It's been years since I've been on this forum. About 10 years ago I installed a Solo Plus boiler which operates smoothly. I use a combination of old cast iron radiators and cheap baseboard. Attached to the house is a small 9 X 13 greenhouse, which I'd like to heat. I installed the whole of the current system. How would I go about putting in an in-slab radiant loop for the greenhouse, or am I better off to just find cast iron radiators for the space and treat it like a seperate zone? As I understand it, the trouble with the radiant is that they operate at very low temperatures. Any advice would be appreciated.