What is a mesh network, and how is it different from a Wi-Fi extender?
Both push Wi-Fi further into a building, and they do it by fundamentally different mechanisms — which is why one usually works well and the other frequently disappoints.
What an extender does. It receives the router's signal and rebroadcasts it. In the simplest and cheapest designs it does this on the same radio at the same time, which means every packet is transmitted twice — halving throughput for everything behind it. It also typically creates a separate network name, so devices cling to the weak original signal rather than switching, producing the familiar experience of standing next to the extender with one bar.
What a mesh system does differently:
A dedicated backhaul. Mesh nodes reserve a radio — commonly a 5GHz or 6GHz band, or an Ethernet cable where one exists — purely for node-to-node traffic. Client devices talk on a different radio. The halving does not happen.
One network name, with nodes cooperating to decide which should serve a given device.
Steering, using standard roaming mechanisms to nudge a device onto a better node as you move — the thing that makes walking around a house with a video call actually work.
Self-organisation, so nodes route around each other and a new node joins without manual configuration.
Central management, where the whole system updates and is configured as one device.
Where the nuance is:
A wired backhaul beats everything. Mesh nodes connected by Ethernet — or by a decent powerline or coaxial link — outperform wireless mesh substantially. If you can run one cable, run it.
Mesh still needs placement. Nodes too far apart give a weak backhaul, and every node then shares that weak link. Roughly halfway between the router and the dead zone, not in the dead zone.
More nodes is not better. Each wireless hop adds latency and reduces throughput; two well-placed nodes beat four badly placed ones.
A single better router sometimes solves it outright, and is worth trying first in a small or open-plan home.
Modern extenders have improved — dual-band models with a dedicated backhaul and a shared network name are essentially two-node mesh systems.