Although our direct-fired gas heater provides a very clean heat source, certain applications require 100% clean, heated air. Electric heaters offer 100% clean air, but they require a large power source. NuTemp offers indirect-fired heaters to provide a clean heat source with minimal power requirements. Indirect-fired heaters use a secondary heat exchanger to separate the breathable air stream from the combustion air stream. NuTemp offers various units with either propane gas, natural gas or diesel as the fuel source. Call for details and specifications.