What is the SEER2 rating of the Breeze33 HSZ18H424ZMO?

The Breeze33 HSZ18H424ZMO is rated at up to 22.0 SEER2 and 13.0 EER2 for cooling and up to 11.2 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 12 certified matchups SEER2 ranges from 17.6-22.0.

Is the Breeze33 HSZ18H424ZMO good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 17,700 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 Breeze33 HSZ18H424ZMO cost to run per year?

At its rated efficiency it costs about $364-$1,007 a year in electricity in large U.S. cities, depending on climate and local rates - for example $453 in Phoenix and $845 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 Breeze33 HSZ18H424ZMO?

ENERGY STAR lists 12 certified combinations for this outdoor unit. The highest-rated ones use SEA BREEZE+ WM18H424ZMI, FC18H424ZMI, SEA BREEZE+ FC18H424ZMI.

What refrigerant does the Breeze33 HSZ18H424ZMO 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.

18,000 BTU mini-split heat pump · HS series

Breeze33 HSZ18H424ZMO

Average cooling efficiency and very good heating efficiency for a 18,000 BTU mini-split heat pump, and certified for cold climates.

Ranks #197 of 465 18,000 BTU mini-splits for cooling efficiency, and costs about $418 a year to run in a mixed climate like Atlanta.

SEER2: 22.0 Cooling efficiency over a season
Average · beats 48%
HSPF2: 11.2 Heating efficiency over a season
Very good · beats 79%
EER2: 13.0 Cooling efficiency on a 95°F day
Average · beats 62%
Heat at 5°F: 17,700 BTU/h96% 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 17,700 BTU/h at 5°F.
It will heat most of the year - its HSPF2 beats 79% of mini-splits.
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…

You want the newest refrigerant - it uses R-410A, which is being phased down.

Calculate my running cost

Details

Specifications18,000 BTU, R-410A

General
Brand	Breeze33
Also sold as	Sea Breeze
Outdoor unit model	HSZ18H424ZMO
Series	HS series
Type	Mini-split heat pump
Nominal size	18,000 BTU
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-410A
Connected (smart) capable	No
On the market since	January 1, 2022
Last certified	June 25, 2026
Cooling
SEER2Seasonal efficiency, higher is better	22.0 (range 17.6-22.0)
EER2Efficiency at 95°F outdoors	11.0-13.0
Cooling capacity	16,000-18,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.9-11.2
Capacity at 47°F	17,000-20,000 BTU/h
Capacity at 17°F	11,100-15,600 BTU/h
Capacity at 5°F	16,000-17,700 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.75-2.00
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 WM18H424ZMI 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.
WM18H424ZMI SEA BREEZE+ · cold climate	22.0	13.0	10.6	17,200	208816890
FC18H424ZMI · cold climate	20.5	12.5	9.8	16,800	211277592
FC18H424ZMI SEA BREEZE+ · cold climate	20.5	12.5	9.8	16,800	212595653
C18H424ZMI · cold climate	20.2	11.0	8.9	16,700	211277591
C18H424ZMI SEA BREEZE+ · cold climate	20.2	11.0	8.9	16,700	212595652
CA18H424ZMI · cold climate	20.0	12.5	9.5	16,000	211277588
CA18H424ZMI SEA BREEZE+ · cold climate	20.0	12.5	9.5	16,000	212595649
SCA18H424ZMI · cold climate	19.8	12.5	11.2	16,700	211277589
SCA18H424ZMI SEA BREEZE+ · cold climate	19.8	12.5	11.2	16,700	212595650
D18H424ZMI · cold climate	18.0	11.7	9.5	17,700	211277590
D18H424ZMI SEA BREEZE+ · cold climate	18.0	11.7	9.5	17,700	212595651
AH18H424ZMI · cold climate	17.6	11.7	9.6	17,000	211277597

Yearly running cost in 10 large cities$364-$1,007

Phoenix, AZ$453/yr
Miami, FL$364/yr
Houston, TX$406/yr
Atlanta, GA$418/yr
Los Angeles, CA$408/yr
New York, NY$1,007/yr
Chicago, IL$819/yr
Denver, CO$682/yr
Seattle, WA$420/yr
Minneapolis, MN$845/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 Breeze33 HSZ18H424ZMO?: The Breeze33 HSZ18H424ZMO is rated at up to 22.0 SEER2 and 13.0 EER2 for cooling and up to 11.2 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 12 certified matchups SEER2 ranges from 17.6-22.0.
Is the Breeze33 HSZ18H424ZMO good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 17,700 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 Breeze33 HSZ18H424ZMO cost to run per year?: At its rated efficiency it costs about $364-$1,007 a year in electricity in large U.S. cities, depending on climate and local rates - for example $453 in Phoenix and $845 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 Breeze33 HSZ18H424ZMO?: ENERGY STAR lists 12 certified combinations for this outdoor unit. The highest-rated ones use SEA BREEZE+ WM18H424ZMI, FC18H424ZMI, SEA BREEZE+ FC18H424ZMI.
What refrigerant does the Breeze33 HSZ18H424ZMO 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 $452/yrYou save $441/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 Breeze33 HSZ18H424ZMO

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: $452
Current system, per year: $893
You save per year: $441
Payback: 14.7 years
Net after 10 years: -$2,091

Cooling $272Heating $180Electricity used: 2,825 kWhSaved vs. a minimum-efficiency heat pump: $235

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 18,000 BTU models

NOVAIR LEA18SZ35SK-O · cold climate22.0 SEER2 · 11.3 HSPF2
DuraSTAR DRA1H18S1A · cold climate22.0 SEER2 · 11.2 HSPF2
MDV MOX430-17HFN1-MT0W · cold climate22.0 SEER2 · 11.3 HSPF2
Mitsubishi Electric SUZ-KA18NA22.0 SEER2 · 11.2 HSPF2
Heil DLCSRBH18AAK · cold climate22.0 SEER2 · 11.3 HSPF2
Mitsutomo HO-SZ18-AB-Q · cold climate22.0 SEER2 · 11.2 HSPF2
Cooper&Hunter CH-HPR18-230VO · cold climate22.0 SEER2 · 11.3 HSPF2
Fujitsu AOUH18KWAH2 · cold climate22.0 SEER2 · 11.0 HSPF2

See all 465 18,000 BTU mini-splits, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 25, 2026. How we use the data.