What is the SEER2 rating of the InfinityLiving EZ-48Z-M5B?

The InfinityLiving EZ-48Z-M5B is rated at up to 21.8 SEER2 and 12.0 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 12 certified matchups SEER2 ranges from 20.0-21.8.

Is the InfinityLiving EZ-48Z-M5B good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 37,000 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 InfinityLiving EZ-48Z-M5B cost to run per year?

At its rated efficiency it costs about $932-$2,785 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,189 in Phoenix and $2,358 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

42,000 BTU mini-split heat pump · EZ Series

InfinityLiving EZ-48Z-M5B

Average cooling and heating efficiency for a 42,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #24 of 61 42,000 BTU mini-splits for cooling efficiency, and costs about $1,136 a year to run in a mixed climate like Atlanta.

SEER2: 21.8 Cooling efficiency over a season
Average · beats 44%
HSPF2: 10.5 Heating efficiency over a season
Average · beats 61%
EER2: 12.0 Cooling efficiency on a 95°F day
Below average · beats 25%
Heat at 5°F: 37,000 BTU/h77% 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 37,000 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.
You want a choice of indoor units - 12 certified pairings.

Think twice if…

Nothing stands out - its ratings have no weak spot for its class.

Calculate my running cost

Details

Specifications42,000 BTU, R-454B

General
Brand	InfinityLiving
Also sold as	DIYCOOL, PolarWave, 1HVAC
Outdoor unit model	EZ-48Z-M5B
Series	EZ Series
Type	Mini-split heat pump
Nominal size	42,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	February 10, 2025
Last certified	March 4, 2025
Cooling
SEER2Seasonal efficiency, higher is better	21.8 (range 20.0-21.8)
EER2Efficiency at 95°F outdoors	12.0
Cooling capacity	43,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	10.0-10.5
Capacity at 47°F	47,000-48,000 BTU/h
Capacity at 17°F	35,200-37,800 BTU/h
Capacity at 5°F	37,000 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 colder77% kept at 5°F

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

Certified matchups12 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.
- · cold climate	21.8	12.0	10.0	37,000	216980916
- DIYCOOL · cold climate	21.8	12.0	10.0	37,000	216980926
- PolarWave · cold climate	21.8	12.0	10.0	37,000	216980936
- 1HVAC · cold climate	21.8	12.0	10.0	37,000	216980946
- · cold climate	20.9	12.0	10.3	37,000	216980918
- DIYCOOL · cold climate	20.9	12.0	10.3	37,000	216980928
- PolarWave · cold climate	20.9	12.0	10.3	37,000	216980938
- 1HVAC · cold climate	20.9	12.0	10.3	37,000	216980948
- · cold climate	20.0	12.0	10.5	37,000	216980917
- DIYCOOL · cold climate	20.0	12.0	10.5	37,000	216980927
- PolarWave · cold climate	20.0	12.0	10.5	37,000	216980937
- 1HVAC · cold climate	20.0	12.0	10.5	37,000	216980947

Yearly running cost in 10 large cities$932-$2,785

Phoenix, AZ$1,189/yr
Miami, FL$932/yr
Houston, TX$1,067/yr
Atlanta, GA$1,136/yr
Los Angeles, CA$1,118/yr
New York, NY$2,785/yr
Chicago, IL$2,274/yr
Denver, CO$1,902/yr
Seattle, WA$1,177/yr
Minneapolis, MN$2,358/yr

At each state's average electricity price and the city's typical heating and cooling hours.

Questions4

What is the SEER2 rating of the InfinityLiving EZ-48Z-M5B?: The InfinityLiving EZ-48Z-M5B is rated at up to 21.8 SEER2 and 12.0 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 12 certified matchups SEER2 ranges from 20.0-21.8.
Is the InfinityLiving EZ-48Z-M5B good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 37,000 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 InfinityLiving EZ-48Z-M5B cost to run per year?: At its rated efficiency it costs about $932-$2,785 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,189 in Phoenix and $2,358 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
What refrigerant does the InfinityLiving EZ-48Z-M5B 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 $1,201/yrYou save $1,090/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 InfinityLiving EZ-48Z-M5B

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: $1,201
Current system, per year: $2,291
You save per year: $1,090
Payback: 14.7 years
Net after 10 years: -$5,102

Cooling $694Heating $507Electricity used: 7,506 kWhSaved vs. a minimum-efficiency heat pump: $567

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 42,000 BTU models

OLMO OS-RMS42-230VO · cold climate22.0 SEER2 · 9.5 HSPF2
MRCOOL DIY-MULTI6-48HP230D-O · cold climate21.8 SEER2 · 10.5 HSPF2
Hisense AMW5-42U3TQA · cold climate22.0 SEER2 · 9.5 HSPF2
Mitsubishi Electric MXZ-SM42NAMHZ2 · cold climate21.5 SEER2 · 11.1 HSPF2
Guardian UMC48CN23STG1 · cold climate22.0 SEER2 · 9.5 HSPF2
Mitsubishi Electric MXZ-SM42NLHZ · cold climate21.5 SEER2 · 11.1 HSPF2
Friedrich FPHMR42A3D · cold climate22.0 SEER2 · 9.5 HSPF2
LG KUMXA421A · cold climate21.5 SEER2 · 11.0 HSPF2

See all 61 42,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 4, 2025. How we use the data.