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All About Water Heaters

Plumbing and heating expert Richard Trethewey walks through all the various options available to homeowners for purchasing or renting a water heater.

In this video, Ask This Old House plumbing and heating expert Richard Trethewey walks through all the various options available to homeowners for purchasing or renting a water heater.

Types of Water Heaters

Gas Storage Tank Water Heater

  • Gas burner is underneath the tank. Cold water enters the glass-lined tank by the dip tube and goes to the bottom of the tank. Through the process of convention, hot water rises to the top of the tank.
  • A flue runs through the tank and up out of the house to take away exhaust gases.
  • Most popular in the USA

Electric Storage Tank Water Heater

  • The process is very similar to the gas water heater. A dip tube brings cold water to the bottom of the tank, where it is heated.
  • There is no direct burner, but there are electric elements to heat the water, just like in a coffee machine.
  • There is no gas, so there is no need for a flue.
  • Usually more expensive to run than a gas water heater.

Hybrid Water Heater

  • A heat pump heats the water in the tank. It works as an air conditioner does - it moves heat from one location to another. It pulls heat from the surrounding air and, through fans and coils, heats that air even more, then dumps it into a tank to heat water.
  • It can be two to three times more energy-efficient than conventional electric resistance water heaters.
  • They work best in a warmer climate.

Tankless Water Heater

  • Also known as “instantaneous” or “on-demand” because they make hot water only when you need it.
  • When the hot water tap is turned on, cold water travels through a pipe into the tankless heater. A heating element (usually a gas burner or sometimes an electric element) heats the water as it travels through the tank.
  • Popular in Asia and most of Europe. They are starting to gain popularity in the USA.

Indirect Water Heater

  • It has no direct flame. It relies on a boiler or furnace to produce its heat. It is typically a stainless steel-lined tank that holds a coiled heat exchanger. Boiler water is pumped into the coil through a pipe that connects the units. The coil transfers the heat into the water in the tank. The water from the boiler never mixes with the water in the tank.
  • You’ll need to have a boiler in your home for this type of water heater.

Resources

Richard explains the different types of hot water heaters you can install in your home: gas storage tank water heater, electric storage-tank water heater, hybrid tank water heater, tankless water heater, and indirect water heater.

Water heaters can be purchased at home centers or sourced through a local HVAC technician or sales representative.

Viessman Manufacturing manufactured the hybrid water heater.