Longer, hotter summers means a longer mosquito season. If June's heat waves are any indication of what's to come, you better have a plan for bugs. I was winging it with fickle citronella and stinky bug spray until I discovered the Thermacell -- an affordable bug repellent diffuser that has kept my evenings almost completely bite-free since I started using it. The Thermacell works better than any mosquito repellant I've tried. David Watsky/CNET Massachusetts-based Thermacell makes a line of devices designed to keep mosquitoes at bay by misting the air around with an odorless chemical that keeps bugs from biting. I tested the smallest of its devices, the Thermacell E-series with fast charging dock, which defends pests in a 20-foot radius and costs just $40 on Amazon (currently on sale for $35), REI and other retailers. How does the Thermacell work? The rechargeable device releases a trickle of vapor, similar to an oil diffuser, that contains a synthetic version of a chemical found in the chrysanthemum flower. According to Griffin Dill, an integrated pest management professional at the University of Maine I spoke to, these compounds excite insects' neuroreceptors, which dissuades them from feeding. Because of this, you might still see bugs flying around but they're far less likely to bite you. Thermacell I also spoke with Thermacell's Senior Product Director Adam Goess, who performs research and testing in the company's sprawling laboratory in the swamps of Florida -- the mosquito capital of America. As of our speaking, they've found the device to be effective in deterring dozens of species of mosquitos and even black flies and biting gnats. In my testing, it worked just as advertised. I ran the Thermacell around my outdoor dining table and lounge setup on five evenings during twilight when bugs are particularly ravenous. My yard has a pool, so you can only imagine the sort of swarms that descend on the space during summer. Read more: Add These Bug-Repelling Plants to Your Kitchen Today Each time, friends and I waited until we felt the first bites and broke out the Thermacell, placing it in the middle. In all five instances, the bug bites stopped as the mist made its way out of the softball-sized device. While bites were neutralized, we could still see the occasional mosquito darting about. A few drawbacks Pods last for about 36 hours and each one costs $20. David Watsky/CNET Thermacells are fueled by small pods. Those last for about 36 hours when run continuously before you'll need a refill. Refill pods cost about $20, but I found a two-pack, good for 72 hours of repelling, for $22 on QVC. Needless to say I jumped on the deal. Considering the buggiest parts of the evening only last an hour or so, you can stretch a single pod for a month or more if you remember to turn it off when you're done or the bug hour is over. And only use it when you need it, not every time you hang outside. Also, the Thermacell only works when it's charged and not while charging on the dock. So if you've forgotten to charge it before the bugs come, there's no recourse or backup plan and you'll have to wait until it regains some juice. A Thermacell won't work while on its charging dock, so be sure that it's charged before the bug hour begins. David Watsky/CNET Though he hadn't tried the Thermacell himself, Dill said that he had heard good things from colleagues. He steered us away from a few other popular anti-mosquito products: