We Tested the Flowtron BK-40D Electronic Insect Killer

We purchased the Flowtron BK-40D Electronic Insect Killer so our reviewer could put it to the test. Keep reading for our full product review.

Bugs are attracted to light, whether it’s outdoor lights on your house or the alluring light of an insect killer. If you dread being in your backyard because you loathe mosquito bites or swatting at flying pests, you may be considering an electric bug zapper. To see if Flowtron’s BK-40D Electronic Insect Killer could tackle a bevy of bugs, we tested this product for hours outside near a moderately wooded area. If you fear bugs and want to be free to enjoy our yard, find out if this insect killer is worth your investment.

Setup: Use straight from the box—with a hook

You can pull the Flowtron BK-40D Electronic Insect Killer from its shipping box, plug it in, and it will go right to work. The important thing you have to do first, however, is figure out a way to hang it. The unit comes with a strong metal loop at the top, and the bottom is slightly rounded so it cannot be rested on the ground. For the best performance, users will want to purchase a metal hook and secure to a tree or post before setting up the insect killer. 

We hung the zapper on a fence post hook that was previously used for a hanging plant. The hook extended out far enough from the post and fence that the zapper had space all around it when hanging.

Of course, we needed an outdoor-safe extension cord as well. The cord attached to this zapper is about 10 inches long, which we found wasn’t long enough to connect to the nearest power outlet. Be sure to secure all safety cords so they don’t become tripping hazards in your yard.

This zapper comes with a cartridge containing octenol, a chemical that attracts biting insects, but you do not have to use it if you don’t want to. If you want to use the lure, you can attach it to the bottom of the unit. It lasts about 30 days, according to the manufacturer, and you can order replacement lures for about $12.

In our tests, we used the bug zapper for one hour without the lure, and we attached the bait for the second hour. The bugs appeared to be equally attracted to the zapper, though the zapping action did seem to escalate the longer the lantern was on.

Design: A classic appeal

This bug zapper’s design is basic—a tapered polycarbonate lantern houses a bright, 40-watt ultraviolet bulb and electrified grid. As bugs near the light, they’re zapped by the grid. Some bugs fall through the bottom of the lantern. Some stick directly to the light. There’s no trap or tray to be cleaned. If bugs stick to the light, you can use a small brush to wipe them away.

We used a medium-bristled brush to scrub the outside of the zapper after use, and we used a smaller brush to clean between the grates. With the open bottom-design, however, the machine is considered self-cleaning; the bugs fall through so they won’t stick.

The lightbulb in this unit is very bright. It might be too bright for sensitive eyes, especially in dark environments. We had to position the unit away from where we sat so it wouldn’t be overwhelming during our tests. This is actually ideal, as this zapper will attract a lot of bugs, so you don’t want to be in the line of the insects coming into the machine.

Performance: Once warmed up, it’s a killing machine

It takes about 30 minutes for the bugs to find the light attractive once it’s turned on. But when they do, the zaps start coming. In two hours, this machine killed several dozen mosquitoes and smaller flying bugs.

This zapper covers a large area—up to one acre—so that allowed us to position it 15 feet from where we were sitting during the test. The high-powered jolt sometimes sends zapped bugs flying. If you’re too near the insect killer, you may be hit by a stray bug or two. We didn’t have one hit us, but in the dusk light, we did see a few get launched when they were zapped.

We noticed a significant improvement in pesky bugs while we tested this device. We also only had two mosquito bites, which was surprising in a humid, hot environment that is usually rich with the biting bugs. Also, we noticed a pile of bugs form at the base of the zapper. It’s important to make sure the area where you hang the unit is OK for a bug pile-up. Don’t put it near animal housing or water.

Safety: Grate around electrified grid protects, but take precautions

This unit is designed to keep little hands and noses away as best as possible, so you don’t need to worry too much about pets or children getting zapped by the insect killer. The exterior polycarbonate grid has small openings—big enough for bugs, but not big enough for most fingers. Hang the lantern higher so it’s out of reach of children. 

Price: Expensive, but worth it for large coverage

If you have a smaller yard or patio, you can probably purchase a bug zapper with less coverage for a lower cost. But if you’ve got a big area to cover, this bug zapper is a worthy investment. It also comes with a two-year limited warranty from the manufacturer.

Flowtron BK-40D Electronic Insect Killer vs. Aspectek Powerful 20W Electronic Indoor Insect Killer

We tested both of these zappers and found them to be equally powerful, but they cover different areas. The Flowtron Insect Killer can be used outdoors, but the Aspectek Insect Killer is meant for indoor use. If you have a serious bug problem, you could certainly use a combination of the two to keep your home free of pests.