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Varies somewhat by species. Some on the order of hundreds of yards, some much less. Having a bat house near a clearing, or even better near an open body of water (stream, pond, etc) will help attract bats. Be sure your bat house has a variety of roosting slit thicknesses; this will increase the odds of your bat house being occupied by the bats in your area. Some people have reported success mounting the bat house on their house. Most instructions tell you to mount the bat house on the south side of the structure (wall, tree, etc) and make sure it's in the sun for all or part of the day (more sun further north you are located). Female bats (and young) prefer very warm conditions for roosting.
My bat house (homemade) was not occupied in its first year. Second and subsequent years there have been a few occupants. By all means, please try to install a bat house; encourage your neighbors to do the same. Place it between 10 and 20 feet above the ground, with a clear, unobstructed opening underneath. Bat populations are on a decline in the USA, and whatever we can do to forestall thus decline will help in keeping check on the mosquito and other flying pest populations far better than chemical means. They are marvelous, interesting creatures as worthy as our feathered friends who receive much more attention.