The short answer
Powerline works brilliantly in some houses and poorly in others, and you cannot tell which without trying. The rule that matters: both adapters must be on the same electrical circuit and plugged directly into the wall, never into an extension lead.
Powerline adapters send network data over your mains wiring. Where the wiring cooperates, they deliver a wired-quality connection to a room no cable reaches. Where it does not, they underperform badly — and the difference is your house, not the product.
What decides whether it works
- Same circuit. Data crossing between circuits at the consumer unit loses a great deal of speed, and sometimes fails entirely.
- Direct into the wall. Extension leads and surge protectors filter exactly the frequencies powerline uses. This single mistake accounts for most disappointing results.
- Wiring age and quality. Older wiring, long runs and multiple junction boxes all attenuate the signal.
- Electrical noise. Motors, chargers, LED drivers and dimmer switches all inject interference. A washing machine on the same circuit can visibly drop throughput while it runs.
Expect real-world speeds well below the numbers on the box, which are theoretical combined figures. A 1000 Mbps rated pair might deliver 100 to 300 Mbps in a good house, and considerably less in a poor one.
Getting the best out of them
Plug both directly into wall sockets
Never into an extension lead, surge protector or multi-plug. If the adapter has a passthrough socket, use that for whatever you displaced.
Pair them close together first
Plug both into sockets in the same room, press the pairing buttons, and confirm they link. Then move one to its final position. This separates a pairing problem from a wiring problem.
Try several sockets in the destination room
Throughput can vary substantially between sockets a few metres apart, depending on which circuit they belong to. Test two or three before settling.
Keep them away from noisy appliances
Fridges, washing machines, chargers and dimmer circuits all degrade the signal. Avoid sockets shared with them where you can.
Measure the result
Run a speed test on a device wired to the far adapter. Compare with what the same device gets on Wi-Fi in that room. If powerline is not clearly better, return them — that is the only real test.
Powerline performance is unpredictable enough that you should treat the purchase as a trial. Reputable retailers accept returns, and there is no way to know in advance how your particular wiring behaves.
Powerline versus the alternatives
- Versus a Wi-Fi extender: powerline usually wins, because the backhaul travels over wiring rather than competing for airtime.
- Versus mesh: mesh is more convenient and covers a whole house; powerline is cheaper and better for one distant fixed device such as a console or a desktop.
- Versus real Ethernet: a cable wins every time. If you can run one, run one.
Frequently asked questions
Do powerline adapters work in old houses?
Sometimes very well and sometimes poorly. Age matters less than whether the two sockets share a circuit and how much electrical noise is present. It is genuinely worth testing rather than predicting.
Why is my powerline speed so much lower than advertised?
The headline figure is a theoretical combined maximum. Real throughput is typically a fraction of it, and falls further across circuits or with interference. That is normal rather than faulty.
Can I use powerline adapters in a flat or apartment?
Yes, and they often work well because distances are short. Use the encryption pairing feature, since your wiring may be shared with neighbours.
Do they work between floors?
Usually, provided both sockets are on the same circuit. Crossing between circuits at the consumer unit is what causes the biggest losses, not vertical distance.
Plug them straight into the wall and test properly. If the numbers do not beat Wi-Fi in that room, send them back.
