The ventilation of a Roanoke Barn forces air through the leaf. So long as the humidity is on-program, that air is recirculated. When the program needs to lower the humidity, a valve opens in the ducting to variably vent the circulated air to the outside.
[By the way, I've seen used Roanoke Barns for sale for about $1200. That was several years ago.]
Bob
[By the way, I've seen used Roanoke Barns for sale for about $1200. That was several years ago.]
Bob