I try, I do a lot of adapting one thing to something else in my job I saw wood hinges on a box and took that idea and came up with this.
The insulation works well I have used it for years, foam board might not be enough however I use 1/2 inch blue foam usually. I also have a fluorescent light fixture in the enclosure and that helps bump the temps up a lot in the day when it is on. If you have decent insulation it will hold for awhile. I use the insulation only in the winter months.
This enclosure runs dual heating as well hot and cool with a dual probed herpstat to control it. (herpstat 2)