Review: Thermacell Mosquito Repellent Devices


I’ve been lucky enough to spend the past 23 years writing about the outdoors. Along the way, I’ve had the chance to review untold numbers of products that were supposed to make the excursions of hunters, anglers, campers and hikers more pleasant and/or more successful.

Of course, there have been many duds along the way – gear items that simply failed to live up to the promises of manufacturer print ads and TV commercials. And then there are those few truly unique products that not only perform as advertised, but they’re so good they invent and define a whole new category.

Such is the case with Thermacell.

MR-GJ Olive Isolated

I remember the first time I witnessed one used in the field. About 12 years ago I was hunting in south Florida for Osceola gobblers, and my 20-something guide pulled a Thermacell from his turkey vest and fired it up. In all honesty, my opinion of the guide dropped a fair amount.

How can he believe in such a gadget? I thought to myself. And even though the mosquitoes didn’t bother us that morning, I simply assumed the bugs weren’t that bad in the area. But during our drive back to the ranch for lunch, I picked his brain, and he stated in a matter-of-fact tone, “Trust me, Dave. Thermacells work. And I’ll prove it to you tomorrow morning.”

And he did. The next morning, as we waited near a swamp in the predawn darkness for gobbling to begin, my guide and I were getting killed by mosquitoes. I didn’t have a full head net or bug spray, and the bugs were so thick I had to keep my mouth closed to avoid breathing them in. “Ready for some magic?” my guide said as he reached into his vest. “It’ll take 5-10 minutes, so be patient, but I think you’ll be impressed.”

As God as my witness, the Thermacell slowly began repelling mosquitoes. After 5 minutes, the number of bugs on or around me was cut in half. After 10 minutes, they were gone. Gone!

Ever since that day, I’ve relied on Thermacell Mosquito Repellent to make miserable times in the outdoors more enjoyable. I’ve carried them on spring and fall black bear hunts, early season archery hunts for whitetails, and of course, spring turkey hunts. My family brings them to outdoor sporting events during spring, summer and early fall, and it never fails that someone else on the bleachers asks, “Do those things really work?” And my answer is always the same: “Like magic.”


Thermacell for Dummies

Does a Thermacell kill mosquitoes? No. It repels them.

I’ve sat in pop-up ground blinds loaded with mosquitoes, and after firing up a Thermacell, you can watch the bugs fly out every opened shooting window. And after about 10 minutes, you can watch bugs on the outside of the blind make their move to come inside, but after flying in about 6 inches, they quickly do a 180 and exit. It’s actually kind of fun to watch.

So how does the device work? A Thermacell is powered by a small butane cartridge. Butane provides the portable heat that activates the device. The heat generated by the butane cartridge is directed to a metal grill, and a small blue-colored mat saturated with repellent is inserted on top of the metal grill. Heat disperses the repellent from the mat into the air, creating the zone of protection. And that’s why it takes several minutes to realize the total benefit of a Thermacell. Depending on wind, in my experience it creates a bug-free area of at least 10 feet by 10 feet, and under perfect conditions (read, no wind) about 15 feet by 15 feet.

The repellent, allethrin, is a synthetic copy of a natural repellent found in chrysanthemum plants. When the lighting is just right, like in a pop-up blind with some side light coming in window, you can see the allethrin vapor rising up from the device like smoke from a candle.

The view from the author's black bear stand. See the Thermacell sitting on the platform?
A view from the author’s black bear stand. The Thermacell kept the mosquitoes away, allowing him to concentrate on bruins not bugs.

Is it odorless? I can only say that I can’t smell it, and I’ve never had an animal, including whitetails at very close range, ever react to a Thermacell. As for noise, you can barely hear the device running if you put it up to your ear. And when you set the device down beside you, or place it on the base of your treestand, the faint operating noise is totally drowned out by every other woodland noise.

Each appliance comes with one butane cartridge and three repellent mats. Each repellent mat provides up to 4 hours of protection and each butane cartridge provides up to 12 hours of operation. Of course, you can purchase more butane cartridges and 4-hour mats, and new for 2016 are the Max Life Refill mats, which last up to 12 hours.


Here in Minnesota, thanks to an unusually wet August, the number of mosquitoes is higher than I can ever remember. Archery deer season opener is just around the corner, and you can bet I’ll have my Thermacell packed for every morning and afternoon sit, regardless of whether I’m bowhunting from the ground or a treestand.

During warm weather hunts when bugs can be a problem, the author always packs a Thermacell.
During warm weather hunts when bugs can be a problem, the author always packs a Thermacell.

If it’s windy enough that bugs aren’t a problem, I don’t fire up a Thermacell. But at the first sign of trouble – and I’m anticipating several weeks of bug-crazy conditions this September and October – a Thermacell will save my hunts. Let it save your hunts, too.

P.S. The video below provides a quick overview of how a Thermacell mosquito repellent device works.

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