Tankless Opperational Differences
Tankless vs. Tanks: What Are The Differences?
Tanks and Tankless units have operational differences you need to be aware of.
Typically, you can expect to use approximately 70% of a tank’s volume; i.e., a 50-gallon tank should provide approximately 35 gallons of hot water. The burner initiates to reheat the tank, but the latter can only recover at approximately 1 GPM. Thus, the recovery wait begins. This stored volume, in combination with the standing pilot light, usually results in an Energy Factor (EF) in the low range of 0.53 ~ 0.62 for gas fired, tank-type water heaters. “Energy factor is what the end user pays for. A water heater with an energy factor of 0.62 means that for every dollar spent heating water, $0.62 is being used to heat the water. The remaining $0.38 is wasted.”
Whatever the maximum flow rate for any Tankless unit that flow is continuous for as long as there is demand. And unlike a tank-type heater, the temperature remains constant at the selected set point. There is no stored water and no pilot light, so Tankless systems have a high EF range between 0.81 and 0.94, depending on the model and gas type.