The report describes the construction of a heat exchanger using relatively inexpensive and corrosion resistant materials. Computer simulation of the heat exchanger performance in a typical pig finishing house is also described. Laboratory experiments on the heat exchangers’ performance indicated an effectiveness in the order of 40%. The computer simulation uses this value, hourly weather data for one year and typical data for a finishing house for its calculations. The simulation calculates the reduction in additional feed costs due to house temperatures below the critical, when a heat exchanger system is incorporated. The paper shows how the value taken for minimum ventilation rate determines the economic viability and need for heat recovery.