Point of use water heater
Tankless hot water heater
Like with all tankless units, a point of use water heater provides an instant supply of hot water. However these tankless hot water heaters are designed to service a particular fixture or adjacent fixtures, alleviating the work load of a primary water heater.
Using these units in conjunction with a whole house tankless water heater or storage tank unit can improve efficiency. You can turn down the temperature setting significantly and allow the point of use unit to serve as a booster only for those fixtures that demand higher water temperatures.
There are several possibile applications, but in general point of use water heaters are more effective if there installed in areas that are relatively far removed from a home's primary water heating source. These units are typically very small, so they can be installed almost anywhere indoors.
Single point application
A single point application is designed to service the needs of a certain hot water consuming fixture. For example a point of use unit can be installed to service a particular hot water consuming appliance (dishwasher or washing machine) or a kitchen sink.
With this application the unit is installed directly by the fixture or appliance.
Multi point or flow control application
A multi point application can be used to service the needs of two or more hot water consuming fixtures. It's important to note that for this application the fixtures and their plumbing must be adjacent to one another.
A good example for this application would be a particular bathroom or an entire kitchen, if flow rates permit.
Thermostatically controlled tankless units make ideal backups to solar hot water heaters. They factor in the incoming water temperature and heat only as needed in order to reach the wanted outgoing water temperature.
This application is designed to serve as both an instant supply and temperature booster. These instant hot water heaters are also used in conjunction with storage tank units, to service fixtures that suffer temperature loss from long pipe lines.
With this application point of use units are installed on the plumbing lines and between the primary sources and the fixtures in the far removed areas.
Flow rates and climate region
Just like with all tankless hot water heaters, the flow rates of the consuming fixtures in question and the regional climate are essential considerations that should be seriously made in order to choose the best tankless water heater.
More on tankless hot water heaters