Ultrasonic pest repellers are electronic devices designed to deter pests by emitting high-frequency sound waves that cannot be heard by humans and most pets but are said to be highly irritating to some pests.
These compact units are typically plugged into standard electrical outlets and operate by emitting high frequency sound waves that are imperceptible to the human ear, generally ranging from 20,000 Hz to over 65,000 Hz.
But do they work?
What the Science Actually Says
Most scientific studies have found commercially available ultrasonic pest repellents to be largely ineffective, with researchers at Kansas State University testing three devices in 2002 and finding that none were able to repel ants in field or laboratory trials. One extensive test performed by Kansas State University in 2002 found that the devices were effective at repelling some insects, such as crickets, but the same devices had little effect on cockroaches, while ants and spiders were unaffected by any of the devices.
Testing found that ultrasonic devices produced less than 19.5% repellency against Australian paralysis ticks, with the low-level repellency meaning that they cannot be recommended for prevention against tick bite. Studies conducted in perfect laboratory conditions show that ultrasonic sound can be fatal to certain species by critically increasing their body temperature or causing audio-induced seizures, but due to the variable nature of pest invasions, these findings have not been replicated in actual homes.
Why Don’t They Work in Real Homes?
Ultrasonic waves do not pass through walls or furniture, meaning each device can only affect a small, open area, and some pests may initially be startled by the sound but quickly adapt, returning once the disturbance is no longer perceived as a threat. Research from Kansas State University found effectiveness drops by 50% just six feet from devices in furnished rooms compared to laboratory settings.
While the high frequency sound emitted might startle certain pests the first time they hear it, many pests will grow accustomed to the noise once they realize the noise is harmless and ignore it. This adaptation process, known as habituation, occurs within days to weeks.
Legal Issues and FTC Warnings
The Federal Trade Commission sent warning letters to more than 60 manufacturers and retailers of ultrasonic pest-control devices in 2001, stating that efficacy claims about those products must be supported by scientific evidence. In 2003, Global Instruments and its president agreed to settle FTC charges that they made unsubstantiated claims about the effectiveness of their electromagnetic and ultrasonic pest control products.
Class action lawsuits continue to be filed against these companies, including a multi-million dollar suit that began in 2015 against Bell & Howell, where the plaintiff provided photo evidence of rodents resting on ultrasonic pest-repeller plug-ins, arguing the devices had no effect in deterring pests.
Safety Concerns and Side Effects
Ultrasonic noise can cause distress in pets such as dogs, cats, rabbits, guinea pigs, and hamsters, with possible signs of distress including confusion, whining or barking, or overall nervous disposition. Pets with sensitive hearing might be affected by high-frequency sounds, as rats, mice, and hamsters can hear sounds up to 90 kHz, cats can hear up to 60 kHz, and dogs can pick up sounds up to 40 kHz.
Safety concerns have arisen, with some users reporting that the sound can weaken the clarity of telephone conversations, interfere with burglar alarm systems, and cause muting in hearing aids.
What Actually Works for Pest Control
Effective long-term pest control includes exclusion by sealing off access points such as foundation cracks and entryways, sanitation through regular cleaning of food prep areas and trash bins to reduce attractants, monitoring using traps and professional inspections, and targeted treatments using safe, approved products when necessary.
Professional-grade baits are highly effective, with ant baits containing ingredients like borax, hydramethylnon, and indoxacarb allowing ants to carry poison back to the colony and eliminate the entire infestation at the source. Snap traps provide instant results for rodents and are chemical-free, while bait stations are ideal for large infestations and hard-to-reach areas.
Are There Any Benefits to Using Them?
Despite the overwhelming scientific evidence against their effectiveness, ultrasonic pest repellers do offer a few limited benefits that explain their continued popularity:
Safety and Peace of Mind: Ultrasonic pest repellers are generally considered safe for most household pets, as the sound waves they emit are above the hearing range of humans, cats, and dogs. The great thing about this device is that it is safe to use with cats and dogs as they won’t be able to hear nor feel a thing – giving you peace of mind that your beloved pets are safe from harm.
Environmental Benefits: These devices use soundwaves instead of dangerous chemicals or harsh poisons, making them an eco-friendly alternative to chemical pest control for those seeking non-toxic solutions.
Ease of Use: The device is generally small, pluggable, and easy to set up, so almost anyone can benefit from using one. Placing the repellers around your home is not only quick and easy but also does not require extensive know-how from the consumer.
Limited Effectiveness Against Specific Pests: One extensive test performed by Kansas State University in 2002 found that the devices were effective at repelling some insects, such as crickets, but the same devices had little effect on cockroaches, while ants and spiders were unaffected by any of the devices.
Psychological Benefits: Nevertheless, many users have reported success, which may be partly due to the placebo effect – we initially believe that it is working while it might be doing nothing and it was just probably just a slow day for the pests.
However, these limited benefits must be weighed against the fact that even when pests show initial aversion, they soon become habituated as they realize the noise is harmless, and the devices do not address the root causes of pest infestations.
The Bottom Line
Scientific studies show commercially available sonic devices to be ineffective, while devices developed by researchers demonstrate positive results but have yet to be marketed. The success of research devices is likely attributed to the development of techniques and devices that target specific species, often using biosonic sounds derived from organisms rather than generic computer-generated tones.
Instead of relying on ultrasonic pest repellers, homeowners should look toward proven pest control methods that focus on prevention, inspection, and targeted treatment, or consider hiring professional pest control companies for effective results.
