The FVIR compliant ProLine direct vent Gas Water Heater is to designed to draw air from outside the home, eliminating problem caused by insufficient indoor ventilation. The unit has horizontal air intake and venting on all model up to 80 in from the outside wall with no electrical power needed. Featuring a 50 gal (nominal) tank and a 47000 Btu/hr gas burner, the GS6-50-YRDS power vent deliver a first hour rating of 83 gal. With an 0.65 Uniform ENERGY FACTOR, this water heater is not ENERGY STAR certified. It carries a 6 years limited warranty and meet Low NOx emission requirement.