ENERGY STAR Program Requirement…
https://www.energystar.gov/ia/partners/prod_development/new_specs/downloads/water_heaters/WaterHeater_ProgramRequirements_2008.pdf
The exact terms of the limited warranty, given the minimum requirements, shall be determined by the PARTNER. Qualifying Products: The following residential water heater product classes are eligible for ENERGY STAR: A nominal input of 75,000 BTU/hour or less and a rated storage volume from 20 to 100 gallons. Uniform Energy Factor: UEF ≥ 3.30 for Integrated HPWH, UEF ≥ 2.20 for Integrated HPWH, 120 Volt / 15 Amp Circu, and UEF ≥ 2.20 for Split System HPWH. First Hour Rating: FHR ≥ 45 gallons per hour.
Uniform Energy Factor: UEF ≥ 3.30 for Integrated HPWH, UEF ≥ 2.20 for Integrated HPWH, 120 Volt / 15 Amp Circu, and UEF ≥ 2.20 for Split System HPWH.
First Hour Rating: FHR ≥ 45 gallons per hour.
DA: 35 PA: 75 MOZ Rank: 61