Electrical appliances can interfere with Wi-Fi signals, but the amount of current running through decorative lighting is almost always too low to be troublesome — unless, of course, you stick a finger into a socket.
The related rumblings started modestly enough, with a brief mention in a press release that announced a Wi-Fi speed-check tool from Ofcom, a British agency that regulates Internet. The release noted that Wi-Fi connection issues could be related to "something as simple as interference from other electronic devices, such as a microwave oven, baby monitor, a lamp — or even Christmas fairy lights," which is apparently Brit-speak for Christmas lights.
Tech news tends to be slow this time of year, so the story hit Google News and took off from there. Of course, many electronic devices can actually interfere with your home Wi-Fi network. Here are some tips to avoid interference issues.
The science is simple: Wi-Fi is electromagnetic radiation. Electrical appliances and their cords generate electromagnetic fields, and they can cause interference when electromagnetic waves try to travel through them. If your Wi-Fi signal passes through an electromagnetic field, it can be disrupted or weakened.
The stronger the field, the greater the disruption to Wi-Fi. The worst and best known offender is the microwave in your kitchen. If a router or an access point is located near a microwave, performance will likely suffer.
Cordless phones are also problematic, as well, and they're often more of an issue because you're more likely to have a portable phone on your desk than a microwave. Water pipes can also cause interference, because water absorbs radio waves.
Walls don't generate electromagnetic fields, but they do can weaken Wi-Fi signals that pass through.
A few technologies exist that let you extend the range of your Wi-Fi network. I've had good luck with a technology called Powerline, which amplifies signals using the copper wiring in your home's walls. You can also buy range extenders, made by any number of vendors, that amplify and relay your signal.
The setup for both of these systems can be tricky, however, so it's a good idea to first try moving your router around or switching channels, to see if you can improve the signal without the effort and expense of another piece of hardware.