Riddex has begun a new ad campaign (at least in our area) for their electronic pest control device called the Riddex Plus Digital Pest Repeller (tm). Since we get a lot of questions about these devices I thought it might be a good time to remind readers what the devices do, and don't do.
Marketers of electronic pest control devices (sometimes called ultrasonic pest control, or something similar) claim that these devices chase away insect pests and small rodents with electromagnetic and/or ultrasonic energy. They claim that laboratory tests have proven that the product works but they don't cite any actual studies. The only supporting documentation is testimonial.
I could not find a single published study in any scientific journal that supports the use of electronic pest control devices for household pests like spiders, cockroaches, or rodents. Such a study would be inexpensive to conduct and could potentially add a great deal of credence to their claims. Instead the only evidence given by the marketers is testimonials in which users submit their personal experiences with the product. Personal endorsements, or testimonials, tend to be clouded with bias for a variety of reasons. Scientific trials on the other hand are designed to eliminate this bias as much as possible.
If you want to purchase one of these devices to test in your home here's a suggestion: since I could not find a published study, call the company and ask them to send you a citation from a supportive study. Then, if you get a citation to a scientific study that supports the use of electronic pest control devices please send it to me, and I'll post it here for others to see!
I'm not picking on Riddex in particular because none of these devices, from any manufacturer, has been shown to work. My guess is that proper trials have not been done because the manufacturers know that the data would not be favorable to their products. So, until scientific trials are done by reliable labs and the results published in peer-reviewed journals I'd suggest you avoid these devices. There are now safe alternatives to conventional pesticides for virtually all household insect pests, and rodents can be managed with traps.
I have posted additional information about electronic pest control devices in general at our 'Bugs site including a link to an FTC warning about these devices.
In summary, there is no good scientific evidence that any of these devices work. If there was good evidence you can be bet that it would be plastered all over their ads, but it is not.