6-year limited Tank warranty, 6-year parts warranty for Residential applications Flammable Vapor Resistant/Direct Vent Sealed Combustion System-Thru-the-wall/thru-the-roof venting of combustion products. Durable, Ultra-Low NOx Burner Construction Green Choice® Gas Burner -Patented eco-friendly burner design reduces NOx emissions by up to 33% and complies with Low-NOx emission requirements of less than 40 ng/J. Coregard™ Anode Rod - • Our anode rods have a stainless steel core that extends the life of the anode rod allowing superior tank protection far longer than standard anode rods. Blue Diamond® Glass Coating - Provides superior corrosion resistance compared to industry standard glass lining.