I have a mini split 12,000 BTU in my 400 Sq foot garage in Las Vegas. We have temps from 40s in the winter to 115 in the summer, luckily no humidity. The mini split cost me $ 750 ish and $ 400 to install after getting quotes upwards of 2500-4000. It does a great job keeping the temps where they should be, just not when i open the door