Do Ultrasonic Pest Repellents Work? Best Outdoor Ultrasonic Pest Repeller

Ultrasonic pest repellers are small devices that emit an ultrasonic frequency, part of the audio spectrum humans cannot hear. The idea is that these frequencies will be bothersome to pests, but inaudible to humans. They’re supposed to control pests while causing no harm to people. But do ultrasonic pest repellers actually work, and if so, which ones are the best?

Do Ultrasonic Pest Repellents Work?

There are almost no studies suggesting that ultrasonic pest repellers work. If you like your devices to be backed by actual studies (which we very much do!), then you should consider some other pest control options like the ones at the bottom of this article.

It is quite clear that various animals commonly classified as pests, such as rats, mice, and rabbits, and insects can hear in the ultrasonic spectrum. Humans cannot hear in this spectrum. But that doesn’t mean these pests are bothered by ultrasonic frequencies, or that these devices control pests.

Some will even claim they will deter birds, but birds cannot hear ultrasound.

The FCC has complained about the advertising and claims of many of these companies, and some have had to refund money to buyers. Buyers should be wary of these companies.

That said, many people who employ these devices report success in keeping pests away while they’re active. They emit no harmful chemicals, smoke, fog, and the like, and are relatively harmless.

Pest control is as much an art as a science. Determining what is effective in your circumstances can be tough, and so much of pest control, in general, ends up being received folk wisdom.

Our opinion is that an ultrasonic repeller is likely not your best option for pest control, though there are very few downsides to them if you want to try one out. They’re cheap, and as we said, there are many who have positive experiences with them. We’ll look at some of the science, and some of the models, in this article.

We’ll also consider other options for more traditional pest control at the end of this article.

What Are Ultrasonic Rodent Repellers Supposed to Do?

There are pretty wide-ranging claims suppliers of UPRs throw out there. They will repel cats, mice, squirrels, wasps, bed bugs, roaches, gophers, coyotes, etc. Yes, all of those animals can hear in the ultrasonic range (birds cannot hear in ultrasound). But it’s not at all clear that the frequencies emitted by these devices will actually deter the animals from doing anything.

Some suggest that a sweeping frequency is more effective than a single constant tone, but again, there are no studies showing that these are successful. And some repellers use multiple tactics like flashing lights, noises, etc. to send pests away.

And if they are successful at repelling pests, are they repelling bees and flies that are pollinating your garden? There’s a lot of magical thinking that goes into an ultrasonic pest repeller, and the idea that a little box will be able to keep away the animals and insects you don’t like, while not bothering the ones you do like is a bit too much.

As McGill University puts it, “Some studies conducted in perfect laboratory conditions show that ultrasonic sound can be fatal to certain species by critically increasing their body temperature or causing audio-induced seizures. So the humane notion of pests simply scurrying out of your garage with a massive headache isn’t quite right”.

It should be noted that these studies that did find an impact on pests used very very high-powered devices, not consumer-grade devices.

Potential Harms of Ultrasonic Emitters

There are a few potential harms that may be associated with ultrasonic emitters. These harms are certainly much less concerning than, say, pesticides.

Impact on Cats, Dogs, and Domesticated Animals

Cats and dogs can both hear into the ultrasonic range and may be bothered by emissions by these devices. Pet hamsters, rabbits, and other small animals can hear ultrasonically and may be bothered by these devices.

Impacts on Children

Children have better hearing ranges than adults do. Many children can hear over the 20,000Hz line that is typically the crossover point between standard sound and ultrasound. Consequently, these ultrasound emitters may bother young children, who may be able to hear the tones.

Interference with Hearing Aids

Some have found that these ultrasonic devices can interfere with hearing aids. If you have a loved one with hearing problems, you may be negatively impacting the effectiveness of their hearing aid with an ultrasonic emitter.

Interference with Burglar Alarms

You generally want your burglar alarm to work properly! You don’t want it to go off inadvertently, nor do you want it to be ineffective at sending an alert if there is a genuine problem.

This is likely less of a problem with an outdoor pest repeller than an indoor version.

An Indiscriminate Solution

Animals eat other animals, animals eat insects, and insects eat each other. If you end up repelling, for example, bats, you may find that you actually have more pesky mosquitoes than you otherwise might because the bats are no longer eating the mosquitoes.

Ultrasonic emitters are a grenade-style solution, and in your quest to repel pests, you may end up repelling the creatures that keep the pests away, making your problem worse!

The Umwelt

One of our favorite concepts is the idea of the umwelt. The umwelt is essentially the collection of senses a given animal has, through which that animal experiences their own slice of reality. Each species of animal has its own umwelt. Many animals can hear in the ultrasonic range, while humans cannot. Many animals can see infrared, while humans cannot. And some animals, like sharks, can detect electric signals. These are all aspects of the umwelt for each animal.

The idea of an ultrasonic repeller is that if you can find an annoying tone that is broadcast in a frequency that is annoying to creatures you see as pests, while not bothering creatures (such as humans!) you don’t see as pests, then you’ve found a great tool.

Ultrasound and Hearing

When it comes to sound, humans generally can hear from about 20Hz to 20,000Hz. Ultrasound is considered to be essentially all frequencies above 20,000Hz. Humans can’t hear much above 20,000Hz, so any annoying noises above that frequency may work great at bothering animals and insects, but won’t impact humans.

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What Animals Can Hear in Ultrasound?

Here are a few animals and insects commonly classified as pests that can hear in ultrasound. As we mentioned above birds do not hear ultrasound.

Bats
Moths
Mice
Grasshoppers
Squirrels
Cats
Dogs
Gophers
Rabbits
Raccoons
Many other animals

See this chart for more information.

The Difficulty in Determining the Effectiveness of Ultrasonic Emitters

Many people consider ultrasound to be a bit like magic. It’s a set of frequencies that we know exist, and we know that other animals can hear, but we cannot. But to those animals, ultrasound is, well, just sound. If you’re considering purchasing an ultrasonic pest repeller, a good place to start may be to ask yourself if non-ultrasound would be likely to repel pests?

Let’s say you cranked up some Metallica, would that keep pests away? If not, why would you think that an ultrasonic frequency would? Again, to animals who hear ultrasound, loud music in the range of human hearing would be experienced in the same way as ultrasound would.

The only benefit to broadcasting in ultrasound is that humans won’t have to listen to it!

The one caveat to this is that some animals may use ultrasound frequencies for location and navigation, and some may use ultrasound to communicate. By flooding the area with ultrasound, those insects and animals may be more heavily impacted than those who can hear these frequencies but aren’t using them, in particular, to communicate or navigate.

Pros and Cons of Outdoor Ultrasonic Pest Repellers

Let’s consider the pros and cons of these devices.

Pros

Inexpensive
Relatively little harm to humans
No poisons or chemicals needed
Fairly safe to use around kids
Does not use much electricity
Does not cause any significant harm to animals

Cons

Maybe complete voodoo, and not do anything to pests
Very difficult to determine their impact
Indiscriminate, cannot distinguish pets from pests. May deter beneficial creatures
Sound waves are blocked by inanimate objects

Best Outdoor Ultrasonic Pest Repeller

We’ve looked at several ultrasonic pest repellers listed on Amazon, and found many of them to be a complete joke. Many are filled with fake reviews and the like. Virtually all of them have their detractors, but some are particularly egregious and should be avoided.

We’ve picked three outdoor models that show at least some promise, and are given “A” ratings on their reviews from Fakespot.

Out of all of the repellers reviewed here, the one most worth trying is the PREDATORGUARD Pestaway Repeller. This repeller is simple, easy to use, and easy to clean. It uses a motion sensor to trigger a combination of ultrasonic frequencies and sounds within the range of human hearing, along with LED lights. This combination means that it has multiple ways to scare off unwanted visitors to the yard. This suite of broadcasting mechanisms, combined with a motion detector, makes the PREDATORGUARD Pestaway the best outdoor pest repeller to try.

It includes a 12-month warranty, which is always a plus.

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Ultrasonic Pest Repeller Reviews

You should be skeptical of an ultrasonic pest repeller, and be prepared to return it in less than 30 days if it’s not effective in solving your problem. We would suggest you start by purchasing only one — don’t buy five of these things to start with.

And your best bet is to pick a repeller that doesn’t just emit ultrasound, but also one that flashes lights and potentially sounds within the range of human hearing. A suite of effects is more likely to repel pests than ultrasound alone.

Here we’ll look at three decent options that don’t seem to be filled with fake reviews and have several reports of success. Of course, all have several reports of failure, too, so keep that in mind!

After this section, we have a few other options for pest control that may be more effective.

1. PREDATORGUARD PestAway Ultrasonic Outdoor Animal Repeller

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Key Points at a Glance

Easy to Install
Waterproof
Motion-Activated
Uses Light and Sound
Combines Light, Sound, and Ultrasound as a deterrent
Battery-Powered
AC Power Adaptor Included
12-Month Replacement Guarantee
Non-Toxic

Dimensions

Effective Up to 12 Meters
Weighs 12.5 oz.
Product Dimensions: 4.9 x 4.4 x 4.3 in.

The Details

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The PREDATORGUARD PestAway Ultrasonic Outdoor Animal Repeller is a small, compact black box that combines ultrasonic and sonic technologies with a flashing strobe light and sudden, high-pitched noises to scare away nuisance animals like rats, mice, gophers, deer, and stray cats and dogs.

The PestAway looks like an old-school Kodak camera and is pretty small. Set it up and wait. PREDATORGUARD suggests this device is effective up to a range of about 30 feet at a 40-degree angle.

The PREDATORGUARD repeller is easy to install but doesn’t come with a stake or any other sort of base. The device is waterproof to prevent damage, though if you can, it is probably a good idea to shelter it under something to keep water away from it as much as possible.

Each PREDATORGUARD Repeller comes with a 12-month replacement guarantee, where the manufacturer is willing to send a new product free of charge if something happens to the original.

This device is battery-powered (two 9v batteries), though buyers can choose to pick up a power adaptor if the user wants to plug it in instead.

AC Power Adaptor for PestAway Ultrasonic Animal & Cat Repeller (Does Not Include Pestaway Repeller - This is a Seprate Product)

input: 110-240V 50/60 Hz 0.2A; output: 9V DC 0.2A, 72 inch cable length (male connector); Ensures your PestAway device never runs out of power

Last update on 2025-06-27 / Affiliate links / Images from Amazon Product Advertising API

The lights and high-pitched sounds are triggered by a motion sensor, so they are not flashing all the time. A guidebook is included that explains at what height to place the ultrasonic pest repeller to deter certain animals. For example, 1-2 ft. is ideal for stray cats.

The Bottom Line

The PREDATORGUARD is a great ultrasonic pest repeller that seems to have some effect on cats and other animals. It may well be your best option to try to start with. Many users report success with this system.

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