you can still put that fan in upside down. it should be blowing up, not down. if it's blowing down, take it off and flip it over..I didn't put a special fan in it. It's an LG so, I just bought and LG fan and installed it. It was made for the LG incubator. I had 4 get sealed in & had to help them out. They are doing wonderful now. Thankfully, I was paying attention.