The greenhouse we designed and constructed is about 11' x 15' with an 8 1/2' roof at the peak. We mounted the fan at one end of the long end, the doorway is at the other end. We live in Texas, so the heat is more of a problem during the summer for any greenhouse here, but they are great in the winter. The installation went well, and with a shade cover over the greenhouse and the fan we are able to keep the greenhouse temps down 10-15 degrees lower during hot weather than the ambient temperature. We also have a mister that provides a bit of humidity which also helps when the temps get up in the high 90's and 100's. The vegetables we are growing in there this Spring are doing great!