Up to 90% of the heat lost from heated livestock buildings is lost in the ventilation exhaust air. There has recently been a great deal of interest in the recovery and reuse of this energy with heat exchangers designed specifically for livestock building applications. Heat exchangers provide several advantages to the livestock producer, however the heat recovered is not necessarily “free”. The purpose of this paper is to evaluate the use of heat exchangers on the farm and to help the livestock producer decide if he would benefit from and could justify one on his or her farm.