"How many exhaust fans do I need for wintertime ventilation?" is a question that many broiler producers ask when constructing a new house or remodeling an older one. There is a quick and easy answer. As a general rule, a broiler house should have 15,000 ft3/min of fan capacity (one and a half 36" fans) for every 100' of house length. Therefore, a 400' house would require the equivalent of six 36" fans and a 500' house about eight. Soon after having that question answered, most growers have a sec...ond question, "Why?" This question takes a little more than a sentence or two to answer.