What is the SEER2 rating of the Grandaire W5H5S18*K*AAA?

The Grandaire W5H5S18*K*AAA is rated at up to 15.5 SEER2 and 12.5 EER2 for cooling and up to 8.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 48 certified matchups SEER2 ranges from 15.2-15.5.

Is the Grandaire W5H5S18*K*AAA 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 Grandaire W5H5S18*K*AAA cost to run per year?

At its rated efficiency it costs about $548-$1,392 a year in electricity in large U.S. cities, depending on climate and local rates - for example $665 in Phoenix and $1,155 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 Grandaire W5H5S18*K*AAA?

ENERGY STAR lists 48 certified combinations for this outdoor unit. The highest-rated ones use FMA5X24**AL, W5VM32M17XA, FM(C,U)5Z18**AL.

1.5-ton central heat pump · 15 SEER2 HP

Grandaire W5H5S18KAAA

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

Ranks #142 of 170 1.5 ton central heat pumps for cooling efficiency, and costs about $589 a year to run in a mixed climate like Atlanta.

SEER2: 15.5 Cooling efficiency over a season
Below average · beats 15%
HSPF2: 8.0 Heating efficiency over a season
Below average · beats 12%
EER2: 12.5 Cooling efficiency on a 95°F day
Very good · beats 80%
Heat at 5°F: 8,600 BTU/h46% of its 47°F output
Average · beats 58%

A good fit if…

You want a choice of indoor units - 48 certified pairings.

Think twice if…

You often see nights below 0°F - it is not cold-climate certified.
Cooling cost matters most - its SEER2 is below average for central heat pumps.
You mainly need heat - its HSPF2 is below average for central heat pumps.
Comfort and noise matter - a single-stage compressor runs only full-on or off.

Calculate my running cost

Details

Specifications1.5 ton, R-454B

General
Brand	Grandaire
Also sold as	ECOTEMP
Outdoor unit model	W5H5S18KAAA
Series	15 SEER2 HP
Type	Central heat pump
Nominal size	1.5 ton
CompressorVariable-speed units run longer at low power	Single stage
Refrigerant	R-454B
Connected (smart) capable	No
On the market since	July 1, 2022
Last certified	June 29, 2026
Cooling
SEER2Seasonal efficiency, higher is better	15.5 (range 15.2-15.5)
EER2Efficiency at 95°F outdoors	11.7-12.5
Cooling capacity	17,400-18,900 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better	7.8-8.0
Capacity at 47°F	16,400-18,300 BTU/h
Capacity at 17°F	10,500-11,000 BTU/h
Capacity at 5°F	8,200-8,600 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater	1.88-2.10
ENERGY STAR cold climate	No

Heating output as it gets colder46% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with FMA5X24**AL at the standard test temperatures, in BTU/h:

Certified matchups48 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.
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423945
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423946
W5VM32M17XA	WFE070B048C	15.5	12.0	7.8	8,200	214195493
W5VM32M17XA	WFE070B048C	15.5	12.0	7.8	8,200	214195492
W5VM32M17XA	WFE070B036C	15.5	12.0	7.8	8,200	214195460
W5VM32M17XA	WFE070B036C	15.5	12.0	7.8	8,200	214195461
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828805
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828806
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828837
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828838
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452539
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452538
W5A*25M17XA	WFE045A036C	15.2	12.0	7.8	8,400	214126110
W5A*25M17XA	WFE045A036C	15.2	12.0	7.8	8,400	214126111
W5A*25M17XA	WFET045A036A*	15.2	12.0	7.8	8,400	214126697
W5A*25M17XA	WFET045A036A*	15.2	12.0	7.8	8,400	214126698
W5A*25M17XA	WFET070A036A*	15.2	12.0	7.8	8,400	214126709
W5A*25M17XA	WFET070A036A*	15.2	12.0	7.8	8,400	214126710
W5A*25M17XA	WFE070A036C	15.2	12.0	7.8	8,400	214126170
W5A*25M17XA	WFE070A036C	15.2	12.0	7.8	8,400	214126171
W5A*25M17XA	WFE070B036C	15.2	12.0	7.8	8,400	214126200
W5A*25M17XA	WFE070B036C	15.2	12.0	7.8	8,400	214126201
W5A*25M17XA	WFE070B048C	15.2	12.0	7.8	8,500	214126232
W5A*25M17XA	WFE070B048C	15.2	12.0	7.8	8,500	214126233
W5A*25M17XA	WFE090B042C	15.2	12.0	7.8	8,400	214126264
W5A*25M17XA	WFE090B042C	15.2	12.0	7.8	8,400	214126265
W5A*25M17XA	WFAX080B048B*	15.2	12.0	7.8	8,400	214127040
W5A*25M17XA	WFAX080B048B*	15.2	12.0	7.8	8,400	214127041
W5A*25M17XA	WFAX060B042B*	15.2	12.0	7.8	8,400	214127008
W5A*25M17XA	WFAX060B042B*	15.2	12.0	7.8	8,400	214127009
W5A*25M17XA	WFEU040B036A*	15.2	12.0	7.8	8,400	214126423
W5A*25M17XA	WFEU040B036A*	15.2	12.0	7.8	8,400	214126424
W5A*25M17XA	WFEU040B036B*	15.2	12.0	7.8	8,400	214126487
W5A*25M17XA	WFEU040B036B*	15.2	12.0	7.8	8,400	214126488
W5A*25M17XA	WFSX080B048B*	15.2	11.7	7.8	8,500	214127104
W5A*25M17XA	WFSX080B048B*	15.2	11.7	7.8	8,500	214127105
W5A*25M17XA	WFEU060B048B*	15.2	12.0	7.8	8,400	214126519
W5A*25M17XA	WFEU060B048B*	15.2	12.0	7.8	8,400	214126520
W5A*25M17XA	WFSU060B048B*	15.2	12.0	7.8	8,500	214127213
W5A*25M17XA	WFSU060B048B*	15.2	12.0	7.8	8,500	214127214
W5A*25M17XA	WFST060B048A*	15.2	11.7	7.8	8,400	214127358
W5A*25M17XA	WFST060B048A*	15.2	11.7	7.8	8,400	214127359
WCHL305*B	-	15.2	12.0	7.8	8,400	214179583
WCHL305*B	-	15.2	12.0	7.8	8,400	214179584
FMA5X18**AL	-	15.2	12.0	7.8	8,200	214423913
FMA5X18**AL	-	15.2	12.0	7.8	8,200	214423914
FM(C,U)5Z30**AL	-	15.2	12.0	7.8	8,200	215828869
FM(C,U)5Z30**AL	-	15.2	12.0	7.8	8,200	215828870

Yearly running cost in 10 large cities$548-$1,392

Phoenix, AZ$665/yr
Miami, FL$548/yr
Houston, TX$596/yr
Atlanta, GA$589/yr
Los Angeles, CA$570/yr
New York, NY$1,392/yr
Chicago, IL$1,127/yr
Denver, CO$934/yr
Seattle, WA$572/yr
Minneapolis, MN$1,155/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 Grandaire W5H5S18*K*AAA?: The Grandaire W5H5S18*K*AAA is rated at up to 15.5 SEER2 and 12.5 EER2 for cooling and up to 8.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 48 certified matchups SEER2 ranges from 15.2-15.5.
Is the Grandaire W5H5S18*K*AAA 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 Grandaire W5H5S18*K*AAA cost to run per year?: At its rated efficiency it costs about $548-$1,392 a year in electricity in large U.S. cities, depending on climate and local rates - for example $665 in Phoenix and $1,155 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 Grandaire W5H5S18*K*AAA?: ENERGY STAR lists 48 certified combinations for this outdoor unit. The highest-rated ones use FMA5X24**AL, W5VM32M17XA, FM(C,U)5Z18**AL.
What refrigerant does the Grandaire W5H5S18*K*AAA 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 $655/yrYou save $267/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 Grandaire W5H5S18*K*AAA

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: $655
Current system, per year: $922
You save per year: $267
Payback: 26.2 years
Net after 10 years: -$4,328

Cooling $411Heating $244Electricity used: 4,092 kWhSaved vs. a minimum-efficiency heat pump: $51

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 1.5 ton models

Carrier GH5SAN518**AA15.5 SEER2 · 8.0 HSPF2
Heil B5H6S18*K*AAA15.5 SEER2 · 8.0 HSPF2
Carrier 27SCA518A**3015.5 SEER2 · 8.0 HSPF2
Heil H5H6S18*K*AAA15.5 SEER2 · 8.0 HSPF2
Bryant PH5SAN518**AA15.5 SEER2 · 8.0 HSPF2
Heil N5H5S18*K*AAA15.5 SEER2 · 8.0 HSPF2
York YH518E2S1116.0 SEER2 · 7.8 HSPF2
Tempstar T5H6S18*K*AAA15.5 SEER2 · 8.0 HSPF2

See all 170 1.5 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 29, 2026. How we use the data.