$1,043/yr in Atlanta
Average efficiency20.9 SEER2
Cold-climate certified56 of 61

Compare all 61 42,000 BTU mini-splits

61 models, ranked by SEER2 (cooling efficiency), then HSPF2.

#							Cold
1	MDV M6OE30-48HFN10-M1M6O Series	42,000 BTU	24.0	12.5	10.6	38,000	Yes	6
2	MDV M6OE30-48HFN10-M1DM6O Series	42,000 BTU	24.0	12.5	10.6	38,000	Yes	7
3	AUX AM5-H42/2DR3BC-Series	42,000 BTU	24.0	12.5	10.5	34,000	Yes	1
4	AUX ASUM42HPMULOC-Series	42,000 BTU	24.0	12.5	10.5	35,000	Yes	3
5	DELLA 048-TCQ-MODU-1D5TC	42,000 BTU	24.0	11.2	10.0	31,000	Yes	2
6	TCL H42FMH22XQCfree matcht 24S R32	42,000 BTU	24.0	11.2	10.0	31,000	Yes	1
7	TCL TMH42HDI2NAO0U25free matcht 24S R32	42,000 BTU	24.0	11.2	10.0	31,000	Yes	4
8	York YRAMX42N5HBAMH MULTI-SPLIT	42,000 BTU	23.0	12.5	10.5	40,000	Yes	3
9	York YRAMG42N5HAAMJ Multi-Split	42,000 BTU	23.0	12.5	9.2	29,400	No	1
10	TOSHIBA CARRIER RAV-BP421AT2P-ULRAV-BP421AT2P-UL	42,000 BTU	22.6	12.0	11.2	33,400	Yes	1
11	Hitachi PAS-48BUFASDQ1-LACairCore700	42,000 BTU	22.5	13.0	10.0	34,200	Yes	3
12	MDV M5OG-42HFN1-M-[X]M5O series	42,000 BTU	22.3	11.7	10.5	44,000	Yes	2
13	Fujitsu AOUH42KUAH1AIRSTAGE H-series	42,000 BTU	22.0	13.0	10.6	48,000	Yes	2
14	Ameristar M5THM2342A15NA23U Multi	42,000 BTU	22.0	11.2	10.0	30,000	Yes	2
15	Fujitsu AOUH45KWAS5AIRSTAGE H-series	42,000 BTU	22.0	12.0	10.0	36,000	Yes	3
16	Fujitsu AOUH45KWBS5AIRSTAGE H-series	42,000 BTU	22.0	12.0	10.0	36,000	Yes	3
17	TCL H42FMH20XPCMULIT ZONE	42,000 BTU	22.0	11.2	10.0	33,000	Yes	3
18	TURBRO GREENLAND-M42K/OT-Pro	42,000 BTU	22.0	11.2	10.0	30,000	Yes	1
19	ZERO Z5SOV-42HDTB-USZ-MAX	42,000 BTU	22.0	11.2	10.0	33,000	Yes	2
20	Friedrich FPHMR42A3DFloating Air Pro X Multi-Zone	42,000 BTU	22.0	12.0	9.5	36,000	Yes	10
21	Guardian UMC48CN23STG1UMULTI	42,000 BTU	22.0	12.0	9.5	36,000	Yes	9
22	Hisense AMW5-42U3TQAHi MULTI Xtreme	42,000 BTU	22.0	12.0	9.5	36,000	Yes	3
23	OLMO OS-RMS42-230VOSIERRA	42,000 BTU	22.0	12.0	9.5	36,000	Yes	1
24	InfinityLiving EZ-48Z-M5BEZ Series	42,000 BTU	21.8	12.0	10.5	37,000	Yes	12
25	MRCOOL DIY-MULTI6-48HP230D-ODIY Series	42,000 BTU	21.8	12.0	10.5	37,000	Yes	3
26	Mitsubishi Electric MXZ-SM42NAMHZ2Smart Multi	42,000 BTU	21.5	13.4	11.1	44,000	Yes	5
27	Mitsubishi Electric MXZ-SM42NLHZSmart Multi	42,000 BTU	21.5	13.4	11.1	48,000	Yes	3
28	LG KUMXA421AKUMXA421A	42,000 BTU	21.5	13.8	11.0	44,000	Yes	3
29	LG KUSXA421AKUSXA421A	42,000 BTU	21.5	13.5	10.8	43,500	Yes	2
30	Trane / Mitsubishi Electric PUZ-A42NKA7P-Series	42,000 BTU	21.5	11.6	9.4	20,000	No	2
31	AproDr AM6OG-48HFN1AM Series	42,000 BTU	21.3	11.7	10.6	38,000	Yes	6
32	Panasonic CU - 6YM48CBUCCU Series	42,000 BTU	21.3	11.7	10.6	38,000	Yes	3
33	LG KUSXB421AKUSXB421A	42,000 BTU	21.0	13.2	10.8	40,000	Yes	6
34	Mitsubishi Electric PUZ-AK42NLP series	42,000 BTU	21.0	12.0	10.1	25,400	No	3
35	Mitsubishi Electric PUZ-AK42NL2P series	42,000 BTU	21.0	12.0	10.1	25,400	No	3
36	AireForce DXH42FMK3IHMultizone Outdoors	42,000 BTU	21.0	13.0	10.0	37,800	Yes	12
37	ECO AC EMH-5O42KBBMulti-Zone Outdoor	42,000 BTU	21.0	13.0	10.0	37,800	Yes	1
38	TOSOT TM42D6MOR32 FreeMatch	42,000 BTU	21.0	13.0	10.0	37,800	Yes	3
39	TOSOT TM42H32MOM-Series	42,000 BTU	21.0	13.0	10.0	37,800	Yes	3
40	Lennox MMPD048S6M-1PMMPD Multi-Zone	42,000 BTU	21.0	11.7	9.0	31,400	No	3
41	GE Appliances 5G42ED2BEEndure Multi	42,000 BTU	20.5	10.5	9.5	35,000	Yes	3
42	Hitachi PAS-48BUFASDQ1airCore700	42,000 BTU	20.0	13.0	10.8	39,500	Yes	5
43	York YPAS48BUFASDQ1airCore700	42,000 BTU	20.0	13.0	10.8	39,500	Yes	4
44	Friedrich FPHFR48A3DFloating Air Pro X	42,000 BTU	20.0	12.0	10.0	48,000	Yes	9
45	Daikin 5MXT40AVJUAURORA Multi	42,000 BTU	20.0	11.7	9.5	38,000	Yes	3
46	Guardian UPC48CN23STG1UPAC	42,000 BTU	20.0	12.0	9.5	48,000	Yes	9
47	Hisense AUW-48U3TH1(JCH)Hi UNI	42,000 BTU	20.0	12.0	9.5	44,000	Yes	3
48	Mitsubishi Electric PUZ-AK42NLHZP series	42,000 BTU	20.0	11.8	9.2	48,000	Yes	5
49	Friedrich FPHMR42A3APro	42,000 BTU	20.0	10.5	9.0	36,000	Yes	3
50	OLMO OS-MSR42-230VOSIERRA	42,000 BTU	20.0	10.5	9.0	36,000	Yes	1
51	Westinghouse WHP42M5A21SHi MULTI Xtreme	42,000 BTU	20.0	10.5	9.0	36,000	Yes	2
52	DELLA 048-TLP-MODU-1D5MODU	42,000 BTU	19.5	11.1	9.0	33,000	Yes	1
53	Fujitsu AOUH42KUAS1AIRSTAGE H-series	42,000 BTU	19.0	10.8	10.4	37,000	Yes	2
54	LG KUSUB421AKUSUB421A	42,000 BTU	18.5	11.0	9.5	36,800	Yes	1
55	GE Appliances ASH4248UCDDEndure PRO	42,000 BTU	18.0	8.7	8.8	36,800	Yes	3
56	TOSOT TGWHD-42NDMulti R32 AO	42,000 BTU	17.0	11.0	8.5	29,400	Yes	1
57	Mitsubishi Electric PUZ-HA42NKA2P-Series	42,000 BTU	16.3	10.7	9.3	48,000	Yes	3
58	Trane / Mitsubishi Electric PUZ-HA42NKA1P-Series	42,000 BTU	16.3	10.7	9.3	48,000	Yes	7
59	ACD MUD42KCH23S-OUltra heat free match	42,000 BTU	16.0	9.0	8.6	31,200	Yes	1
60	Trane 4TXM2336A15NU23 MZ Series	42,000 BTU	16.0	9.0	8.6	31,200	Yes	2
61	Mitsubishi Electric PUZ-HA42NKAP-Series	42,000 BTU	15.4	10.0	8.9	48,000	Yes	1

More about 42,000 BTU mini-splits

Top 5 for cold climatesranked by COP at 5°F

Cold-climate certified models with the highest efficiency at 5°F. Often sold as hyper-heat or low-ambient models.

#	Model	SEER2	EER2	HSPF2	COP at 5°F
1	Fujitsu AOUH42KUAS1	19.0	10.8	10.4	2.36
2	LG KUSXA421A	21.5	13.5	10.8	2.20
3	Hitachi PAS-48BUFASDQ1-LAC	22.5	13.0	10.0	2.20
4	Fujitsu AOUH45KWAS5	22.0	12.0	10.0	2.14
5	Fujitsu AOUH45KWBS5	22.0	12.0	10.0	2.14

Top 5 for hot climatesranked by EER2

Highest efficiency on a 95°F afternoon, which drives summer bills in places like Phoenix, Houston and Florida.

#	Model	SEER2	EER2	HSPF2	COP at 5°F
1	LG KUMXA421A	21.5	13.8	11.0	2.00
2	LG KUSXA421A	21.5	13.5	10.8	2.20
3	Mitsubishi Electric MXZ-SM42NAMHZ2also sold as 1 other model number	21.5	13.4	11.1	2.00
4	Mitsubishi Electric MXZ-SM42NLHZalso sold as 2 other model numbers	21.5	13.4	11.1	2.00
5	LG KUSXB421A	21.0	13.2	10.8	1.96

Top 5 for heatingranked by HSPF2

Highest seasonal heating efficiency, for homes where the heat pump replaces a furnace.

#	Model	SEER2	EER2	HSPF2	COP at 5°F
1	TOSHIBA CARRIER RAV-BP421AT2P-UL	22.6	12.0	11.2	2.10
2	Mitsubishi Electric MXZ-SM42NAMHZ2also sold as 1 other model number	21.5	13.4	11.1	2.00
3	Mitsubishi Electric MXZ-SM42NLHZalso sold as 2 other model numbers	21.5	13.4	11.1	2.00
4	LG KUMXA421A	21.5	13.8	11.0	2.00
5	LG KUSXA421A	21.5	13.5	10.8	2.20

How many square feet does a 42,000 BTU mini-split cover?1,400-2,650 sq ft

Hot and dry climate (Phoenix)up to 2,650 sq ft
Hot and humid climate (Houston)up to 2,650 sq ft
Mixed climate (Atlanta)up to 2,250 sq ft
Cold climate (Chicago)up to 1,550 sq ft
Very cold climate (Minneapolis)up to 1,400 sq ft

Average insulation, 8 ft ceilings. Sunny rooms, kitchens and older houses need more capacity. Size calculator

What a 42,000 BTU mini-split costs to run$87/month typical

Hot and dry (Phoenix)$1,145/yr · best $1,051
Hot and humid (Houston)$1,027/yr · best $943
Mixed (Atlanta)$1,043/yr · best $1,000
Cold (Chicago)$2,029/yr · best $1,995
Very cold (Minneapolis)$2,089/yr · best $2,067

Typical = median model of this size (21.3 SEER2, 10.6 HSPF2); best = most efficient. Local electricity prices from the U.S. EIA. Calculate for your home

Questions4

What is the best 42,000 BTU mini-split?: On certified efficiency, the MDV M6OE30-48HFN10-M1 leads at 24.0 SEER2 and 10.6 HSPF2. For cold climates the Fujitsu AOUH42KUAS1 has the best efficiency at 5°F (COP 2.36). For very hot summers the LG KUMXA421A has the highest EER2 (13.8). The right pick depends on your climate, so compare the lists above.
How many square feet does a 42,000 BTU mini-split cover?: About 1,400 to 2,650 sq ft with average insulation: 2,650 sq ft in a hot and dry climate like Phoenix, 2,650 sq ft in a hot and humid climate like Houston, 2,250 sq ft in a mixed climate like Atlanta, 1,550 sq ft in a cold climate like Chicago, 1,400 sq ft in a very cold climate like Minneapolis. Cold climates cover less because the heating load is larger.
How much does a 42,000 BTU mini-split cost to run?: A typical 42,000 BTU mini-split (21.3 SEER2, 10.6 HSPF2) uses about $1,043 of electricity a year in a mixed climate like Atlanta, roughly $87 a month on average. Across U.S. climates it ranges from $1,027 to $2,089 a year. The most efficient model in this class saves about $43 a year in Atlanta.
Which 42,000 BTU mini-split works best in cold weather?: Look for ENERGY STAR cold-climate certification (56 of 61 qualify). The Fujitsu AOUH42KUAS1 has the highest COP at 5°F in this class (2.36) and delivers 37,000 BTU/h at 5°F. Cold-climate units are often marketed as hyper-heat or low-ambient models.

Other sizes

ENERGY STAR data, updated October 12, 2026

Best 42,000 BTU mini-splits

Top picks

MDV M6OE30-48HFN10-M1

Fujitsu AOUH42KUAS1

LG KUMXA421A

Compare all 61 42,000 BTU mini-splits

More about 42,000 BTU mini-splits

Other sizes