ACHRNEWS

Skaer-Tactics: Underfloor Air Distribution Systems: Good or Bad?

April 22, 2008

I was recently invited to take a tour of the headquarters of a firm in St. Louis that provides solutions for mission critical facilities throughout the United States. Rather than spill all of the beans here, my visit will be featured in an upcoming issue of The NEWS. This firm was proud of its new office surroundings, which was originally built in 1967 and was a printing press and warehouse. Among other things, company officials touted its underfloor air distribution system.

In the eyes of these folks, such system in the design of new construction and renovation projects can contribute significantly to the LEED points earned on a project and greatly enhance the overall owner/occupant experience - but only if it is designed and constructed correctly, they stressed.

Apparently, not all underfloor systems are put together correctly. Surprise! The same can be said of any HVAC system, right?

After seeing this building, it makes sense to me that, at the very least, more office buildings should incorporate this type of system. It takes advantage of air’s natural tendency to rise as it warms. Air distributed from the floor is introduced at a lower velocity and, according to these folks, requires less heating/cooling than air from overhead systems, which usually reduces energy consumption and operating units. Such a system is normally lower in cost to install, as there is no overhead ductwork but only very little underfloor ductwork. Distribution components - diffusers, underfloor volume air volume units - can be easily reconfigured and reused, reducing costs associated with moving people around in an office. Incoming fresh air is not mixed with the warm, spent air at the ceiling, so occupants can get first benefit of the air. For employees, this means they can adjust diffusers in their work areas for individual comfort.

In truth, I’ve never heard anything bad about underfloor air distribution systems. For office building owners, it makes total sense to have such a system as it is far easier to reconfigure an office space floor to meet occupant demand than it is to reconfigure ductwork above or tearing down walls to make sure the heating/cooling needs of occupants are met.

If you have tried and installed an underfloor air distribution system, let me know how it went. Of course, let me know your opinion regarding the system. If you have never installed or speced such a system, why not? What are your fears, if any?

I’d like to start a dialogue on this subject. With input, this could generate another feature in The NEWS, detailing the pros and cons of air distribution systems.