Point-of-Use or Whole-House

• Whole-house tankless water heaters have a relatively high capacity (2 to 5 gallons per minute) and are designed to provide hot water to entire house from a central location.
• Point-of-use tankless water heaters are relatively low capacity and are design to heat enough water for one or two fixtures. They are used when hot water is needed a distance from a residence's central water heater (a shower in a bath house, a sink in a guest house).

Fuel: Natural Gas, Propane, or Electric

• Natural gas is the most common fuel used for tankless water heaters. It heats water quickly and efficiently. To be able to use a natural gas tankless water heater, natural gas has do be available to homes on your street. If you already have gas appliances in your home, running the gas to the new water heater should be straightforward. If gas is available on your street but you are not yet connected, you will need to have your plumber coordinate with the utility company to run a line into your house. This job usually requires a permit and the work needs to approved by an inspector. You will need to vent the by-products of combustion safely from your home.

• Propane heats water quickly and efficiently like natural gas. However, unlike natural gas, propane is stored in a tank on your property. Rural homeowners frequently use propane because they do not often have natural gas service but they do have the space to store a propane tank.

• Electric tankless water heaters do not heat water as quickly as gas water heaters, which makes them ill-suited to be a central water heater functioning as the primary source of hot water in a home. Electric tankless water heaters can function well in some other configurations.