And when you get around to installing the fan(s) be sure to set them so they blow at the floor of the cabinet and not the leaves. The leaves can handle the heat but roots can not plus you get the added value of less aroma created by keeping the plants from moving as little as possible. Leaf movement is what creates a good share of the smell that escapes from a grow and if the fans are aimed at the pots there is far less smell to worry about.