Chick, I sprayed the INSIDE of my house, around the windows. Window sills, frames, all around. I figured that's where they were coming in at. They were all on the north side of the house, interestingly. And the cool thing is, this lemon oil smells good and is non-toxic. About a month later I took Windex and cleaned my windows real good as they were, well ... oily, lol. But we've never had a problem since then.