Thermal destratification

Destratification is the reverse of the natural process of thermal stratification, which is the layering of differing (typically increasing) air temperatures from floor to ceiling.

Other variables that influence the level of thermal stratification include heat generated by people and processes present in the building, insulation of the space from outside weather conditions, solar gain, specification of the HVAC system, location of supply and return ducts, and vertical air movement inside the space, usually supplied by destratification fans.

[citation needed] In a study conducted by the Building Scientific Research Information Association, the wasted energy due to stratification increased consistently based on temperature differential from floor to ceiling (ΔT).

Since ΔT tends to be higher in taller ceilings, the effect of stratification is compounded, causing substantial energy waste in high-ceiling buildings.

Because axial fans are designed to blow air straight down at the floor, they can be used in ceiling and roof structures over 100 ft. tall.

When used in the summer to encourage evaporative cooling, HVLS fans are run forward, blowing air at the floor.

As a result, destratification technology has great potential for carbon emission reductions due to the reduced energy requirement, and is in turn capable of cutting costs for businesses, sometimes by up to 50%.