How important is "lock down", if the ambient humidity, in the room my incubator is in, stay's around

[BrannonGale]

Thank you for the encouragement. I have a little Giant still air incubator w/ egg turner. I am building a cabinet style incubator, with three separate 42 egg incubation chambers. Two chambers for turning, and one chamber for hatching. Each chamber will be individually controlled with separate thermostats. Has anyone used: http://incubatorwarehouse.com/48-watt-incukit-dc.html ?