A tankless water heater responds directly to your demand for hot water. When you turn on a tap or shower, the tankless water heater is aware of the demand and engages its heating elements.

In simple hydro-mechanical units like the AQM and AQC, it is the flow of water that physically engages a silent switch to turn on the heating elements. These are simple on-off units, but when sized properly will deliver the desired water temperature consistently with exceptional reliability. Due to the lack of a microprocessor, these units are only able to service a single point-of-use safely.

For advanced units like the AQE and DHE, an onboard microprocessor in the electronic control module analyzes data from the flow sensor (flow rate) and the incoming temperature sensor. This determines how much power is necessary to get the amount of water flowing through the unit up to the temperature you select on the dial. The unit will then apply just enough power to meet the demand, no more. In addition to decreasing electricity usage, this also increases the reliability and life span of the unit.

Because the incoming temperature sensor is constantly feeding data into the microprocessor, the AQE and DHE can instantaneously react to temperature fluctuations. They apply more or less power as necessary to keep water temperature consistent and comfortable for as long as there is a need. This also means that these units are able to supply hot water to multiple draw points and can react instantly when demand suddenly changes.

How Tankless Works Tank vs. Tankless Hot or Warm Water? Energy Efficiency