It is nearly always the first question: wired or wireless? The short answer is that it depends on the state of your building, not on which technology is newer. The longer answer is worth reading, because this is a decision that is hard to reverse later.
# Wired: KNX and its relatives
A wired system runs a dedicated cable to every control point, and the devices talk to each other over that bus. It is separate from the power cabling and carries data only.
In its favour
- Very high reliability; radio interference and signal drop simply do not apply
- A service life measured against the building, not the gadget
- An open international standard with many manufacturers
- No batteries anywhere in the control layer
- Scales to large buildings with many points better than radio does
Against it
- Higher up-front cost, in both equipment and labour
- Only practical in a new build or a full renovation
- Adding a point after completion means pulling cable
- Demands careful planning at design stage
# Wireless: Zigbee, Z-Wave and similar
A wireless system links devices over radio into a mesh, where every mains-powered device also relays traffic for the others.
In its favour
- Installs into a finished, occupied house without breaking anything out
- Lower entry cost, and you can start small
- Adding a device later is straightforward
- Devices can be moved when the room changes
Against it
- Some devices run on batteries, and batteries get changed
- Thick concrete and structural steel cut the range
- Quality varies enormously between brands
- Shorter useful life, and a proprietary protocol can be abandoned
# Side by side
| Criterion | Wired (KNX) | Wireless (Zigbee) |
|---|---|---|
| Up-front cost | Higher | Lower |
| Disruption to install | Significant | None |
| Long-term reliability | Very high | Good |
| Extending later | Hard | Easy |
| Battery changes | None | Some devices |
| Best suited to | New build, full renovation | Existing occupied house |
# The rule of thumb I give clients
If the building is still at first fix and the wiring is going in anyway, run the bus cable now; the marginal cost at that stage is small and it keeps every option open later. If the building is finished and lived in, wireless is the sensible answer, and trying to force a wired system usually ends in expensive demolition that was never worth it.
# What matters more than the protocol
Two decisions affect your satisfaction more than wired versus wireless ever will.
First, a local controller instead of a cloud service. If the scene logic runs on a server in another country, losing the internet loses the house. And if that company shuts the service down, your equipment becomes expensive scrap.
Second, keeping the physical switch. Every light that becomes smart should still answer its wall switch. Guests, children and older relatives should not need an app to turn on a lamp, and when something breaks there has to be a manual path.
For an assessment of your building and a recommendation in Gurab Zarmikh, Soumeh Sara and the surrounding area, get in touch.
Related services
Smart home