FANSTjernlund Products says its Duct Booster Fans help boost air flow to areas that are hard to heat or cool. The fans can also exhaust foul air from a bathroom or pole barn. The family of Duct Booster fans designed for installation within heating and cooling ducts to increase the flow of conditioned air to desired areas. There are models of varying capacities for installation in metal and flex ductwork. Optional accessories are available for automatic activation and to control fan speed.

Tjernlund Products Inc., 1601 Ninth St., White Bear Lake, MN 55110-6794; (800) 255-4208; fax (651) 426-9547;