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Why is my wifi slow in only one room?

What blocks a signal, how to confirm it is the wifi rather than the broadband, and the fix that suits each cause.

Difficulty
beginner
Time
30 min
Read
2 min

Short answer

Test the speed next to the router and in the bad room. If it is fast at the router and slow in the room, it is a wifi coverage problem — not your broadband — and the fix is a mesh system or a wired connection, not a faster package.

This is the most common home network complaint, and the most common wasted money: people upgrade their broadband package when the bottleneck is the last ten metres inside the house. One test tells you which it is.

Step by step

  1. Test next to the router first.Run a speed test standing beside it. That is what your broadband actually delivers. Anything slower elsewhere is a wifi problem, not a broadband one.
  2. Test in the bad room, on the same device.Same device, same test, so the comparison is fair. A big gap confirms coverage.
  3. Identify what is in the way.Brick and stone walls, foil-backed plasterboard, mirrors, radiators, water tanks and underfloor heating all block wifi badly. Two solid walls is often enough to kill it.
  4. Move the router if you can.Central, high, out in the open. Routers are usually installed wherever the phone socket is, which is frequently a hallway corner behind a cupboard — the worst place in the house.
  5. Try the 2.4GHz band in that room.It travels much further through walls than 5GHz, at lower peak speed. For a distant room, a slower signal that arrives beats a fast one that does not.
  6. Change the wifi channel if neighbours are close.In a flat or terrace, everyone's wifi competes. Most routers can scan and pick a clearer channel, and some do it automatically.
  7. Choose the right extension for the situation.Mesh system: best, seamless, most expensive. Powerline adapters: good where walls are the problem and wiring allows. A basic extender: cheapest, halves throughput, and creates a second network name.
  8. Run a cable if you can.Unglamorous and unbeatable. For a fixed device — a desk, a television, a games console — an ethernet cable removes the problem permanently.

Tips

  • Wifi speed and broadband speed are different things. Upgrading the package does nothing for a room the signal barely reaches.
  • A mesh node placed halfway between the router and the bad room works far better than one placed in the bad room, where it only receives a weak signal to rebroadcast.
  • Test at different times. If it is only slow in the evening, that is congestion rather than coverage.

Questions people ask

Will a faster broadband package fix a slow room?

No, if the speed is fine next to the router. That is a coverage problem inside the house and needs mesh, powerline or a cable.

Should I use 2.4GHz or 5GHz for a distant room?

2.4GHz. It is slower at its best but travels much further through walls, and a usable slow signal beats an unusable fast one.

Written and maintained by the GuideHQ editorial team. More in Technology.