Tankless water heaters heat water on demand, eliminating the storage tank. They reduce the energy consumption required to maintain the temperature of large volumes of water. The flow of water through the unit causes it to ignite a gas flame or electric heating element to heat the liquid to the set temperature.
The amount of energy conservation of a tankless unit depends on the household demand for hot water. In homes using less than 41 gallons daily, the savings ranges from 24 to 34 percent when compared to a storage tank. In homes using more hot water, the savings drops to 8 to 14 percent. However, installing several smaller units near the point of use increases the overall savings to as high as 50 percent.
Most tankless water heaters report a life expectancy of 20 years or longer, but the initial investment is more. The longer life, combined with the energy savings, helps to balance the initial higher cost.
Some gas units use a standing pilot, while others use an igniter. With the standing pilot, the consumer should consider the gas it consumes when comparing energy savings. Igniter models eliminate this energy use.
Manufacturers of tankless water heaters usually suggest a maintenance schedule in the owner’s manual. Following this schedule provides a significant improvement in the life of the unit.