Wi-Fi networks use radio signals in either the 2.4 GHz or 5 GHz frequency bands. All modern Wi-Fi devices support 2.4 GHz connections, while some equipment supports both. Home broadband routers that feature both 2.4 GHz and 5 GHz radios are called dual-band wireless routers.Ach5 / Alison Czinkota
An important distinction to make is between a Wi-Fi network and a mobile phone's wireless network. These are two different technologies, and it can be confusing when discussing 5 GHz Wi-Fi frequency bands and 5G mobile networking technology, the replacement for 4G.5G & 5 GHz Are Different: Here's What They Mean
Here's an explanation of Wi-Fi networking that can be set up in a home using a router, the two frequency bands used, and how a dual-band home network can be set up to take advantage of both frequencies. This doesn't cover mobile networking technology for smartphones and other devices.
GHz and Network Speed
Wi-Fi networking comes in a few varieties. These Wi-Fi standards define improvements in networking technology. The standards are (in order of release, oldest to newest):802.11a802.11b802.11g802.11n802.11ac802.11ad
These standards are connected to GHz band frequencies but aren't discussed in detail here, but they are referred to.
A 5 GHz network can carry more data than a 2.4 GHz network and is technically faster (assuming the electric power to the higher frequency radio is maintained at a higher level). 5 GHz radios support higher maximum data rates in network standards 802.11n, 802.11ac, and 802.11ad. Home devices that generate or consume the largest amount of network traffic, like video streaming units or game consoles, generally run fastest over 5 GHz links.
GHz and Network Range
The higher the frequency of a wireless signal, the shorter its range. 2.4 GHz wireless networks, therefore, cover a larger range than 5 GHz networks. In particular, signals of 5 GHz frequencies do not penetrate solid objects as well as 2.4 GHz signals, and this limits the reach of 5 GHz frequencies inside homes.
GHz and Network Interference
Some cordless phones, automatic garage door openers, and other home appliances use 2.4 GHz signaling. Because this frequency range is commonly used in consumer products, it's become saturated with signals. This makes it more likely that a 2.4 GHz home network will suffer interference from appliances than will a 5 GHz home network. This can slow down and interrupt Wi-Fi network speed in these cases.
GHz and Cost
Some people mistakenly believe 5 GHz network technology is newer or more innovative than 2.4 GHz. This is because 5 GHz home routers became available after routers that use 2.4 GHz radios. Both types of signaling have existed for many years and are both proven technologies.
Routers that offer both 2.4 GHz and 5 GHz radios are generally more expensive than those offering only 2.4 GHz radios.
The Bottom Line
5 GHz and 2.4 GHz are different wireless signaling frequencies that each have advantages for Wi-Fi networking, and these advantages depend on how the network is set up — especially when considering how far and through what obstructions the signal may need to reach. If you need a lot of range and a lot of penetration through walls, 2.4 GHz is going to work better. However, without these limitations, 5 GHz will likely be a faster choice.
The dual-band hardware like that found in 802.11ac routers combines the best of both types of hardware by integrating both types of radios. This is an emerging preferred solution for home networking.