How important is house tightness in doing a good job in ventilating under wintertime conditions?
Nearly all of the environmentally controlled poultry houses in the United States operate under the principle of negative pressure ventilation. This means that a slight suction or vacuum is placed on the house by the ventilating fans. Thus air is sucked into the house through any available openings because it is flowing from a slightly higher pressure area (outside) to a slightly lower pressure area (inside) the poultry house. This makes it possible to have air enter the perimeter of the house through carefully designed inlets that are an essential part of the ventilation system. But this works only if the house is otherwise tight, with few or no air leaks or “unplanned inlets.” One of the key conditions that must be met to successfully operate a negative pressure ventilation house is that the house must be tight. In the last three years in the United States there has been a great push on to tighten up houses. Houses that have lots of air leaks through the curtains, doors, pad rooms, or
