Wouldn’t it be great if all you had to do to get rid of household pests was plug in a $10 device and wait? No need for spraying toxic pesticides or setting up poison traps to drive nuisance animal and insect pests
out of your home or garden. This is the appeal of using one of the many ultrasonic pest repellers that have invaded the market over the past decades. But are these seemingly miraculous devices an effective tool to get rid of pests or simply a waste of time and money?
What Manufacturers Say
“Turn your home’s wiring into a pest repellent force field. Patented digital technology repels rodents, roaches, ants & spiders.” This is the claim of one popular manufacturer
selling electromagnetic and ultrasonic pest control products said to eliminate pests from homes and other structures in 2 to 4 weeks by “sending a pulsating signal through or altering the field around the electrical wiring inside homes and other buildings”. Depending on the model, such devices “are effective within an area ranging from up to 800 square feet or up to 2,000 feet.”
The theory is that such a device can produce pulses of sound at very high frequencies (of more than 20,000 Hz), which is inaudible to humans, but will act as a deterrent in the event of pest infestations. This frequency is thought to cause convulsions, seizures, and even death in some pests or interfere with their ability to communicate with other members of their colony. Mice, cockroaches, ants, spiders, and even bed bugs are then supposed to leave the area causing such distress and start looking for a friendlier environment.
Some of the touted benefits of their products include:
- They are non-toxic, non-chemical, and safe methods to control almost any type of house and garden pests, including cats, raccoons, squirrels, and bats
- They are simple to install and easy to use: just plug in the device and it will immediately start annoying and driving away invaders
- Sounds emitted by these devices are not detectable by the human ear and will not interfere with TVs and other electronics
- Some devices will use randomized sound patterns to prevent pests from getting used to them
This sounds too good to be true, and according to scientific research, it is, in most cases. In 2001, more than 60 companies selling ultrasonic pest repellents received warning letters
from the Federal Trade Commission (FTC) stating that the efficacy claims of their products are not supported by scientific evidence. Since then, biologists, wildlife experts, and pest control professionals have concluded, after extensive observation and testing, that most of these sound emitters do little or nothing to repel or modify the behavior of targeted pests.
What Scientists Say
In a 2012 paper
published in the Journal of Economic Entomology
, researchers from Northern Arizona University tested four commercially available sound-based devices that claimed to deter bed bugs
. They created a testing arena containing two buckets connected by a middle chamber, one bucket with an ultrasonic device inside, and one empty. At the beginning of each experiment, the bugs were placed in the middle chamber, and the ultrasonic devices were turned on for half an hour.
When the scientists looked to see how bed bugs responded to the devices, they found the bugs were neither repelled nor attracted by the high frequencies emitted by the repellers. They simply had no reaction to a device that was supposed to affect their behavior and drive them away.
An older study
testing the efficacy of commercial ultrasonic devices for their ability to repel German cockroaches found that none of the devices they used demonstrated sufficient repelling activity against the pests. The findings failed to provide evidence that ultrasonic technology could be used as an effective pest control method to repel or eliminate German cockroaches.
Just like bed bugs and cockroaches, mice, ants, and spiders have shown no response to these devices in laboratory tests. Of the pests that do seem to be affected by the noise, some tests have shown that they soon become accustomed to the sound as they realize it is harmless. Even the few models proven somewhat effective in lab tests are unlikely to perform as advertised in real-life situations, where signal strength may be diminished or blocked by walls and furniture.
According to entomologist Michael F. Potter, PhD. from the University of Kentucky, cited by WebMD
, it is possible that some ultrasonic devices may actually attract more bugs: “Never have they [ultrasonic devices] proven themselves to be effective control tools. If anything, I would expect the bugs to utilize them as a haven, since they often emit small amounts of heat, which serves as a short-range attractant to bedbugs.”
What Does This Mean to Consumers?
If you’re dealing with a minor infestation and want to try an ultrasonic pest repellent, we recommend doing a bit of research beforehand. Start by looking at reviews from people who have bought the same product and were satisfied by it. However, keep in mind that plenty of testimonial data can be subject to the placebo effect, and some success stories can be the result of using sound devices along with trapping and other control methods.
Also, make sure you buy products only from reputable companies that have conducted independent experiments and can show proof of their products' effectiveness. If the product is indeed fully tested and proven effective, the company is likely to make the information public to potential buyers.
Homeowners with serious pest problems who don’t want to waste their time and money testing these devices should rely on a qualified pest inspector
to diagnose their particular pest problem and suggest practical and effective solutions for the long-term. Professional help is always the quickest and safest method of not only eliminating pests from your property, but also keeping them from returning in the future.
About the Author
Daniel Mackie, co-owner of Greenleaf Pest Control, is a Toronto pest control expert well-known as an industry go-to guy, an innovator of safe, effective pest control solutions, and is a regular guest on HGTV. Mackie, along with business partner Sandy Costa, were the first pest control professionals in Canada to use detection dogs and thermal remediation for the successful eradication of bed bugs. In his free time, he is an avid gardener.