Last updated on September 9th, 2024
Does your wifi slow down or disconnect every time you use the microwave? It’s not uncommon, and it has to do with the frequency overlap between your microwave and wifi signals.
Why Does a Microwave Affect Wifi?
While microwaves are generally well-shielded to contain the microwave radiation generated when running, there may be some minor leakage even in a brand new machine. Microwave ovens generate electromagnetic radiation at 2.45 GHz to heat food, which is very close to the 2.4 GHz microwave frequency used by Wifi. This proximity in frequency means that even a small amount of radiation leakage or electromagnetic interference (EMI) from the microwave can disrupt your Wifi signal.
Sidebar: Why Does Wifi Operate on a Frequency So Close to Microwaves?
Microwave ovens were developed in the 1940s, and engineers found that 2.45 GHz was ideal for heating food because water molecules absorb energy efficiently at that frequency, generating heat. Given the existing use of 2.45 GHz by microwave ovens, regulators recognised that it wouldn’t be practical for other critical or highly regulated applications. Because microwave ovens were already emitting in this range, allowing unlicensed devices like wifi to share the spectrum made sense, despite the potential for interference. As a result, the entire 2.4 GHz ISM band (from 2.4 to 2.4835 GHz) was made available for unlicensed, low power devices like wifi, bluetooth, and cordless phones in 1947.
The Impact of Microwave Leakage on Wifi Performance
Microwave ovens are of course designed to prevent microwaves from escaping, but small amounts of microwaves can still leak, especially around the edges of the door. Even brand new microwaves will have some leakage, because safety standards permit a small amount, and preventing all leakage in every case, would make a manufacturers product uncompetitive in the market. Especially in today’s market where microwaves are built to a price and available for less than $50, it’s hard to imagine that reducing leakage beyond legislated levels is a high priority.
International standards allow microwave ovens to emit up to 5mW/cm² when measured from 5cm away. This limit is safe for human exposure, but it’s a much higher power level than the typical emissions from a wifi router. In most countries, wifi routers are limited by law to emitting 100mW on the 2.4GHz band, which translates to a power density of around 0.36mW/cm² when measured at 5cm from the router, and around .1-1mW/ cm² when 1-2 metres away.
Even if a brand new microwave is leaking at only 10% of the allowed emission limit—around 1 mW/cm²—this interference signal is on par with the output of a wifi router. If the leakage is any higher, its easy to see how the leakage or electromagnetic interference (EMI) could easily affect the wifi signal or at the very least make it more difficult – and slower – for the receiving device to decode. In some ways its a miracle that every microwave does not cause significant wifi interference given the different incentives.
Sidebar: Why Routers can Coexist With Each Other
If a microwave emitting roughly the same amount of power as a router, in EMI, is enough to disrupt my wifi network, why don’t all the overlapping networks of my neighbourhood cause problems?
When you place two routers next to each other, or within range of each other, they can coexist without major issues because wifi routers are designed to avoid conflicts by using coordinated protocols. Technologies like channel allocation and CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) allow routers to operate on different channels or time their transmissions to minimise interference. This allows multiple networks to function smoothly even when they are physically close.
Microwaves, on the other hand, emit uncontrolled, broad-spectrum electromagnetic noise at 2.45 GHz, close to the 2.4 GHz wifi band. Unlike routers, which coordinate their signals, microwaves don’t follow any protocols, flooding the frequency range with noise that disrupts wifi signals. This uncontrolled emission is what causes problems, making microwaves different from two routers that can efficiently share the same space.
Guide to Fix Microwave Wifi Interference
If your microwave is interfering with your wifi, here’s the steps to take to resolve the issue.
1. Move Your Router Away from the Microwave
Increase the distance between your wifi router and the microwave. The farther the router is from the microwave, the less likely it is to experience interference. If possible, the router and microwave should be in different rooms.
2. Switch to 5GHz Wifi
If your router supports dual-band wifi, consider switching to the 5GHz band, which does not overlap with microwave frequencies. The 5GHz band is unaffected by microwaves and can significantly reduce interference. Many modern devices support 5GHz, so connect them to this band for a faster and more stable connection, but be aware that the 5GHz signal is less able to penetrate walls and obstacles and is only faster when closer to the router. As you move further away 2.4GHz is the better band for reliable connection.
3. Replace Your Microwave
If none of these solutions work and you’re still experiencing wifi interference, it might be time to replace your microwave. Although your microwave is designed to block most electromagnetic radiation, wear and tear over time – especially aging door hinges – can increase leakage. The slightest door misalignment, imperceptible to the human eye can be the cause of significant leakage and EMI. The older your microwave, and the rougher you have treated it, the more likely it is to be leaking a higher level of EMI.
Do Microwaves Disrupt Bluetooth? Yes, and Here's How to Fix It
Microwaves can also interfere with Bluetooth because Bluetooth operates on the same 2.4 GHz frequency band as Wifi. The magnetron’s emissions and any electromagnetic leakage from the microwave can affect both Wifi and Bluetooth, especially if your Bluetooth devices are close to the microwave.
1. Move Your Bluetooth Device Away from the Microwave
The simplest fix is to move your Bluetooth device farther away from the microwave. The farther your device is from the source of interference, the more stable the connection will be.
2. Keep a Clear Line of Sight
If possible, ensure there is a clear line of sight between your Bluetooth device and its connected source (like a phone or computer). Avoid positioning your devices near large metal objects or between the microwave and the Bluetooth source, as this can exacerbate interference.
3. Switch to 5GHz Wifi
If your Bluetooth device uses Wifi for streaming like smart speakers for example, switch your router to the 5GHz band to reduce congestion in the 2.4GHz spectrum. This will help prevent both Wifi and Bluetooth interference, but as discussed above, 5GHz
4. Upgrade to Newer Bluetooth Devices or Replace Your Microwave
If you continue to experience problems, consider upgrading to newer Bluetooth devices. Newer versions of Bluetooth have better interference management, which can reduce the likelihood of disruption.