Why Is My Wi-Fi So Slow at Home? 8 Real Causes and Simple Fixes

Slow home Wi-Fi is one of our most-booked remote support tickets — and the real culprit is almost never the internet plan. Here are the eight causes we solve every week, ranked by how often we find them.

1. Router placed in the wrong spot

A router in a cupboard, behind a TV or in a corner will drop signal strength by up to 40%. Place it central, high up, and away from metal and microwaves. This single change fixes more slow-Wi-Fi tickets than any other.

2. Old 2.4 GHz-only devices dragging the network down

If an old printer or smart plug only supports 2.4 GHz, it can slow down every device on that band. Move slow devices to a dedicated 2.4 GHz guest network and keep the main network on 5 GHz or Wi-Fi 6 6 GHz.

3. Interference from neighbours' Wi-Fi

In apartments, dozens of overlapping networks can crush your throughput. Log into your router's admin page and manually set the 2.4 GHz channel to 1, 6 or 11 (whichever is least crowded). Use a free tool like WiFi Analyzer to check.

4. Firmware not updated in 2+ years

Consumer routers ship with buggy firmware. Manufacturers push updates that fix speed and security — but almost no one applies them. Check your router's admin page (usually 192.168.0.1 or 192.168.1.1) for a Firmware Update section. This is a 5-minute job.

5. Too many devices for the router's class

The £30 router your ISP shipped is rated for about 15 concurrent devices. A modern smart home easily has 30+ (phones, laptops, TVs, smart plugs, cameras, thermostats). An entry-level Wi-Fi 6 router with 5+ streams roughly doubles real-world throughput.

6. Bad Ethernet cabling to the router

A cracked or Cat-5 (not Cat-5e) cable between the ONT/modem and your router will cap your entire home at 100 Mbps regardless of the plan. Costs $5 to replace and often unlocks 3–5× the actual speed.

7. One neighbour or roommate saturating the connection

A single device downloading a game or backing up to the cloud can saturate your upload bandwidth and make every video call laggy. QoS (Quality of Service) settings on modern routers let you prioritise video calls — we set this up in most remote sessions.

8. ISP hardware genuinely failing

Rare, but real: a slowly dying ISP-supplied modem can lose 30–50% of throughput before it fully fails. If speeds are bad from a wired connection right next to the modem, call your ISP for a replacement — usually free.

Mesh vs extender vs new router

• Coverage problem in a large home → mesh Wi-Fi 6 system (Deco, eero, Nest).
• One dead room only → a good extender is fine.
• Old router (>5 years) → replace outright, don't add hardware to it.