Slow WiFi at home is hugely frustrating. Before calling your internet provider, there are several things you can check and improve yourself.
Is it the WiFi or the internet connection?
Connect a computer directly to the router with an Ethernet cable and test the speed at speedtest.net. If it's fast over cable but slow over WiFi, the wireless network is the problem. If it's slow over cable too, the issue is your provider's line.
Causes of slow WiFi and how to fix them
1. Distance and obstacles from the router
WiFi signal weakens with distance and obstacles, especially thick concrete walls. If the router is far away, use a WiFi extender or a mesh network system.
2. Interference: switch to the 5 GHz band
2.4 GHz routers share frequency with microwaves and neighbours' routers. Switch to the 5 GHz band if your router and device support it — it's faster and has less interference, though shorter range.
3. An old or low-quality router
Routers supplied by internet providers are sometimes low quality. A decent mid-range router (€50-80) can dramatically improve coverage and speed.
4. Too many connected devices
If lots of devices are on the WiFi at once, bandwidth gets shared out. Modern routers with MU-MIMO technology handle simultaneous connections better.
5. A congested WiFi channel
In buildings with lots of routers, many can end up on the same channel. Change the WiFi channel in your router settings. Apps like "WiFi Analyzer" (Android) show which channels are most crowded.
The definitive fix: an Ethernet cable
For fixed devices (desktop PC, smart TV, games console), a wired Ethernet connection is always more stable and faster than WiFi. If running a cable isn't practical, powerline adapters (using your home's electrical wiring) are a good alternative.