Q: How does a tankless water heater work?

A: Unlike a traditional water heater with a storage tank, a tankless unit operates only when hot water is needed for an appliance or hot-water-using fixture, such as a shower or tub. Demand for hot water triggers the water heater to fire its gas/propane burner or electric coils to heat water as it travels through coils. Without a tank, the unit rarely runs out of hot water and there is no "recovery time" as with a tank unit when hot water is not available.