Eccotemp delivers what you need, at a price point that you can afford. The Eccotemp 45H-NG thankless water heater in a Natural Gas Outdoor installed 6.8 GPM thankless water heater. Eccotemp 45H-NG thankless water heater is the ideal choice for a typical 3 bedroom, two bath home. Eccotemp Thankless water heaters are the ideal way to heat water with gas. Average savings are approximately 20% off of your gas bill. With an outdoor installation, there is no additional vent piping to purchase. Flow Rate: 35 degree rise: 6.0 GPM 45 degree rise: 4.57 GPM 77 degree rise: 2.6 GPM Energy Factor: 0.82.