Irvine, Calif. — Navien’s new premium non-condensing (NPN) tankless water heaters are being installed almost as quickly as they are shipped. Currently available in a universal indoor/outdoor model (NPN-Universal) in sizes 180,000 BTU/H and 199,900 BTU/H or an exterior, outdoor only model (NPN-Exterior) in sizes 180,000 BTU/H and 199,900 BTU/H. The NPN is available for order Read more