Negative Pressure Ventilation - Inlet machines
The number, as well as size, of air inlets recommended for negative pressure houses has steadily increased over the years. Ten years ago, a 400' house may have had only ten or twenty 4" X 4' inlets (13 ft2), if any at all. Today, many new houses have over fifty 7" X 4' inlets (140 ft2). The dramatic increase in inlet area has given producers a higher level of control over house temperature, air quality, and fuel usage. The more control a grower has over these factors, the more control he has over his paycheck.