What is Bat Conservation International's (BCI)
Many bat houses on the market today are not suitable
for North American species because of poor design or
construction, and many also lack proper instructions
concerning painting, placement, sun exposure, and
mounting. In response, BCI has established a
Bat Approved Certification Program to help improve
the quality of commercially produced bat houses. In
addition to the bat houses BCI offers in our catalog,
there are now designs from other companies that meet our
BCI's Bat Approved certification will demonstrate to
prospective buyers that a bat house is acceptable to
bats. Manufacturers can use the Bat Approved logo on bat
houses, and in the instructions, packaging, and
advertising (for approved bat house designs only).
Advertising for approved designs must be reviewed by BCI
for accurate content. BCI will provide a letter of
certification for manufacturers that can be copied and
included with approved models.
We hope this Bat Approved program will encourage
manufacturers to design bat-friendly, high-quality bat
houses. Those houses which successfully attract bats
will further conservation efforts as well as strengthen
manufacturers sales. As a result, everyone benefits.
As interest in bats continues to grow, so has the
number of bat houses on the market. However, many bat
houses are designed and/or constructed such that they
are unlikely to be used by bats. Most follow outdated
designs which are too small to meet the needs of bats.
In addition, instructions for proper installation and
treatment are often inadequate. In response, Bat
Conservation International created the Bat House
Certification Program in 1998 to help manufacturers
build high-quality houses that bats will accept.
BCI and numerous volunteer Research Associates in the
Bat House Project have conducted years of research to
determine which criteria contribute to success. Results
show that tall and wide designs offer greater
temperature diversity, a key factor in attracting bats.
Proper crevice dimensions, roughened interior and
landing areas, ventilation slots, and tight, draft-free
construction are also extremely important. Because
accurate instructions are just as important as having a
good design, it is vital that information be enclosed
with each bat house sold concerning correct placement,
sun exposure, painting, habitat, and other variables.
Manufacturers who wish to earn the Bat Approved
certification must submit a finished bat house to BCI
for evaluation. Bat houses will be reviewed according to
the guidelines below. Only those houses that meet all 10
criteria will be certified. Manufacturers will be
provided with a copy of the evaluation and comments.
After a manufacturer submits a model for review, its
design, construction, overall quality, instructions, and
literature are evaluated. Only those models meeting all
of our guidelines will earn certification.
BCI Approved Guidelines for Bat House Design and
1) Roost chambers must be a minimum of 20 inches
2) The width (side to side) of roost chambers must be
at least 14"
3) Roost partitions must be spaced 3/4 to 1 inch
apart (front to back). The best crevice size for most
North American bats is 3/4 inch.
4) Bat houses must possess a suitable landing area.
Either a 3- to 6-inch landing area must extend below the
5) Interior surfaces and landing areas must have
adequate texture to provide footholds for bats. such as
rough cut wood.
6) Screws, staples, nails, mounting hardware, or
other sharp objects (including splinters) must not
protrude into roost chambers.
7) Half-inch tall ventilation slots must be provided
and be placed no more than 1/3 (one-third) the distance
from the bottom. Front vents must be as long as a house
8) Boards should come from quality stock such as
cedar or pine. Any plywood used must be exterior grade
(e.g. ACX, T1-11, BCX). Pressure or
chemically-treated wood must not be used, as they
contain substances which may be harmful to bats.
9) Overall construction must reflect that the bat
house is a quality product. Bat houses must be durable
and tightly constructed (no unplanned gaps). Caulking or
gluing exterior joints is required to prevent drafts.
Bat houses must be durable and long-lasting, as they may
not be occupied for two years or more.
10) Advertising and any instructions or literature
included with bat houses must be approved by BCI.
Unsubstantiated or misleading claims (e.g. no more
mosquito problems) will not be permitted. Instruction
sheets included with bat houses must contain adequate
information on painting, sun exposure, mounting height,
mounting sites, and recommended distances to water and