I am a new herper facing my first winter as a rack owner. I have purchased a Nature's Spirit 15qt & 32qt rack and I am using a Ranco thermostat to control it. I was unhappy by the fact that I would have to set the thermostat at 20 degrees higher than the temperatures actually achieved. Reading postings on different forums I see that this is a common situation. I also see that it is assumed by the rack makers that the average temperature of the room will be 74 degrees or so. In my house we never set the thermostat any higher than 68 degrees, and quite often even lower. Casey Hulse the owner of Nature's Spirit Reptiles and the person that built my rack had told me at the time that I purchased it that the outside back wall of the rack could be insulated to help get the temps up if need be. I decided that Reflectivex insulation would be the best way to do it but I didnt like the cost of it. I noticed that panels made to cover the windshield of car and reflect the sun to keep a parked car cool in the summer were made of the same material and are commonly sold at Dollar stores and at Big Lots for about $2. I covered 2 sides of a piece of cardboard cut to size and neatly taped the edge with aluminum tape.With this on the back wall the temp in the tubs went up 3 degrees.I had taped the probe directly to the flexwatt. I took the temp of the flexwatt and found that it wasnt as hot as the Ranco was set at. I remembered seeing a post by Larry Suttles that he makes sure not to cover the probe with the tape. I re did this with the probe still directly on the flexwatt but not covered by tape and found that this allowed me to run the Ranco at another 4 degrees lower to achieve the same temp. So all together by making these adjustments I can set the thermostat 7 degrees lower than I was before. I thought that I would share this in case any other newbies were having a problem with this as I did.