Yes, they do. Microwaves and radio waves are physically the same things, i.e., both are forms of electromagnetic radiation. Some microwave radiation can leak out and interfere with WiFi signals.
If you have a microwave, then you have probably observed that when it’s up and running, you may simultaneously experience problems in loading web pages on your smartphone, laptop, or any other internet-enabled device. This is especially true if your router and microwave are in close proximity to each other.
Why does that happen? Why does switching on the microwave hamper your WiFi connectivity?
Like most things related to ‘electric signals’, its answer starts with the following term: electromagnetic radiation.
We are basically surrounded by electromagnetic radiation all the time. Visible light, something that bathes every single thing around us, is a form of electromagnetic radiation. Similarly, many other things work via electromagnetic radiation, including cell phones, TV remotes, microwave ovens, WiFi, and much more.
Electromagnetic radiation comes in different types, depending on its frequency. Gamma rays and X-rays have high frequencies (and thus high energies), while radio waves and microwaves are on the other side of the band, as they have lower frequencies. You may recall the following diagram of the electromagnetic spectrum from your high school science class.
Microwave ovens and WiFi routers
As mentioned, many everyday appliances rely on electromagnetic waves to function. Two of the most common household appliances are microwave ovens and WiFi routers, both of which emit electromagnetic rays in order to function; microwave ovens emits microwaves to heat up food, while WiFi routers emit radio waves.
Microwave ovens convert electricity to electromagnetic waves of larger wavelengths called microwaves. These microwaves are radiated inside a tightly sealed metal box. Theoretically, these waves bounce back from the wall and should not bypass the wall.
Although it is still not quite clear how the heat is distributed throughout the food being subjected to the waves, microwaves are known to be extremely adept at exciting and vibrating water molecules, and most natural food has some water constituent in it.
These microwaves lead to vigorous motion of the water molecules, creating intermolecular friction, which generates the heat to cook the food.
A clash of frequencies
If you are a science geek like us, on a perennial quest to find causation and correlation between almost anything that exists, you might have observed that the moment you stuff your food inside the microwave oven and turn it on, your WiFi internet connectivity becomes erratic.
In some cases, it might be that your device ceases to connect at all, but after you turn off the microwave oven, the internet connectivity goes back to normal.
If you haven’t observed this, try it for yourself. Place your WiFi modem and microwave in close proximity and turn on the microwave. Install some internet speed-testing apps like Speedtest by Ookla. Try to heat water in the microwave oven and check your internet connectivity as the microwave oven runs. You’re likely to see connection issues or speed degradation… but why does this happen?
Well, the reason behind this problem lies in the frequency of operation, which overlaps between your WiFi modem and microwave oven. They both generally operate at a frequency of around 2.4 GHz. However, microwave ovens, unlike WiFi modems, do not transfer any data, but instead radiate signals in the unlicensed 2.4 GHz ISM band (Industrial, Scientific and Medical band).
As we stated earlier, in theory, a well-shielded and branded microwave oven should not let microwaves escape from within its metallic boundaries. It should, in principle, prevent all the microwave radiation generated inside the oven from escaping to the outside, but in reality, that’s not what happens.
Some microwave radiation leaks out and interferes with WiFi signals (i.e., radio waves of the frequency 2.4 GHz). Note that this interference (at 2.4 GHz) is caused by commonly used WiFi devices (e.g., WiFi routers, smartphones, cordless telephones, Bluetooth devices, and so on) that work on 802.11a and 802.11g standards. Some other devices that can cause similar interference include electric blankets, electric bug zappers, toaster ovens, etc.
Is this interference dangerous?
Obviously, mixing and mashing electromagnetic waves emanated from the WiFi device and leaked from microwave oven might make us nervous if it could damage the appliance. Fortunately, that’s not the case and you shouldn’t worry about your appliance or gizmo getting damaged from this interference of electromagnetic waves. Remember, it’s not the actual devices that are mingling, just the waves coming off them.
When it comes to irradiation, again, you shouldn’t really be worried, as we’re all surrounded by gizmos and appliances that constantly emit these high-frequency electromagnetic waves, including our smartphones, computers, home appliances, power lines, baby monitors, etc. Only if your microwave completely chokes the internet, despite the WiFi router being several meters away, should you be concerned enough to contact the manufacturer for replacement/repair.
How to fix the interference between microwave and WiFi signals?
The best solution to this problem would be upgrading your WiFi equipment to a system that works in the 5 GHz band (modern 802.11n routers operate in this band), rather than in the 2.4 GHz range.
You see, 2.4 GHz and 5 GHz are two bands that your router can use for its signals. The advantage of using 5 GHz is that not only does it prevent interference from the aforementioned devices that operate in the 2.4 GHz band, but it is also capable of supporting better connectivity (to the order of more than 1,000 Mbps). However, the operating range of a 5 GHz router is smaller than one operating at 2.4 GHz.
Another way to minimize interference is by keeping the microwave a few meters away from the router. Also, as water is a good absorber of electromagnetic waves, if you have a fish tank, it should also be kept a few meters away from the router.
Finally, an inexpensive thing that you can do to improve this situation is to pause your “Internet work” while your microwave is still switched on. Or, simply get used to your Internet behaving badly when you’re browsing the web next to your switched-on microwave. The best thing about microwaves is that the interruption of your connectivity should rarely last longer than 2 minutes!