What is the SEER2 rating of the Thermal Zone TZID48H520ZCS?

The Thermal Zone TZID48H520ZCS is rated at up to 16.7 SEER2 and 10.3 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 37 certified matchups SEER2 ranges from 15.2-16.7.

Is the Thermal Zone TZID48H520ZCS good for cold climates?

Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 42,000 BTU/h at 5°F with a COP of 1.85, so it is still 1.9 times as efficient as electric resistance heat at that temperature.

How much does the Thermal Zone TZID48H520ZCS cost to run per year?

At its rated efficiency it costs about $1,263-$3,145 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,525 in Phoenix and $2,603 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 TZID48H520ZCS?

ENERGY STAR lists 37 certified combinations for this outdoor unit. The highest-rated ones use TZID24H520ZACC, TZID48H520ZAM, TZID60H520ZACC.

3.5-ton central heat pump · TZID Series

Thermal Zone TZID48H520ZCS

Average cooling and heating efficiency for a 3.5-ton central heat pump, and certified for cold climates.

Ranks #49 of 138 3.5 ton central heat pumps for cooling efficiency, and costs about $1,338 a year to run in a mixed climate like Atlanta.

SEER2: 16.7 Cooling efficiency over a season
Average · beats 43%
HSPF2: 9.0 Heating efficiency over a season
Average · beats 54%
EER2: 10.3 Cooling efficiency on a 95°F day
Below average · beats 16%
Heat at 5°F: 42,000 BTU/h89% of its 47°F output
Below average · beats 12%

A good fit if…

Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 42,000 BTU/h at 5°F.
You want steady temperatures and quiet running - the compressor varies its speed.
You want a choice of indoor units - 37 certified pairings.

Think twice if…

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

Calculate my running cost

Details

Specifications3.5 ton, R-454B

General
Brand	Thermal Zone
Outdoor unit model	TZID48H520ZCS
Series	TZID Series
Type	Central heat pump
Nominal size	3.5 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	May 1, 2026
Cooling
SEER2Seasonal efficiency, higher is better	16.7 (range 15.2-16.7)
EER2Efficiency at 95°F outdoors	9.8-10.4
Cooling capacity	41,000-48,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	8.1-9.0
Capacity at 47°F	44,000-48,000 BTU/h
Capacity at 17°F	31,000-34,800 BTU/h
Capacity at 5°F	37,000-42,000 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.75-1.85
ENERGY STAR cold climate	Yes

Heating output as it gets colder89% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with TZID24H520ZACC at the standard test temperatures, in BTU/h:

Certified matchups37 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.
TZID24H520ZACC · cold climate	S9V2C100U5VS***	16.7	10.3	8.9	39,000	218079768
TZID24H520ZACC · cold climate	S9V2C100D5VS***	16.7	10.3	8.9	39,000	218079767
TZID24H520ZACC · cold climate	ML296UH110XV60C*	16.5	10.4	8.3	39,000	218079962
TZID24H520ZACC · cold climate	S9V2C080U5VS***	16.4	10.2	9.0	40,000	218079766
TZID24H520ZACC · cold climate	S9X2C080U5PSB**	16.3	10.1	8.6	39,000	218079806
TZID24H520ZACC · cold climate	S9X1C080U5PSB**	16.3	10.1	8.6	39,000	218079772
TZID24H520ZACC · cold climate	ML193UH110XE48C*	16.2	10.2	8.2	37,000	218080004
TZID24H520ZACC · cold climate	ML193UH110XE48B*	16.2	10.2	8.2	37,000	218079954
TZID48H520ZAM · cold climate	-	16.0	10.0	8.5	38,000	218043402
TZID24H520ZACC · cold climate	ML193UH090XE48C*	16.0	10.0	8.3	38,000	218080003
TZID24H520ZACC · cold climate	ML193UH090XE48B*	16.0	10.0	8.3	38,000	218079953
TZID24H520ZACC · cold climate	RL18100C20MPS1	16.0	10.4	8.2	38,000	218079850
TZID24H520ZACC · cold climate	MGV96U080C4C	15.9	9.9	8.9	41,000	218079693
TZID24H520ZACC · cold climate	ML296UH090XV48C*	15.9	10.3	8.2	39,000	218080009
TZID24H520ZACC · cold climate	ML193DF090XE48C*	15.9	10.1	8.2	37,000	218080001
TZID24H520ZACC · cold climate	ML296UH090XV48B*	15.9	10.3	8.2	39,000	218079961
TZID24H520ZACC · cold climate	ML193DF090XE48B*	15.9	10.1	8.2	37,000	218079952
TZID24H520ZACC · cold climate	ML196DF090XE48C*	15.9	10.0	8.1	37,000	218080006
TZID24H520ZACC · cold climate	ML196DF090XE48B*	15.9	10.0	8.1	37,000	218079956
TZID24H520ZACC · cold climate	ML296DF090XV60C*	15.8	10.2	8.2	39,000	218079960
TZID24H520ZACC · cold climate	ML196UH090XE48C*	15.8	10.0	8.1	37,000	218080008
TZID24H520ZACC · cold climate	ML196UH090XE48B*	15.8	10.0	8.1	37,000	218079957
TZID24H520ZACC · cold climate	S9X2C100U5PSB**	15.7	10.2	8.6	39,000	218079808
TZID24H520ZACC · cold climate	S9X1C100U5PSB**	15.7	10.2	8.6	39,000	218079774
TZID24H520ZACC · cold climate	RL18100C16MPS1	15.7	10.2	8.3	39,000	218079849
TZID24H520ZACC · cold climate	RG19100C20MPS1	15.7	9.9	8.3	39,000	218079833
TZID24H520ZACC · cold climate	RL18080C16MPS1	15.7	10.0	8.2	39,000	218079848
TZID24H520ZACC · cold climate	ML196UH090XE60C*	15.4	10.0	8.3	38,000	218079958
TZID24H520ZACC · cold climate	MGV80M100C5A	15.4	10.2	8.1	38,000	218079721
TZID24H520ZACC · cold climate	MGV96U100C5C	15.3	10.0	9.0	41,000	218079694
TZID24H520ZACC · cold climate	RG19100C16MPS1	15.3	9.9	8.3	39,000	218079832
TZID24H520ZACC · cold climate	RG19080C20MPS1	15.3	9.9	8.1	39,000	218079831
TZID60H520ZACC · cold climate	-	15.2	10.0	9.0	40,000	218043403
TZID24H520ZACC · cold climate	C120-M-V	15.2	9.8	8.9	42,000	218079706
TZID24H520ZACC · cold climate	C105-M-V	15.2	10.2	8.7	41,000	218079705
TZID24H520ZACC · cold climate	ML196UH110XE60C*	15.2	10.2	8.3	38,000	218079959
TZID24H520ZACC · cold climate	ML193UH110XE60C*	15.2	10.1	8.3	38,000	218079955

Yearly running cost in 10 large cities$1,263-$3,145

Phoenix, AZ$1,525/yr
Miami, FL$1,263/yr
Houston, TX$1,365/yr
Atlanta, GA$1,338/yr
Los Angeles, CA$1,293/yr
New York, NY$3,145/yr
Chicago, IL$2,543/yr
Denver, CO$2,106/yr
Seattle, WA$1,288/yr
Minneapolis, MN$2,603/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 TZID48H520ZCS?: The Thermal Zone TZID48H520ZCS is rated at up to 16.7 SEER2 and 10.3 EER2 for cooling and up to 9.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 37 certified matchups SEER2 ranges from 15.2-16.7.
Is the Thermal Zone TZID48H520ZCS good for cold climates?: Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 42,000 BTU/h at 5°F with a COP of 1.85, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
How much does the Thermal Zone TZID48H520ZCS cost to run per year?: At its rated efficiency it costs about $1,263-$3,145 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,525 in Phoenix and $2,603 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 TZID48H520ZCS?: ENERGY STAR lists 37 certified combinations for this outdoor unit. The highest-rated ones use TZID24H520ZACC, TZID48H520ZAM, TZID60H520ZACC.
What refrigerant does the Thermal Zone TZID48H520ZCS 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 $1,496/yrYou save $808/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 TZID48H520ZCS

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: $1,496
Current system, per year: $2,304
You save per year: $808
Payback: 21.0 years
Net after 10 years: -$8,921

Cooling $949Heating $548Electricity used: 9,350 kWhSaved vs. a minimum-efficiency heat pump: $269

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 3.5 ton models

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MRCOOL CENTRAL-48-HP-C-230B00-O · cold climate16.6 SEER2 · 9.5 HSPF2
Midea MO1BE-H48B-2A · cold climate16.7 SEER2 · 9.0 HSPF2
Capella CCB1-H48A-O · cold climate16.5 SEER2 · 9.5 HSPF2
MDV MOX630-48HFN10-M3 · cold climate16.7 SEER2 · 9.0 HSPF2
DIRECT AIR DIRM4-48MAGICPRO20-OU · cold climate16.5 SEER2 · 9.5 HSPF2
DuraSTAR DRU1U48S2A · cold climate16.7 SEER2 · 9.0 HSPF2
KERR A-KXP48SA-1 · cold climate16.5 SEER2 · 9.5 HSPF2

See all 138 3.5 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of May 1, 2026. How we use the data.