Available in Upflow and Horizontal configurations, the NPF comes in two sizes of 60,000 Btu/h and 100,000 Btu/h that both boast 97.0% AFUE and meet the stringent requirements of SCAQMD rule 1111 for Ultra-Low NOx performance. The NPF uses Navien’s dual stainless steel heat exchangers to heat water in an isolated compartment out of the airstream which provides sound-reduction and energy efficiency. The heated water is circulated through a hydronic coil which transfers the heat into the airstream for the ultimate in quiet forced-air heating comfort. The NPF features industry-leading variable capacity that can modulate down to 15% for an unparalleled level of comfort that allows the unit to meet year-round heating needs, the company says.