Will a box fan in our attic help?

We just placed a box fan against our side vent in our attic. It is pointing outwards pulling air from the attic and blowing out. We have the rest of the vent blocked off with cardboard so it has to go through the fan. The box fan says it has a plug that has a fuse in it for shut off ... will this help coolour house... we are renting the house so not wanting to spend lots of money on a house we are just renting.