Tankless water heaters heat water entirely on demand, only when it is needed. When a hot water faucet is turned on and the water begins to flow, a sensor detects that hot water is being demanded. The start-up process takes a couple of seconds. In sophisticated systems like the Tempra electric tankless water heater, sensors constantly monitor incoming water temperature and water flow rates and adjust the power output of the heating elements to maintain a precise output temperature as set by the homeowner. This is often referred to as "flow-modulation" although it is probably more accurately described as flow-based power modulation.
The tankless water heater will remain on until the hot water faucet is turned off. As soon as the flow sensor detects that water has stopped flowing, the power to the unit is turned off completely. So when hot water is not being demanded, absolutely no energy is being consumed.The stand-by heating loss is completely eliminated.
Furthermore, since a tankless water heater has no refresh rate (it is instantaneous), there is no need to overheat the water to 130 or 140°F (or higher) as with a conventional tank. You can select an output temperature that matches your actually needs (usually about 105-110°F). This also saves considerable energy. For each 10°F reduction in water temperature, the U.S. Department of Energy estimates that you can save between 3%-5% in energy costs.
Being about the size of a briefcase (in the case of an electric tankless water heater), considerable space savings are also achieved. As a result, tankless water heaters can often be installed closer to the point-of-use, delivering hot water to the faucet faster. The extra space can be employed for storage, etc.
Tankless water heaters have far longer service lives than traditonal tank type heaters. Since there is no storage of heated water, they tend to be far less prone to hard water scale problems and since they maintain strong water pressure at all times, sediments do not settle out of the water and collect in the heater - they are washed right through.
When considering an electric tankless water heater, there is certain electrical requirement that must be met. During our visit we will review those requirements, so you can make an informed decision.
**information provided above is taken from Tempera’s website***