Better Air recommends a negative pressure system for evenly controlled, draft free, year round ventilation
Negative Pressure System
Exhaust fans create negative pressure, removing moist contaminated air Fresh air is pulled in through core fully positioned and controlled inlets, mixed recirculated and if necessary heated for precise moisture and temperature control. A consistent and comfortable environment supporting healthy and productive animals.
All livestock housing requires ventilation. A well ventilated barn provides a comfortable and healthy environment, affecting the animals' productivity and the operator's well-being. Despite the importance of ventilation, the design of a ventilation system and selection of ventilation equipment are often given the lowest priority in barn construction. Every animal continuously produces heat, moisture, and carbon dioxide; some also shed micro-organisms and minute skin particles. Out of doors these contaminants quickly dissipate into the atmosphere; in a barn, however, they accumulate unless removed. Feed dust and manure gases further aggravate the problem.
Ventilation moves clean air though the barn airspace to dilute and remove the contaminates and replenish oxygen levels. There are two basic types of ventilation, natural and mechanical. In natural ventilation, air movement depends entirely on outside wind and temperature gradients. This has proved ineffective in some barns, where failure to remove excessive moisture has resulted in structural deterioration. In mechanical systems, fans control the air flow. Mechanical ventilation employs either positive or negative pressure. In positive pressure systems, fans blow fresh air into the barn creating positive internal pressure that forces an equivalent amount of stale air out of the building. This system is effective in summer months when the direct air movement has a cooling effect on livestock.