The Eccotemp 40HI-NG is basically recognized as the indoor equal of the Eccotemp 40H tankless water heater. The Eccotemp 40HI-NG is meant to supply hot water to a traditional three-bedroom, two-bathroom residence. This tankless water heater is an right choice for retrofitting your old storage tank heater, or can be plumbed in a new location. Additionally, the Eccotemp 40HI-NG is powered by natural gas which essentially leads to a lower operating cost than comparable electric units and possesses an energy factor (EF) of 0.82. Rated at an already amazing 6.3 GPM, this unit is also split system changeable, which can further enhance effectiveness and hot water delivery speed. With built-in pressure relief filter system and a 10-year warranty, this tankless hot water heater is definitely the perfect choice for a standard sized residence.