By far the most effective method of reducing the cost of heating a curtain-sided house is to convert it to a totally enclosed house. Side wall curtains have a very low insulation R-value, approximately 1.5 Fo*ft2 /Btu’s/hr, and as a result are typically responsible for more than 25% of the heat loss from a poultry house during cold weather. Furthermore, side wall curtains are the number one source of air leakage in curtain-sided houses further contributing to a house’s heat loss. When a curt...ain-sided house is converted to a totally-enclosed house the increased level of side wall insulation and house tightness typically results in a fuel savings of between 30 and 50%. Bird performance also tends to increase when a curtain-sided house is enclosed due to the fact that house temperature and air quality are easier to control.