My family and I love nothing more than spending time in the great outdoors. Whether it’s basketball in the driveway or an outdoor movie night in the backyard, we aim to be alfresco whenever possible — that is, until dusk sets in, and the mosquitoes come out in droves. Truly nothing can ruin a lovely summer meal with family and friends on the patio like swatting bugs away from your food and body, all while trying to maintain a conversation.
And while bug repellent sprays certainly provide a barrier of protection, the smell and residue require showering off at the end of the night — something that is not an easy feat when you have four kids. Hence why I was utterly intrigued by the Thermacell E55 Rechargeable Mosquito Repeller, which claims to provide a 20-foot zone of protection that is invisible, scent-free and silent. Read: No hearing “zzz” every time a bug gets zapped!
Half the size of a portable speaker, the Thermacell E55 weighs just 12 ounces and is powered by a rechargeable lithium-ion battery with a 5.5-hour life (unless you run it while charging) that works to heat and diffuse mosquito repellent into the air. More about that repellent: Contained in a liquid solution cartridge, it comprises an active ingredient of metofluthrin (5.5%) and contains petroleum distillate, but has zero DEET or citronella.
Which led me to my first big question — is it safe for adults and children alike to sit amidst this active ingredient for several hours while enjoying the open air? “You will be using this product outdoors so actual exposure will be pretty low,” said Elmer Gray, entomologist at the University of Georgia. “The EPA describes metofluthrin as ‘practically non-toxic’ to humans, so yes, I would say it’s completely safe.” And if you’re wondering about pets, we get it! While metofluthrin can be neurotoxic to pets, Gray assures that the Thermacell is safe to use around your furry friends, when used correctly and according to instructions. “The fact that the [Thermacells] are approved by the EPA pretty much tells you what you need to know,” he says. “The entomological profession sees the EPA as being very restrictive these days, so for them to approve something tells you that when used properly, with a very wide safety margin, it is OK.”
Next up: Can DEET-free products actually, ya know, work? The answer was a resounding “yes” according to the experts I spoke to. “The active ingredient, metofluthrin, is an effective spatial repellent against mosquitoes,” said Dr. Eva Buckner, assistant professor and medical entomology extension specialist at the University of Florida. “[That said], spatial repellent emanators are most effective in situations of little wind, which would allow the repellent to stay in the air around people.”
Added Gray, “A light breeze is going to move the vapors toward the downwind side, making the area of protection more oval than round. I find [Thermacell’s] estimation of a 20-foot-wide area of protection pretty ambitious — I’d still rather be within five or six feet of the device if the mosquito populations were extensive.”
With all that in mind, I tested the Thermacell E55 out in my home’s always-buggy backyard four times over the course of two months, for lengths of time varying between one and three hours and with groups ranging from two to eight people. Here’s what I found.
What we liked about the Thermacell E55
Gone are the days of yore when you used to sit outside amidst the glow of a neon light and constant “zzz” sounds emitted from your family’s enormous bug zapper. Thermacell E55’s modern-day alternative is pretty much the opposite — diminutive in size, the device is also truly silent, delivering an invisible and scent-free vapor into the air. To the point that I said to myself multiple times, “Is this thing working?” (Luckily four tiny lights indicate that it’s on and running.)
I also tested the product inside for about 10 minutes (don’t try this at home, kids!) to see if there truly was no scent or sound emitted, and alas, that claim completely holds up. I was, however, able to see a slight plume of vapor coming out the cover of the repeller, which was easier to capture indoors without any breeze to dissipate it.
In terms of setup, the process is easy breezy, and can be done in seconds, not minutes. Once it’s charged, you simply bring the device to your outdoor spot, insert the liquid cartridge, remove its cap, place the repeller top back on and press the power button. Next you place the E55 in the spot you plan on hanging out in for roughly 15 minutes prior to entering the bug-free zone, which will then be saturated with the repellent. Note: The repeller also takes a few minutes to heat up, indicated by a chasing light pattern around the power button, which becomes static when it’s ready to go.
Ultra-portable — there was one occasion where my group switched outdoor locations and the Thermacell E55 came with us — the device is small enough that it can easily be tucked into a backpack or purse, making it great for traveling (and camping!) too. And aesthetically it’s sleek and small enough to not look like an eyesore in your outdoor space.
I’m also not mad at that $40 price tag. The E55 is cheap enough that I’d consider buying two, either to create one larger overlapping zone or to have two protected spaces in separate areas of my yard. It also comes with a two-year warranty that can be upgraded to three years if you opt to register the product, which brings me a boatload of peace of mind.
The biggest selling point for me, however, was the E55’s efficacy. I have to say it worked incredibly well every single time we used it. While a few of us did hear buzzing (maybe it was phantom buzzing due to mosquito PTSD?!), and there were a few times we had to swat bugs away from exposed food, literally none of us had any resulting bites when we were within roughly 10 to 15 feet of the Thermacell E55.
What we didn’t like about the Thermacell E55
What was tricky about this device for me is that my kids are constantly on the move, and given the 20-foot protection zone, it meant they couldn’t go far without once again being vulnerable to mosquitoes. Which is to say, if you really want this thing to work, you need to stay put!
While I had also seen some complaints online about the battery life of previous Thermacell iterations, I had zero issues in this department. Whether I was using it for one or three hours, my E55 was up and running the entire time. What did irk me, however, is that the E55 didn’t include a plug-in adapter for the wall. I know, I know, this is not uncommon among tech devices these days, but given the increasing number of products in my house that need to be regularly charged, I really appreciate when a brand includes an adapter, eliminating the need for me to go hunting for one.
Another downside for me is that this is a product you have to keep investing in — those refills aren’t going to magically arrive at your house and pay for themselves! REI is currently selling a two-pack of 36-hour refills for $24.93, which will surely last you a long time, but is also an additional cost on top of the $40 you already shelled out. The refills’ lasting times are accurate — my 12-hour cartridge lasted exactly that long.
How it compares
I’ve said it before and I’ll say it again, bug sprays are the bane of my existence. The extreme odor and stickiness they come with often leave me feeling itchy and headache-bound.
In terms of other popular repellents, candles and tiki torches can get the job done, but their open flames are a constant source of stress, especially when kids are running around. And as I mentioned before, this thing is light-years more advanced than your grandma’s ol’ bug zappers.
If you’re looking for a more expansive repellent solution that can cover a much larger swath of space, consider Thermacell’s LIV Smart Repellent System ($699 to $899), a DIY solution that connects multiple repellers placed in your outdoor area to an app that can trigger the heat-activated repellents on demand.
Bottom line
The Thermacell E55 is almost too good to be true. Sure, it’s got a lot of shiny selling points. Portable? Check. Silent? Check. Invisible and odor-free? Check and check. And it’s affordable (-ish, when you consider the refills you’ll eventually have to buy) and sleek enough that most people will assume it’s a Bluetooth speaker.
But ultimately what makes it worth the purchase is that it works at repelling mosquitos from the area you’re sitting in, and from biting you — as long as you stay in that confined space for the duration of the time. Summer might be ending in a few weeks, but the temperatures aren’t going anywhere this fall, so trust me, the E55 is worth investing in.