I have a 10x12 wooden shed thats sturdy that I've wanted to turn into a grow room for years. Problem : No heat/winter no A/C/summer. Would a portable heater/fan solve it?
That all depends on if you can keep your temps at reasonable levels. You would also need a considerable amount of insulation.
I'm heating a 10x11 with a 1000 watt oil raditor heater. The walls are insulated and I'm running T5's and the temp will drop to 68 on cold nights. Cold meaning 34 degrees. I think you would really need to insulate and seal the room and run some 1000 watt lights. Don't forget to run CO2 which will add additional heat and give you the proper goods for a sealed room. Might want to budget for sulfur burner and dehumidifier you will need them. Remember your girls will slow way down at temps below 72 degrees. I hope this helps.