Tankless water heaters

Tankless water heaters heat water instantaneously without the use of a storage tank. When a hot water faucet is turned on, cold water flows through a heat exchanger in the unit, and either a natural gas burner or an electric element heats the water. As a result, tankless water heaters deliver a constant supply of hot water. You don't need to wait for a storage tank to fill up with enough hot water. However, a tankless water heater's output limits the flow rate.

Typically, tankless water heaters provide hot water at a rate of 2–5 gallons (7.6–15.2 liters) per minute. Gas-fired tankless water heaters produce higher flow rates than electric ones. Sometimes, however, even the largest, gas-fired model cannot supply enough hot water for simultaneous, multiple uses in large households. For example, taking a shower and running the dishwasher at the same time can stretch a tankless water heater to its limit. To overcome this problem, you can install two or more tankless water heaters. You can also install separate tankless water heaters for appliances -- such as a clothes washer or dishwater -- that use a lot of hot water in your home. However, additional water heaters will cost more and may not be worth the additional cost.