This fellow has a wing span of about 8 inches which is large, typically these bats have bodies the size of hamsters and wing spans of 5-6 inches.
Feeding must be very good at the moment as the skeeters are out in force as it rained pretty good about 5 days ago.
Try this link to BCI which has a good picture of a similar type. Not sure if the type in the pic is really the same but it looks about right for what we see when they roost under our eves.
http://www.batcon.org/vrcGallery/detImg.asp?img=76583&imgCat=&imgKwd=&srchType=
Microchiroptera
Family: Vespertilionidae
Genus: Nycticeius
Species: humeralis
Common Name: evening bat
Family: Vespertilionidae
Genus: Nycticeius
Species: humeralis
Common Name: evening bat