Indirect Heater Indirect Heater Dahmes Stainless, Inc. indirect heaters are designed, engineered and fabricated to the customer’s specific product and dryer application. We have our own unique obround design that’s makes our heater one of the cleanest process air streams in the business. The ultra-pure air has no contaminating air or NOx byproducts. This unique design makes our indirect heater 96% efficient. Also the heater has visual inspection as well as spray down clean ability for outside air. For more details about our indirect heater, please contact us at Dahmes Stainless, Inc.