What is the SEER2 rating of the ZERO ZMSB-33HV-USHHCR2-O?

The ZERO ZMSB-33HV-USHHCR2-O is rated at up to 20.0 SEER2 and 11.7 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.

Is the ZERO ZMSB-33HV-USHHCR2-O good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 34,600 BTU/h at 5°F with a COP of 1.91, so it is still 1.9 times as efficient as electric resistance heat at that temperature.

How much does the ZERO ZMSB-33HV-USHHCR2-O cost to run per year?

At its rated efficiency it costs about $776-$2,148 a year in electricity in large U.S. cities, depending on climate and local rates - for example $967 in Phoenix and $1,802 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the ZERO ZMSB-33HV-USHHCR2-O the same as the SLIMAIR SHC30AH2AG?

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 ZERO ZMSB-33HV-USHHCR2-O?

ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use ZMSB-33HV-USHHCR2-I, ZWAVAG-33HDMB-US.

30,000 BTU mini-split heat pump · ZMSB Series

ZERO ZMSB-33HV-USHHCR2-O

Below average cooling efficiency and average heating efficiency for a 30,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #126 of 171 30,000 BTU mini-splits for cooling efficiency, and costs about $892 a year to run in a mixed climate like Atlanta.

SEER2: 20.0 Cooling efficiency over a season
Below average · beats 18%
HSPF2: 10.5 Heating efficiency over a season
Average · beats 61%
EER2: 11.7 Cooling efficiency on a 95°F day
Below average · beats 16%
Heat at 5°F: 34,600 BTU/h96% of its 47°F output
Below average · beats 31%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 34,600 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

Cooling cost matters most - its SEER2 is below average for mini-splits.

Calculate my running cost

Details

Specifications30,000 BTU, R-454B

General
Brand	ZERO
Also sold as	SLIMAIR
Outdoor unit model	ZMSB-33HV-USHHCR2-O
Series	ZMSB Series
Type	Mini-split heat pump
Nominal size	30,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	November 11, 2024
Last certified	May 6, 2026
Cooling
SEER2Seasonal efficiency, higher is better	20.0 (range 20.0)
EER2Efficiency at 95°F outdoors	11.7
Cooling capacity	33,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	10.5
Capacity at 47°F	36,000 BTU/h
Capacity at 17°F	31,000 BTU/h
Capacity at 5°F	34,600 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.91
ENERGY STAR cold climate	Yes

Heating output as it gets colder96% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with ZMSB-33HV-USHHCR2-I at the standard test temperatures, in BTU/h:

Certified matchups2 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.
ZMSB-33HV-USHHCR2-I · cold climate	20.0	11.7	10.5	34,600	216097677
ZWAVAG-33HDMB-US · cold climate	20.0	11.7	10.5	34,600	218043730

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the ZERO ZMSB-33HV-USHHCR2-O: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

SLIMAIR SHC30AH2AG

Yearly running cost in 10 large cities$776-$2,148

Phoenix, AZ$967/yr
Miami, FL$776/yr
Houston, TX$867/yr
Atlanta, GA$892/yr
Los Angeles, CA$871/yr
New York, NY$2,148/yr
Chicago, IL$1,747/yr
Denver, CO$1,455/yr
Seattle, WA$896/yr
Minneapolis, MN$1,802/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 ZERO ZMSB-33HV-USHHCR2-O?: The ZERO ZMSB-33HV-USHHCR2-O is rated at up to 20.0 SEER2 and 11.7 EER2 for cooling and up to 10.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
Is the ZERO ZMSB-33HV-USHHCR2-O good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 34,600 BTU/h at 5°F with a COP of 1.91, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
How much does the ZERO ZMSB-33HV-USHHCR2-O cost to run per year?: At its rated efficiency it costs about $776-$2,148 a year in electricity in large U.S. cities, depending on climate and local rates - for example $967 in Phoenix and $1,802 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the ZERO ZMSB-33HV-USHHCR2-O the same as the SLIMAIR SHC30AH2AG?: 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 ZERO ZMSB-33HV-USHHCR2-O?: ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use ZMSB-33HV-USHHCR2-I, ZWAVAG-33HDMB-US.
What refrigerant does the ZERO ZMSB-33HV-USHHCR2-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 $965/yrYou save $786/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 ZERO ZMSB-33HV-USHHCR2-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: $965
Current system, per year: $1,751
You save per year: $786
Payback: 15.9 years
Net after 10 years: -$4,642

Cooling $581Heating $384Electricity used: 6,030 kWhSaved vs. a minimum-efficiency heat pump: $385

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 30,000 BTU models

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MDV MOD30-33HFN10-M1X · cold climate20.0 SEER2 · 10.5 HSPF2
Lennox VPC030H5M-3P · cold climate20.0 SEER2 · 10.1 HSPF2
Mainline ML33HP230NEXH-O · cold climate20.0 SEER2 · 10.5 HSPF2
GE Appliances 1G3036ED2BE · cold climate20.0 SEER2 · 10.0 HSPF2
Cooper&Hunter CH-RHP33-230VO · cold climate20.0 SEER2 · 10.5 HSPF2
MDV MOD30-33HFN1-MSR0W · cold climate20.0 SEER2 · 10.0 HSPF2

See all 171 30,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of May 6, 2026. How we use the data.