How long has static regain been used for ductwork design?

January 31, 2012  |   FAQ's   |     |   6,554 Comments

Static regain has been used since the 1940s and followed the development of the commercial fan and air moving market.  Static regain is very friendly to long term operations but it took a lot of calculating, adjusting sizes and recalculating to get a system balanced on paper.

With computer availability in the 1970s, static regain was done with a punch card input system. In the early 1980s, the IBM PCs were used to calculate DOS based programs for VAV systems. With Windows PCs in the 1990s, static regain became much easier.