Air Distribution Systems
Our Chief of Engineering, Dr. Michael R. Busby, says “the ‘heart’ of any HVAC system is the space conditioning unit itself.” Much attention, time and effort have been given to the “heart” by the equipment manufacturers, e.g. vastly improved cooling efficiencies (SEER) and heating performance (HSPF and AFUE), environmentally-friendly refrigerants and multi-speed fans and compressors. But, alas, for decades the importance of the design, installation, and performance of the “veins and arteries”, the HVAC duct system, has essentially been ignored. Specifically, architects generally leave no room for the unsightly ductwork, owners recoil in disdain if “furr-ins” are mentioned, plumbers must have their space since it is a given that waste must have its path to leave the structure, etc. Most HVAC contractors will agree with this statement from the building contractor: “The other subs must have their spaces. You boys run your ducts wherever you can.”
It is interesting to note, however, the moment the new owner turns the HVAC unit on and there are hot and cold spots throughout the structure, the finger of blame goes directly to the HVAC contractor. Poorly-designed and installed HVAC duct systems can account for more than a 60% reduction in total system efficiency, occupant comfort and energy usage. While numerous approaches to duct design have been presented in textbooks and manuals, our unique design method has resulted in thousands of comfortable, quiet buildings with low energy bills.
A Typical radial “spider flex” duct installation:
Even experienced HVAC contractors can run into problems by attempting to design their own systems for tight foam insulated structures. This HVAC contractor ignored our engineered layout and relied on his “30 years of experience” to design this job. These poorly designed systems are clearly insufficient for optimal performance, energy efficiency, consistent air flow and humidity control. In this case, poor performance resulted in a total system replacement at considerable expense and inconvenience.