I thought about it Tim. I don't want to buy the insulation for it now. There was a bunch of rigid insulation in the rafters there. I spread that around to make a "ceiling". I think a sunflower will heat it ok as long as it's not too cold outside.
I have been in fish houses with a lot less...

When I have the means, I'll probably pick up a few rolls of insulation, but it probably won't be before this winter.