The GT-340-PIH offers high efficiency Ultra-Low NOx condensing technology allowing for the use of 3" PVC venting and has 0" clearance to combustibles. Utilizing HRS35 copper alloy for the heat exchanger tubing. Remote control included as a standard feature. Indoor models are certified up to 10,100 ft. altitude. ENERGY STAR® qualified 15-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Residential applications Copper Primary Heat Exchanger Stainless Steel 316L Secondary Heat Exchanger Complies with Ultra-Low NOx regulations of less than 14 ng/J (<20ppm) Condensing Outdoor model Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes