For decades, desperate homeowners have invested in electronic devices advertised to repel pests ranging from mosquitoes to rats to deer. Most promise to repel pests provided that specific instructions are followed in placement and multiple units and supplementary methods are employed. Most cite laboratory research to back their claims.

On the Other: If It Sounds Too Good...

Although certain high frequency sounds are annoying to insects and mammals alike, most are able to either acclimate or avoid the sounds by operating behind sofas, trees or other solid objects that block the sounds. The Federal Trade Commission has investigated numerous devices, and academic researchers perpetually debunk claims.

Bottom Line

Although many devices cite anecdotal evidence, scientific studies fall uniformly into the camp that considers the devices ineffective. The expense of the devices combined with the need for multiple units makes some systems prohibitively expensive. Since most ultrasonic repellers suggest backup, the sensible choice may be conventional pest control methods.

Source:

Federal Trade Commission: Complaint Against Global Instruments

Rat Sensory World: What Do Rats Hear?

Victorpest: Rodent Repellent Advantages

Resource:

Washington State University: Ultrasonic and Subsonic Pest Control Devices

University of Nebraska: Considering Ultrasonic Pest Control Devices? Save Your Money

Federal Trade Commission: Warning to Manufacturers and Retailers of Ultrasonic Pest-Control Devices