What is the SEER2 rating of the Thermal Zone TZID18H520ZCS?

The Thermal Zone TZID18H520ZCS is rated at up to 18.8 SEER2 and 11.0 EER2 for cooling and up to 9.1 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 7 certified matchups SEER2 ranges from 16.1-18.8.

Is the Thermal Zone TZID18H520ZCS 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 1.5-ton model.

How much does the Thermal Zone TZID18H520ZCS cost to run per year?

At its rated efficiency it costs about $450-$1,241 a year in electricity in large U.S. cities, depending on climate and local rates - for example $560 in Phoenix and $1,040 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 Thermal Zone TZID18H520ZCS?

ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use TZID18H520ZAM, TZID24H520ZACB, TZID24H520ZACA.

1.5-ton central heat pump · TZID Series

Thermal Zone TZID18H520ZCS

Very good cooling efficiency and average heating efficiency for a 1.5-ton central heat pump, but not rated for cold climates.

Ranks #53 of 170 1.5 ton central heat pumps for cooling efficiency, and costs about $515 a year to run in a mixed climate like Atlanta.

SEER2: 18.8 Cooling efficiency over a season
Very good · beats 81%
HSPF2: 9.1 Heating efficiency over a season
Average · beats 60%
EER2: 11.0 Cooling efficiency on a 95°F day
Below average · beats 23%
Heat at 5°F: 11,200 BTU/h62% of its 47°F output
Below average · beats 39%

A good fit if…

You want low cooling bills - its SEER2 beats 81% of central heat pumps.
You want steady temperatures and quiet running - the compressor varies its speed.

Think twice if…

You often see nights below 0°F - it is not cold-climate certified.

Calculate my running cost

Details

Specifications1.5 ton, R-454B

General
Brand	Thermal Zone
Outdoor unit model	TZID18H520ZCS
Series	TZID Series
Type	Central heat pump
Nominal size	1.5 ton
CompressorVariable-speed units run longer at low power	Continuously variable
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	December 20, 2025
Last certified	September 22, 2026
Cooling
SEER2Seasonal efficiency, higher is better	18.8 (range 16.1-18.8)
EER2Efficiency at 95°F outdoors	11.0-11.2
Cooling capacity	18,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.2-9.1
Capacity at 47°F	18,000-19,000 BTU/h
Capacity at 17°F	11,000-12,600 BTU/h
Capacity at 5°F	10,000-11,200 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.80-2.00
ENERGY STAR cold climate	No

Heating output as it gets colder62% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with TZID18H520ZAM at the standard test temperatures, in BTU/h:

Certified matchups7 indoor units

The same outdoor unit scores differently with each indoor unit and furnace. 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.
TZID18H520ZAM	-	18.8	11.0	9.1	11,200	218043392
TZID24H520ZACB	ML193DF070XE36B*	17.7	11.0	8.3	10,000	218079950
TZID24H520ZACA	RL18060A12MPS1	17.0	11.0	8.2	10,000	218782192
TZID24H520ZACB	MGV96U060B3C	16.4	11.0	8.4	10,000	218079687
TZID24H520ZACB	RL18080B12MPS1	16.2	11.2	8.3	10,000	218079839
TZID24H520ZACB	MGV96U080B3C	16.1	11.0	8.4	10,000	218079688
TZID24H520ZACA	RL18040A12MPS1	16.1	11.0	8.2	10,000	218782191

Yearly running cost in 10 large cities$450-$1,241

Phoenix, AZ$560/yr
Miami, FL$450/yr
Houston, TX$502/yr
Atlanta, GA$515/yr
Los Angeles, CA$503/yr
New York, NY$1,241/yr
Chicago, IL$1,009/yr
Denver, CO$840/yr
Seattle, WA$517/yr
Minneapolis, MN$1,040/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 Thermal Zone TZID18H520ZCS?: The Thermal Zone TZID18H520ZCS is rated at up to 18.8 SEER2 and 11.0 EER2 for cooling and up to 9.1 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 7 certified matchups SEER2 ranges from 16.1-18.8.
Is the Thermal Zone TZID18H520ZCS 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 1.5-ton model.
How much does the Thermal Zone TZID18H520ZCS cost to run per year?: At its rated efficiency it costs about $450-$1,241 a year in electricity in large U.S. cities, depending on climate and local rates - for example $560 in Phoenix and $1,040 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 Thermal Zone TZID18H520ZCS?: ENERGY STAR lists 7 certified combinations for this outdoor unit. The highest-rated ones use TZID18H520ZAM, TZID24H520ZACB, TZID24H520ZACA.
What refrigerant does the Thermal Zone TZID18H520ZCS 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 $559/yrYou save $370/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 Thermal Zone TZID18H520ZCS

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: $559
Current system, per year: $928
You save per year: $370
Payback: 18.9 years
Net after 10 years: -$3,304

Cooling $337Heating $222Electricity used: 3,491 kWhSaved vs. a minimum-efficiency heat pump: $153

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.

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Elios ESHEA18R2AN118.5 SEER2 · 9.4 HSPF2
DIRECT AIR DIRM4-18CS19-OU18.8 SEER2 · 9.1 HSPF2
UTL UCHA-18HFDCSN4 · cold climate18.5 SEER2 · 9.2 HSPF2
AproDr AHU19-18HN1-C18.8 SEER2 · 9.1 HSPF2
GREE GUD12W2/NHE-D(U) · cold climate18.5 SEER2 · 9.0 HSPF2

See all 170 1.5 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of September 22, 2026. How we use the data.