Do Ultrasonic Pest Repellers Actually Work?

Not reliably. Rodents may react to the sound briefly but habituate quickly, and the waves don't pass through walls or furniture. Sealing entry points and trapping is what actually controls a rodent problem.

There's no solid evidence they do. University of Arizona Extension found that commercially available sonic devices for home use have not been shown effective in scientific studies, and the devices don't touch the food, moisture and harborage that keep insects around.

Customer reviews are not controlled tests. Pest activity can rise and fall on its own, and UC IPM notes that rodents startled by an unfamiliar sound quickly become accustomed to it, so a device plugged in during a lull can look like it worked. University of Arizona Extension, reviewing the scientific studies, found that commercially available sonic devices for home use have not been shown effective.

The claims are widely overstated — enough that the FTC has warned manufacturers. They're unlikely to solve a real infestation, so treat them as no substitute for actual pest control.

Exclusion — sealing the gaps pests enter through — plus removing food and water and treating where they hide. Those address why pests are there in the first place, which a noise device never does.

No. A 2007 Cochrane systematic review of 10 field studies concluded that electronic mosquito repellents have no effect on preventing mosquito bites. That review covered electronic devices rather than phone apps, and we know of no study showing an app does better. Dumping standing water and using an EPA-registered repellent such as DEET or picaridin on skin is what works. Mosquitoes are not an ExterMetro service; in the San Gabriel Valley, the San Gabriel Valley Mosquito and Vector Control District, (626) 814-9466, is the local agency to call.

Yes. In May 2001 the Federal Trade Commission warned more than 60 manufacturers and retailers that claims about eliminating rodents or repelling insects must be backed by competent and reliable scientific evidence, after bringing enforcement actions against six companies between 1985 and 1997.

No. UC IPM notes that ultrasonic sound is directional, doesn't penetrate behind objects and loses intensity quickly with distance, so walls, floors and furniture block it and a device reaches, at most, the open air of the room it is plugged into. Rodents in the attic or wall voids are beyond its reach.

There is no evidence they do. Spiders follow the insects they eat, so vacuuming webs, sealing gaps and keeping outdoor lights off the house, which UC IPM notes draw insects and then spiders, does far more.

University of Arizona Cooperative Extension reviewed the research and concluded that commercially available sonic devices for home use have not been shown effective in scientific studies; UC IPM says rats quickly become accustomed to repeated sounds and that sound devices have very limited use against mice.

There is no good evidence they do. UC IPM's house mouse guide says there is little evidence that sound, magnetic or vibrational devices of any kind will drive established house mice or rats from buildings or provide any prevention or control. What works is trapping the rodents already inside and sealing every gap 1/4 inch and larger.

No. UC IPM says rats quickly become accustomed to repeated sounds, and ultrasound does not penetrate behind objects, so rafters, insulation and stored boxes shield the rats from it. Roof rats in an attic are handled by trapping and by sealing openings, including those above ground level, since UC IPM notes roof rats are excellent climbers. We trap and seal in the same visit, with a one-year warranty on the exclusion work.