NPF700-060U3BH NPF Variable Speed Hydro-Furnace, Upflow, 60,000 BTU/hr Input, 3.5 Ton, AFUE 97%, 120V

In conventional gas furnaces the combustion heat exchanger is located in the conditioned airstream. This exposes the air to very high temperatures that can dry out the air. The NPF Difference: The NPF heats water by burning the gas in a sealed combustion heat exchanger, completely isolated from the airstream. The heated water is then pumped through a hydronic heat exchanger that gently transfers the heat into the air. This unique method improves operational control, provides safe and even heating, and keeps operating sounds to a minimum. By exposing the air to much lower temperatures, there is less impact on the conditioned air humidity level.