Multiple independent scientific studies have consistently found that commercially available ultrasonic pest repellers have no significant repellent or killing effect on various pests (cockroaches, mosquitoes, mice, ants).
The high-frequency nature of ultrasound means its penetrating power is very weak — it cannot penetrate walls, furniture, or even a pile of clutter.
Pests may initially show brief discomfort and avoidance but typically become habituated and return within a few days.
Federal Trade Commission (FTC) has taken enforcement actions against multiple companies claiming their ultrasonic repellers are effective.
Laboratory testing by the Australian consumer association Choice reached the same conclusion.
If ultrasound were truly effective at repelling pests, the pest control industry would have adopted it on a massive scale long ago.
The popularity of these devices stems mainly from clever marketing rather than scientific evidence.