The MAREY Power Pack 220-Volt tankless electric water heater combines the compact size to be installed almost anywhere with the power to provide endless hot water to a whole house. Its build at high quality standards to lasts many years. It is the only water heater in the market that has the ability to be wired to a 10 Amp, 20 Amp, 30 Amp or 40 Amp breaker. (By wiring the unit to a smaller breaker you are limited to the power setting you can use). The Power pack is a versatile and reliable tankless water heater that can be used either as a point of use or to supply unlimited hot water to a whole apartment or small house. It is also called water heater on demand, because it heats water only when needed, saving energy. It is designed in the USA and it's perfect to supply endless hot water for up to 1-2 points of use simultaneously, this greatly depends on your incoming water temperature and flow rate. (for a variety of residential hot-water applications). Its compact design saves space and is easy to install. It is ideal for a 1-2 bathroom house in a tropical climate. For regions with a cooler incoming temperature as found in most of the continental U.S. this would be more suited for a single point of use to achieve optimal performance. The amount of temperature increase will vary on the power setting and the flow rate of water going through the unit. Unit performance is affected if installed above 2000 feet elevation from sea level.