Gear Review: Thermacell Backpacker Mosquito Repellent

I hate mosquitos. A big part of why I rarely backpack close to my Ohio home in the summer is because I don’t want to deal with them. The choice of getting repeatedly bitten or covering myself in Deet on a hot summer evening is picking one of two bad options to me. So you know, I’ve tried other chemical sprays and lotions, but for me, nothing works like Deet.

I’d looked at some of the Thermacell products in the past, but they all appeared to be too heavy and/or bulky to bring backpacking. I was intrigued however when I saw that Thermacell had created a mosquito repellent device targeting backpackers.

All Thermacell devices work on the same principal. They use a fuel source to heat a mat impregnated with a chemical called allethrin. The chemical is in the same class as Permethrin, which is used in insect repellent clothing. Both are synthetic versions of pyrethrum, a naturally occurring chemical found in certain types of the chrysanthemum plant. The device heats the chemical causing it to vaporize into the air where it does not kill the mosquitos, but repel them.

The EPA Material Safety Data Sheet cautions against eating it or putting into water (toxic to fish). However, the personal protection requirements are to use with proper ventilation (outside only). No protection is needed or recommended for skin, eye or respiratory exposure. The sheet for Deet looks scarier to me.

Anyhow, at only four ounces, the Backpacker version of the repellent device seemed to be worth a try. The repellent promised a 15′ by 15′ zone of protection by using the isobutane fuel canister that I already carried to power my small stove. The initial package was $39.99 and also contained three of the chemical mats; enough for 12 hours of protection.

The product appears to be well constructed and simple to use. Screw onto a gas canister, slide a mat under the guard, turn it on and push on the starter. A small viewing port lets you check that it’s lit. Gas usage is minimal. Thermacell states that a four ounce canister will power the repellent for 90 hours.

My first use was at a family picnic. I fired it up on my deck as the sun set and we spent the next hour or so mosquito free. No noise, no mess and no significant odor. When everyone came inside I just switched it off.

The real test was a recent backpacking trip. The skeeters were bad enough through the day’s hike that some Deet was required. Once we set up camp and had dinner, it was just getting dark. At that point I was expecting an onslaught. Done with the stove, I hooked up the device to my gas canister and started it up. I was still using the original chemical mat. They change color as they’re used up so I could easily tell it was still good. The onslaught never came.

I was thinking that perhaps the Deet from hours earlier was still working, but a quick stroll away from the Thermacell proved otherwise. The mosquitos were still in the area and eager to draw my blood; just not within range of the device. I did not bring a tape measure to gauge the exact size of the zone of mosquito protection, but it seemed like the advertised 15′ by 15′ area was a good estimate or even conservative.

With the included carry bag, the device weighs 4 1/2 ounces

Would I take this device on a thru-hike? No; just like I wouldn’t bring a camp chair. If I’m trying to cover long miles, the extra weight and time needed for these conveniences aren’t worth it to me. However, a weekend trip is a different story. This could make a summer evening spent hanging out at the campsite much more enjoyable than slathering on the Deet or being driven into the tent early.