As of 2015, the top three water heaters are the Whirlpool N40S61-403, the Rheem Fury 22V40F1 and the Ecosmart ECO 27, according to consumersearch.com. The Whirlpool and Rheem models both have a 40-gallon capacity.
The Whirlpool gas water heater offers good efficiency and is suitable for average household use. Although the unit is not Energy Star approved, it gets high marks for its 6-year warranty and use of natural gas, which can potentially reduce energy bills. The Whirlpool is easy to install, but has some durability issues.
The Rheem Fury natural gas heater offers excellent durability and good efficiency, also without being Energy Star compliant. Owners of this unit have reported energy savings of at least $100 per month. The model is considered budget-priced, but has features common with more high-priced models, such as a brass drain valve, enhanced rust protection and sediment reduction.