Gas-fired Storage Water Heater
Gas-fired storage water heaters contain a fuel-fired heating element to heat the water in the tank to be used for showers, dishwashing, and other domestic uses.
Look for the Energy Star label. Water heater performance is rated by an energy factor (EF). A minimum EF of 0.67 is required for tanks less than 55 gallons, and an EF of 0.77 is required for tanks over 55 gallons. The higher the EF, the better!
Conventional electric storage water heaters don't have particularly sustainable features.
The Romans were taking hot baths all over their empire by the year 300 AD. Typically, wood was the fuel source to heat water for public and private bathhouses.