Temperature comparisons between the
Three Chamber Bat Box and Seven Chamber Bat Box

This past summer an experiment was conducted to compare the thermal heating of two different size bat boxes.

The two boxes are identical to Bat Conservation and Management's highly successful Seven Chamber Box and the new lightweight Three Chamber Box. We were concerned that the overall lower volume and reduced roof area would prevent the Small Box from achieving proper temperatures bats insist upon. Four remote data-loggers we placed in each bat box to record temperatures 24-hours a day for several summer days.

Inside the Seven Chamber Box
(2' wide, 3' tall, 9.5'' deep):
A sensor was placed at the inside top of the box.
A second sensor was placed fifteen inches below the top of the box.
A third sensor was placed twenty-four inches below top of the box.
An additional probe recorded the ambient temperature as a control.

Inside the Three Chamber Box
(1' 7'' wide, 2' tall, 4'' deep):
A sensor was placed at the inside top of the box.
A second sensor was placed nine inches below the top of the box.
A third sensor was placed fifteen inches below top of the box.
An additional probe recorded the ambient temperature as a control.

Each box had sealed seams, black roofs, and black sides.

By studying the graphs, we were able to conclude the following:

• The larger roof of the Seven Chamber Box absorbs more solar energy than the Three Chamber Box.
• Internal temperature differences between the boxes are less than five degrees.
• The larger volume of the Seven Chamber Box causes it to respond to outside temperature changes slightly slower than the Three Chamber Box.
• The Seven Chamber Box retains slightly more heat into the early morning hours, maximum of three degrees.

We at BCM consider the temperature differences between the to designs to be negligible and within our tolerances.

Temperature data is courtesy of the Pennsylvania Game Commission.

Note: the temperature graphs on the following pages are currently being redrawn to speed download time and present clearer data. Temporary copies exist at this time. Click here to view comparison graphs.