Nowadays (industrial) rooms are often very well insulated and less heating capacity is neccessary to reach the desired temperature. However, in these circumstances it is very important that the (warmed up) air is well recirculated by additional destratification fans. At the same time energy is saved because the assembled, useless warm air underneath the roof is returned to working level (= reduction of the temperature gradient).  Therefore, installation of a destratification fan earns itself back quickly because of the realised energy savings.