Thank you! here i'm hoping that I can just buy a rack and be done with it. I find that maintaining ambiant temperature around 75f shouldn't be a problem however that goes out the door when my doors to my room is open for more than 2 mins. ambient temperature drop a few degree, same in the tub however it take quite a while for the rack to warm up again. it take about 15 mins for the ambient to go back up to 75f but close to an hr for the rack to heat up again to 90f hotside and around 80f cold side. Because I didn't build the rack myself I'm worry that insulating it would make the tub hard to slide in and out. Where does one find the blue foam insulating material and the reflective material? Do you have a picture of your setup I can take a look at?