We live next to a few hundred acres of hills. When summer evenings arrives every day, all the bugs on the hills gather around the light source and take over the patio. They are not necessarily mosqitoes but some of them sting anyways. The fist unit we bought at Costco were not a flowtron. It worked... some... Then we tried Flowtron and have not looked back since. We hook Flowtron up to a outdoor dust to dawn timer and keep it on for 2-4 hours depending on the temperature. When temperature cools down, we are not bother by bugs and neither should the Flowtron. On warm nights, the first 1-2 hour when Flowtron comes on, it's non-stop actions. Although it's hung at the outskirt of our patio, we generally avoid the outdoors during that one hour. Once the zapping dies down in a hour or two, it's safe for us to go out.