Controllability of Systems

Are you relying on thermostats as the only user controls or in combination with other controls such as diffusers or operable windows? The temperature range might be okay, but thermostats alone may not meet the requirements.

We've only seen this credit achieved in commercial buildings with underfloor air systems that provide control of individual diffusers in the office areas, or small projects with many operable windows. We've understood the credit as having to provide 50% or more of the occupants with individual controls for *each* person. Thus, for 100 people you would need 50 controls, each of which can be individually adjusted.

With a UFAD system, this has been achieved when the number of adjustable floor diffusers in the office areas is equal to or more than 50% of the number of occupants in those areas. With operable windows, we've seen a small, open office along a perimeter with 10 occupants and more than 5 operable windows along the length of the space.

It is also possible to pursue this credit with a VAV system if you provide a large number of VAV boxes and add controllable ceiling grills (such as "thermafusers") so that the number of VAVs plus controllable grills is equal to half the number of occupants. This is not a common approach, but we have tried it with small projects that have a lot of meeting rooms and not many offices.

You could do this (thermafuser) also in an open office I would say.