What is the SEER2 rating of the Heil N5H5S18*K*AAA?

The Heil N5H5S18*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 505 certified matchups SEER2 ranges from 15.2-15.5.

Is the Heil N5H5S18*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 Heil N5H5S18*K*AAA cost to run per year?

At its rated efficiency it costs about $548-$1,398 a year in electricity in large U.S. cities, depending on climate and local rates - for example $666 in Phoenix and $1,161 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.

Is the Heil N5H5S18*K*AAA the same as the Heil R5H5S18*K*AAA?

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 Heil N5H5S18*K*AAA?

ENERGY STAR lists 505 certified combinations for this outdoor unit. The highest-rated ones use FMA5X24**AL, EVM5X32M17A, FM(C,U)5Z18**AL.

1.5-ton central heat pump · PERFORMANCE 16 SEER2 HP

Heil N5H5S18KAAA

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

Ranks #145 of 170 1.5 ton central heat pumps for cooling efficiency, and costs about $591 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 - 505 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	Heil
Also sold as	Airquest, Arcoaire, Comfortmaker, Day & Night, Keeprite, Tempstar, Kenmore, ACIQ, Smart Comfort, MARATHERM
Outdoor unit model	N5H5S18KAAA
Series	PERFORMANCE 16 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	July 16, 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 matchups505 indoor units

The same outdoor unit scores differently with each indoor unit and furnace. The 60 highest-rated of 505 are shown. 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	214423925
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423927
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423929
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423931
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423933
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423935
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423937
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423939
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423941
FMA5X24**AL	-	15.5	12.5	8.0	8,200	214423943
FMA5X24**AL	-	15.5	12.5	8.0	8,200	216630607
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195474
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195476
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195478
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195480
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195482
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195484
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195486
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195488
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195490
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195442
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195444
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195446
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195448
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195450
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195452
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195454
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195456
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	214195458
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	214195472
EVM5X32M17A	80MS(N,L)0701712A	15.5	12.0	7.8	8,200	216629729
EVM5X32M17A	80MS(N,L)0701716A	15.5	12.0	7.8	8,200	216629731
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828785
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828787
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828789
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828791
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828793
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828795
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828797
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828799
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828801
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	215828803
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828817
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828819
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828821
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828823
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828825
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828827
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828829
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828831
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828833
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	215828835
FM(C,U)5Z18**AL	-	15.2	12.0	8.0	8,500	216635212
FM(C,U)5Z24**AL	-	15.2	12.0	8.0	8,500	216635214
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452536
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452534
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452532
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452530
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452528
FM(C,U)5S30**AL	-	15.2	12.0	8.0	8,600	218452526

Same unit, other model numbers1

These model numbers have exactly the same certified ratings and matchups as the Heil N5H5S18*K*AAA: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

Heil R5H5S18*K*AAA

Yearly running cost in 10 large cities$548-$1,398

Phoenix, AZ$666/yr
Miami, FL$548/yr
Houston, TX$597/yr
Atlanta, GA$591/yr
Los Angeles, CA$573/yr
New York, NY$1,398/yr
Chicago, IL$1,132/yr
Denver, CO$939/yr
Seattle, WA$575/yr
Minneapolis, MN$1,161/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 Heil N5H5S18*K*AAA?: The Heil N5H5S18*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 505 certified matchups SEER2 ranges from 15.2-15.5.
Is the Heil N5H5S18*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 Heil N5H5S18*K*AAA cost to run per year?: At its rated efficiency it costs about $548-$1,398 a year in electricity in large U.S. cities, depending on climate and local rates - for example $666 in Phoenix and $1,161 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
Is the Heil N5H5S18*K*AAA the same as the Heil R5H5S18*K*AAA?: 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 Heil N5H5S18*K*AAA?: ENERGY STAR lists 505 certified combinations for this outdoor unit. The highest-rated ones use FMA5X24**AL, EVM5X32M17A, FM(C,U)5Z18**AL.
What refrigerant does the Heil N5H5S18*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 $656/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 Heil N5H5S18*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: $656
Current system, per year: $923
You save per year: $267
Payback: 26.2 years
Net after 10 years: -$4,326

Cooling $411Heating $245Electricity used: 4,100 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

Tempstar T5H6S18*K*AAA15.5 SEER2 · 8.0 HSPF2
WeatherMaker PH5SAN518**AB15.5 SEER2 · 8.0 HSPF2
Grandaire W5H5S18*K*AAA15.5 SEER2 · 8.0 HSPF2
DETTSON MHD-18 · cold climate15.2 SEER2 · 9.5 HSPF2
Carrier GH5SAN518**AA15.5 SEER2 · 8.0 HSPF2
Ameristar E4HL5018A1000A · cold climate15.2 SEER2 · 8.5 HSPF2
Carrier 27SCA518A**3015.5 SEER2 · 8.0 HSPF2
TCL THH18HAI2NAF2U23 · cold climate15.2 SEER2 · 8.5 HSPF2

See all 170 1.5 ton central heat pumps, ranked

Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of July 16, 2026. How we use the data.