What is a fast water heater?

A fast water heater, sometimes called a tankless water heater, heats water on demand as it flows through the unit instead of maintaining a reservoir of water at temperature. These heaters can be more efficient than conventional water heaters, but can be expensive and may provide inconsistent temperatures.

While a fast water heater can reduce the amount of energy needed to maintain a hot water supply, the savings can be negligible compared to the cost of installing one of these units. If the unit uses gas, it may require expensive upgrades to a home's gas supply. In some cases, the amount of money saved per month may not offset the cost of the unit over its projected lifespan.