Actually I would recommend two PC fans for a 1/2 sq m cab/tent. One on each end. I only put one on one end. That alone was a pain in the ass so I only did one each. These weren't designed as grow tents, but as clothes storage units. I had to do everything myself to convert it. Like I said, there's still a little smell but nothing too serious. Besides, I only have two 12v power supplies. I had 3 but I burnt one out from a short. If it ever happens to anyone you'll know by the smell that it's heating up. I took too long to figure out what is was. I thought it was my air purifier. Good thing I still had 2 left. They all came from PC peripherals that are outdated and never used anymore. Some peripherals have 16v and some have 12v. The 16v ones make them run too noisy.