Bat Houses in Utah

The short version

A bat house will not get bats out of your attic. What it can do is give a colony that has just been excluded from your home somewhere safe to go, so the bats stay nearby, keep eating insects and raise their pups outside your walls instead of looking for a new gap in your house. The U.S. Fish and Wildlife Service calls replacing roosts lost to exclusion or demolition "the best use of bat boxes." Utah State University Extension says alternative roosts can encourage bats to remain in the area and reduce their mortality when they are excluded, and that they should ideally be ready before the bats are excluded.

Timing a bat house around a Utah exclusion

In Utah, the exclusion itself is limited by the calendar. The Utah Division of Wildlife Resources says female bats usually move into buildings in May or June to give birth, advises against sealing openings from May through August while pups can't fly, and names fall as the best time to seal a house. DWR also says Utah's five migratory species leave from late August through October and return in April and May.

That makes the months after a fall exclusion the natural time to put up a bat house. Bat Conservation International (BCI) says houses can be installed any time of year but are more likely to be used during their first summer if they go up before the bats return in spring. When a house is paired with an eviction, BCI advises installing it at least two to six weeks beforehand if possible. In Utah, that typically means one of two schedules:

• Exclusion this fall, bat house this winter. When the colony comes back in spring and finds the attic sealed, the house is already on the wall.
• Bat house in spring, exclusion in late summer or fall. The bats have a full season to discover the house before their roost is closed.

Which Utah bats use bat houses?

The Fish and Wildlife Service says 16 North American species roost in colonies, and that the big brown bat, little brown bat and Yuma myotis are widespread and frequently use bat boxes. All three live in Utah. USU Extension calls the big brown bat the most common bat in the state and says about half of Utah's bat species use buildings. Large summer groups in a bat house are almost always pregnant and nursing females. FWS notes that bat houses generally aren't used in winter and don't provide conditions for hibernation, so an empty box from November through March is normal.

Design: bigger and multi-chambered

• Multiple chambers. FWS recommends multi-chamber maternity boxes with venting. If you install only one, choose a box with four or more chambers that is taller than it is wide. Avoid birdhouse-sized boxes and large single-chamber boxes, which can't hold a good range of temperatures.
• Narrow roost spaces. BCI says the spaces between chambers should not exceed 1 inch, which also keeps raccoons and owls out.
• Rough, untreated wood. BCI recommends natural wood with no chemical finish inside, roughened so bats can grip. Its current guidance says not to staple screening or mesh onto roosting surfaces, because bats, especially pups, can get trapped. (Older BCI plans called for plastic mesh, so check the date on any plan you download.)
• Sealed seams and low vents. Caulking the seams stops drafts, and vents in the lower third of the box give bats a cooler zone on hot days. BCI's older criteria call for vents wherever July highs average 85°F or more, which includes every Wasatch Front city.
• Exterior paint only. Use exterior-grade, water-based paint or stain on the outside, and don't paint the interior.

What color for your part of Utah?

A bat house's shade controls how much sun it absorbs. BCI's long-standing criteria recommend black where average July highs are under 85°F, dark colors such as dark brown or dark gray at 85–95°F, medium colors at 95–100°F, and white or light colors above 100°F, adjusting darker for less sun. BCI's newer guidance adds that avoiding dark shades can matter if even short periods get hot. Utah runs from mountain towns to low desert, so the right answer changes across the state. Here is how NOAA's 1991–2020 July normals line up with that chart:

July highs: NOAA NCEI 1991–2020 monthly normals for the stations named. Shade recommendations: BCI Criteria for Successful Bat Houses; "add afternoon shade" notes reflect BCI's advice to favor morning sun in warm climates.

Most Wasatch Front and Cache Valley homes fall in the "dark" band. Provo is just over 95°F, and Salt Lake City and Kanab are close behind, so on a west- or south-facing wall in those areas a medium shade or afternoon shade is the safer choice. In St. George and Moab, overheating is the bigger risk than cold. FWS says bats bulging out of the bottom of a box, fanning their wings or flying during the day are signs of heat stress, and recommends adding a temporary awning or a second, shadier or lighter box nearby.

Where to mount it

• Height: BCI says there should be at least 12 feet of open space below the entrance so bats can drop and take flight. Its installation guide says 12 to 20 feet is better. If cats roam the neighborhood, go higher.
• On a building or pole, not a tree: BCI ranks a house mounted on a building above one on a pole, and a pole above a tree, where branches block flight and give owls access. Wood, brick or stone walls hold heat well. Houses on metal siding are seldom used. Two boxes back to back on a pole give bats a choice of temperatures.
• Sun: BCI says bats prefer early morning sun and at least 7 hours of sun a day. In hot areas, an east-facing wall or space under the eaves helps prevent overheating. BCI's older criteria say houses where July highs average 80°F or less need at least 10 hours of sun, which applies at Park City's elevation.
• Clearance and light: keep it 20 to 25 feet from tree branches, wires and other perches for predators, and away from porch or security lights.
• Not over doors, windows, patios or the grill: guano will fall below the box.
• Near water: BCI says most nursery colonies roost within ¼ mile of water, preferably a stream, river or lake. DWR notes that Utah's bats rely on standing water for drinking and for insects. Homes near canals, the Jordan River, Utah Lake or the Great Salt Lake wetlands have an advantage.

Safety: rabies, cats and pesticides

A bat house brings bats closer to people and pets, so set a few rules. Never touch a bat. Utah DHHS reports that every animal that tested positive for rabies in Utah in 2025 was a bat, and those 24 rabid bats exposed at least 19 people and 26 pets. Keep dogs and cats vaccinated, and call your local health department if anyone may have had contact with a bat. BCI also warns against putting up a bat house where outdoor cats roam, because cats learn to wait below the exit, and against using pesticides or herbicides in the yard, which reduce the bats' insect prey and end up in their bodies. Don't try to catch bats and put them in the box, and don't use guano or scent lures. BCI says they don't work.

Patience and upkeep

FWS says bat boxes put up for general habitat can take up to five years to be occupied, although bats that have just lost a roost may move into an alternative the following season. BCI cautions that some houses are never used. Once bats move in, they tend to come back year after year, so check the box once a year while it's empty. In Utah that means winter: re-caulk seams, touch up paint and clear out old wasp nests. Never open or disturb a box while bats are inside, and don't buy a flip-top box that invites people to look in.

How this fits with getting bats out of your home

A bat house is an add-on, not a substitute for exclusion. Bats in Utah are protected wildlife, and DWR says an attic colony should be handled by a permitted wildlife nuisance control company, which coordinates the timing with DWR. Utah Wildlife Specialists inspects homes, installs one-way exclusion devices in the legal window, seals entry points and cleans up guano. If you want to keep bats in the neighborhood after they're out of your house, we can talk through bat house placement during an inspection.

Related guides: Utah bat maternity season, are bats protected in Utah?, exclusion vs. repellents and bat species in Utah. You can also browse our service area.

Common questions

Sources

1. U.S. Fish and Wildlife Service: How (and whether) to install bat boxes
2. Bat Conservation International: Bat houses (current guidelines and safety principles)
3. Bat Conservation International: Criteria for Successful Bat Houses (PDF, hosted by UC ANR)
4. Bat Conservation International: Installing Your Bat House on a building (PDF)
5. Utah State University Extension: Bats (Wildlife Damage Management Series, PDF)
6. Utah DWR: What to know about bats in Utah (July 14, 2026)
7. Utah DHHS: Rabies Annual Report 2025
8. NOAA NCEI: U.S. Climate Normals 1991–2020, monthly (station July average highs)