I built a cabinet incubator out of 3/4" plywood. The outside dimensions are 16" W x 16" L x 36" H. I have the heat element used in the GQF sportsman incubators with this fan I bought from Amazon. I'm using this thermostat , also purchased through Amazon. I have the fan at the top with the heat element in front of it (fan is blowing from behind the heat element). I'm getting 15 degree variances between the top and bottom shelfs. I put another small desk fan in there to see if that would help but so far it's not made a difference. Any ideas what else I can do to regulate the heat?