Studies have revealed varying results as to whether or not ultrasonic pest repellents work. For example, they do not seem to have much of an effect on cockroaches, and they are not effective at getting rid of spiders or ants. Some of the tests have even revealed that pests can eventually become used to the noise, which means that this form of pest repellent stops becoming any kind of a deterrent. Another problem that can prevent the device from working is if there is furniture or walls blocking the high frequency sounds from travelling.
Keep in mind though that there are many people who claim they work very well, so it’s really a case of researching different brands of ultrasonic pest repellents and reading reviews. Remember, as we have mentioned, if the sound is not blocked by things like furniture, then it’s more likely to be effective.
If the pest infestation is particularly bad, you will most probably need something more than a ultrasonic pest device. It may be best to hire someone to locate the source of the problem and have it properly treated or, you might need to consider using more proven effective pest repellents.