The Rheem XG40T09HE40U0 is a robust 40-gallon tall natural gas water heater from Rheem’s Performance Plus Series, engineered to balance efficiency with enduring performance. It delivers powerful, reliable heating with a Uniform Energy Factor (UEF) of up to 0.65 (U.S.) and a generous first-hour delivery of 70–81 gallons, capable of meeting the demands of a typical 2–4 person household. 

Built for ease of maintenance and long-term durability, this model features a self-powered diagnostic gas control valve, a low-NOx eco-friendly burner, and a self-cleaning system designed to reduce sediment buildup. It also includes a premium-grade anode rod for enhanced corrosion protection and a maintenance-free burner system—no filters to clean or replace.

Safety and longevity are further reinforced with standard T&P relief valve, low-lead compliance, and high-altitude certification (up to 6,000 ft, with some models rated to 10,200 ft depending on factory options). Backing this all up is peace of mind in the form of an industry-leading 9-year limited warranty on tank and parts, plus a 2-year full in-home labor warranty.