Installing one or more turbine ventilators on a rooftop is an effective, yet, surprisingly inexpensive solution to ventilating an attic or crawl space. Depending on the diameter of the vent and the wind speed outdoors, a turbine vent can expel surprising quantities of hot, humid air.
A relatively small Ventilator, such as a 12-inch diameter turbine vent, exposed to a constant wind speed of 5 miles per hour (mph), for example, can move 347 cubic feet of air per minute (cfm) from a space. A single 14 inch diameter turbine vent exposed to a constant wind speed of 15 mph winds can expel up to 1,342 cfm of air. Even when the winds are still, these vents allow warm air to move up and out of the attic through a turbine vent. As air is pulled out of the attic through a turbine vent, the air pressure in the attic becomes lower it will try to pull outside air into the attic space through soffit vents attempting to restore pressure balance between the outside and inside air.
If the air pressure isn’t equalized, a vacuum may be created. Since it can’t pull air in from outside to restore the equilibrium, the vacuum may pull warm or cool air from the inside of the house: causing energy loss, which makes it more expensive to heat or cool the house. The process described above is one of the major reasons many of today’s municipal building codes require new houses to be built with soffit vents: to relieve the pressure that may cause a vacuum and pull cooler or warmer air from the inside of your home, wasting energy while raising your heating and cooling bills. Or, to put it another way, when your turbine and soffit vents are working correctly and in unison, you can save money and be more comfortable at the same time.