help with heater

well i said this somewhere before but doing a grow in out building with no kind of heat the lights are floros so they dont heat enough 4 4' 54w/ho 865 halide so i was wanting to know if anyones run across this situiation and what would be a good heat sorce?a space heater with themastat?trying to keep power bill as low as possiable or should i just wait till first of year when it dosent get as cold at night?

an electric space heater can get pretty expensive, unless you can make your grow area as small as possible (no unused room), and insulate the heck out of it ... also, the 'radiator-type' oil-filled heaters are the cheapest to run, that I've tried ... usually about $50 at WallyWorld ... :smokin: