Conventional Tank Water Heater
A single-family storage water heater offers a ready reservoir — from 20 to 80 gallons — of hot water. It operates by releasing hot water from the top of the tank when you turn on the hot water tap. To replace that hot water, cold water enters the bottom of the tank, ensuring that the tank is always full. Conventional storage water heater fuel sources include natural gas, propane, fuel oil, and electricity. Learn more about fuel types available when selecting a new water heater.
Since water is constantly heated in the tank, energy can be wasted even when a hot water tap isn’t running. This is called standby heat loss. Only tankless water heaters — such as demand-type water heaters and tankless coil water heaters — avoid standby heat losses. Some storage water heater models have heavily insulated tank, which significantly reduce standby heat losses and lower annual operating costs. Look for models with tanks that have a thermal resistance (R-Value) of R-12 to R-25.
Gas and oil water heaters also have venting-related energy losses. Two types of water heaters — a fan-assisted gas water heater and an atmospheric sealed-combustion water heater — reduce these losses. You might also want to consider some less conventional storage water heaters — heat pump water heaters and solar water heaters. These water heaters are usually more expensive but they typically have lower annual operating costs.