In 1948, research by R.G. Huebscher established flow resistance for different shapes of ductwork at equal velocities, which allowed the creation of the duct-sizing calculator or “Ductulator” for ...

One of our most popular catalog items! This durable two-sided plastic sizing wheel comes with a complete instruction manual for residential and commercial duct-sizing procedures. One of our most ...

Developers and owners of residential homes are generally keen on keeping heating and cooling costs as streamlined as possible without sacrificing performance. A properly sized system costs less to run ...