Sonic Rodent Repellent

Sonic or ultrasonic devices have been touted as repellents for everything from roaches to insects to rodents, specifically rats and mice. There are multiple brands of these electric devices that are said to emit either a sonic or ultrasonic wave, which these pests allegedly find irritating. These devices are so common that they are advertised on television and in magazines plus are offered in specialty stores.  Some are sold specifically to repel rodents. However, there is no evidence whatsoever that these devices repel insects or are effective in rodent control.

Rats and mice emit high pitched sounds and may communicate using these sounds. Devices that use sound that humans can hear typically have no effect on the rodents. This frequency range is from less than 100 hertz to just over 20,000 hertz, or 16-20 kilohertz (kHz). Sonic devices are also used to deter birds, but there is only temporary relief, if any. In fact, in areas with large populations of birds, birds have been observed roosting on top of sonic units. Humans can hear some sounds heard by rats and mice; however, much of the rodents’ hearing range is above the human range. This range outside of human hearing is called “ultrasonic.”

Rats can hear up to 80 kHz, which is much higher than the frequency heard by humans.  Rats can hear a frequency as low as 200 Hz. Mice have a slightly different range of up to 91 kHz and as low as 1,000 Hz. The theory of ultrasonic repellers is to create a sound irritating to rodents, but yet at a frequency out of the range of human hearing.

Even though sound may be created that can be heard by rodents and not heard by humans, these sounds have not been shown to repel rodents. In fact, there are no scientific studies which show that these devices will keep a large area free from rodents.

There is some possibility that future repellers will work in small areas, but most of the units available to the homeowner have limited to no value. Consumer protection agencies of the government including the Federal Trade Commission have issued warnings to companies producing these products that the units must work; however, enforcement has been lacking.