ThermaCELL provides protection from mosquitoes within 15 feet of the device. If you want to keep a larger area mosquito-free, use more ThermaCELL devices. A ThermaCELL device uses the energy from a butane cartridge to heat up a mat saturated with allethrin, which is a natural insecticide derived from chrysanthemum flowers. The heat releases allethrin vapors into the air, keeping mosquitoes away. Because it doesn't need to be plugged into a wall socket for energy, you can carry a ThermaCELL device anywhere.

Step 1

Turn the device off. Insert a new ThermaCELL mat under the black grill. A new mat has a pale blue color and turns white after four hours of use when it no longer contains any active ingredient.

Step 2

Take off the ThermaCELL device cover, located at the part of the device that is furthest away from the black grill. You will see a socket for the butane cartridge.

Step 3

Remove the cap of a new butane cartridge and insert the cartridge into the socket. Turn the cartridge clockwise to keep it in place. One cartridge runs for eight to 12 hours.

Step 4

Place the ThermaCELL device cover back on and turn on the device by sliding the switch located below the black grill. Wait for five to 10 seconds and press the "Start" button quickly three to five times. The "Start" button is located below the black grill, beside the on/off switch.

Step 5

Look at the top of the ThermaCELL device. A light glows if the device is heating. If the light is not glowing, turn on the power switch and insert a cartridge if necessary, and then press the "Start" button three to five times again.

Step 6

Place the ThermaCELL device on a flat surface with the grill facing up. It takes between 10 to 30 minutes to start repelling mosquitoes.