i would love to do radiant heating, and that is actually going in my addition i am building for my paint booth, but as of right now, i am working with an already poured foundation. as for the infrared heating, i guess what i was trying to say is, how many btu's would be the minimum for an 18 x 26 ft booth? i have found a couple of 60" single bulb infrared heaters that put out 13500btu's a p[iece, but they are 230vac lights....and i would need about 8 of them from my calculations to get the desired heating i think i need.