Navien-032414-body.jpgNavien’s new NPE-S series condensing tankless water heaters have a rated efficiency of 0.98EF. The company claims the series is ideal for commercial and residential water heating applications and is available in three models with maximum inputs from 150,000 to 199,900 Btuh and maximum flow rates from 8.4 to 11.1 gpm. NPE-S units can be cascaded together, up to 16 units, without an external control box. Other features include 0.5-in gas pipe capability up to 24 ft, 2-in PVC venting up to 60 ft, dual stainless steel heat exchangers, field gas convertibility, and a compact design.