Hot air rises so in a typical house the upper floor is much warmer than the lower floor, often to the point of being at the same time uncomfortably cold downstairs and too warm upstairs. We use an anti-stratification blower (a Blue Ridge Energy Systems innovation we call ASB) that simply moves warm air from the top of the house to the lower floor to reduce this effect.
This unit is inexpensive to install and run, quiet, and highly effective. It is one of the many well thought out features that make BRES houses so easy and comfortable to live in. Generally the temperature differential throughout the entire house will not be more than 3 degrees, compared to 10 or 15 without this air movement.