Gas water heaters are devices used in homes and buildings to provide hot water. They operate using natural gas to provide the heating combustion. Natural gas water heaters offer two main design distinctions - tank or tankless.
Tank gas water heaters
Tank model gas water heaters provide hot water through convection. This means tank design gas hot water heaters heat water in the bottom of a tank, which is filled at the bottom through a device called a dip tube. As the water heats in gas water heaters, the warmer liquid will rise to the top. This hot water is pulled off for use by a discharge pipe. Tank model gas water heaters keep a continuous supply of hot water stored.
Tank design gas water heaters are common in many homes and have been used for decades. They require routine maintenance to operate to their full potential.
Tankless gas water heaters
Tankless gas water heaters operate using the principle of flash heating. This means water in natural gas water heaters of the tankless variety operate on demand only. Tankless gas water heaters are considered more energy efficient than tank model designs. This fact has them phasing out tank heaters in many homes.