NPE-A series condensing tankless water heaters from Navien are ideal for both commercial and residential applications. They have 1/2-inch gas pipe capability, 2-inch PVC venting, dual stainless steel heat exchangers, ComfortFlow recirculation including pump and buffer tank, field gas convertibility, and an elegant compact design. Up to 16 units can be cascaded together without an external control, and eight units may be common vented. Highly efficient at 0.97 EF or 0.96 UEF, NPE-180A, NPE-210A and NPE-240A are also available with on-demand activation and NaviLink Wi-Fi control. 800-519-8794; www.tanklessmadesimple.com.