I live in Hawaii on the big island and have these installed at each corner of my house under the eaves. They are controlled by a timer inside the house. However they could be hooked up using  a day/night light sensor and turn on only at night. They say not to install them close to the house, however, since we have a lot of bugs trying to get into the house trying to get to the bright lights, these do kill most of the bugs before they get inside..