HVAC Rated

3-ton central heat pump · DRU Series

DuraSTAR DRU1U36S2A

Average cooling and heating efficiency for a 3-ton central heat pump, and certified for cold climates.

Ranks #184 of 302 3 ton central heat pumps for cooling efficiency, and costs about $1,064 a year to run in a mixed climate like Atlanta.

SEER2
16.7 Cooling efficiency over a season
Average · beats 43%
HSPF2
9.3 Heating efficiency over a season
Average · beats 62%
EER2
10.2 Cooling efficiency on a 95°F day
Below average · beats 15%
Heat at 5°F
29,200 BTU/h79% of its 47°F output
Below average · beats 39%

A good fit if…

  • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 29,200 BTU/h at 5°F.
  • You want steady temperatures and quiet running - the compressor varies its speed.
  • You want a choice of indoor units - 13 certified pairings.

Think twice if…

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

Calculate my running cost

Details

Specifications3 ton, R-454B
General
BrandDuraSTAR
Outdoor unit modelDRU1U36S2A
SeriesDRU Series
TypeCentral heat pump
Nominal size3 ton
CompressorVariable-speed units run longer at low powerContinuously variable
RefrigerantR-454B
Connected (smart) capableNo
On the market sinceDecember 8, 2020
Last certifiedMay 1, 2026
Cooling
SEER2Seasonal efficiency, higher is better16.7 (range 15.2-16.7)
EER2Efficiency at 95°F outdoors9.3-10.2
Cooling capacity35,000-36,000 BTU/h
Heating
HSPF2Seasonal efficiency, higher is better8.1-9.3
Capacity at 47°F35,000-37,000 BTU/h
Capacity at 17°F23,000-27,000 BTU/h
Capacity at 5°F26,000-29,200 BTU/h
COP at 5°F2.0 = twice as efficient as a space heater1.80-2.00
ENERGY STAR cold climateYes
Heating output as it gets colder79% kept at 5°F

Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with DRUF3622S2A at the standard test temperatures, in BTU/h:

Certified matchups13 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 unitFurnaceSEER2EER2HSPF2Heat @5°FAHRI ref.
DRUF3622S2A · cold climate-16.710.29.329,200217285078
DRUM3036S2A · cold climate-16.110.08.727,000215374895
DRUC3621S2A · cold climateRL18100C20MPS115.710.18.526,000218072085
DRUC3621S2A · cold climateS9V2C100U5VS***15.69.98.526,000218071873
DRUC3621S2A · cold climateS9V2C100D5VS***15.69.98.526,000218071872
DRUC3621S2A · cold climateRL18100C16MPS115.610.08.426,000218072084
DRUC3621S2A · cold climateRL18080C16MPS115.69.68.326,000218072083
DRUC3621S2A · cold climateML296UH110XV60C*15.59.98.526,000218072300
DRUC3617S2A · cold climateRL18080B12MPS115.49.38.226,000218072082
DRUC3617S2A · cold climateMGV96U060B3C15.49.58.226,000218071731
DRUC3621S2A · cold climateRG19080C16MPS115.49.58.126,000218072028
DRUC3621S2A · cold climateS9V2C080U5VS***15.39.88.626,000218071871
DRUC3617S2A · cold climateRG19080B12MPS115.29.38.427,000218072027
Yearly running cost in 10 large cities$1,010-$2,496

At each state's average electricity price and the city's typical heating and cooling hours.

Questions5
What is the SEER2 rating of the DuraSTAR DRU1U36S2A?
The DuraSTAR DRU1U36S2A is rated at up to 16.7 SEER2 and 10.2 EER2 for cooling and up to 9.3 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 13 certified matchups SEER2 ranges from 15.2-16.7.
Is the DuraSTAR DRU1U36S2A good for cold climates?
Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 29,200 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 DuraSTAR DRU1U36S2A cost to run per year?
At its rated efficiency it costs about $1,010-$2,496 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,217 in Phoenix and $2,063 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 DuraSTAR DRU1U36S2A?
ENERGY STAR lists 13 certified combinations for this outdoor unit. The highest-rated ones use DRUF3622S2A, DRUM3036S2A, DRUC3621S2A.
What refrigerant does the DuraSTAR DRU1U36S2A 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 $1,192/yrYou save $664/yrSee details ↓
1. Where you live
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.

2. The heat pump DuraSTAR DRU1U36S2A
3. What it replaces
4. Price replace the example with your quote
Heat pump, per year
$1,192
Current system, per year
$1,856
You save per year
$664
Payback
20.3 years
Net after 10 years
-$6,861

Cooling $759Heating $434Electricity used: 7,452 kWhSaved vs. a minimum-efficiency heat pump: $231

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