In the smart home industry there are two philosophies. One builds on wires, the other on radio. Both work. Both have their target audience. But the two are not interchangeable — the choice of the first protocol decides who will service your house in 15 years.
Wired (KNX, DALI, Modbus) — for residences and 15+ years
KNX has existed since 1990. It is a wired protocol, IEC 14543-3, supported by 500+ manufacturers. Installation requires separate KNX cabling (low-voltage twisted pair) running alongside power. Configuration via ETS software.
**Pros:** - Lifespan 25+ years. KNX from 2000 works with KNX from 2026 without changes. - No single point of failure. Decentralized — every component decides for itself. - No network outages. Physical wire = signal. - Multi-vendor. If manufacturer A fails, you use a component from manufacturer B.
**Cons:** - In-wall installation = for new builds or major renovations. Retrofit is expensive. - Components expensive (KNX switch €80–150, WiFi switch €20–40). - ETS software + KNX engineer needed. Without them, it's not a home project.
**Where it makes sense:** new builds with the plan "I want to stay here 20+ years", major renovations. Commercial buildings (offices, hotels) almost always.
Wireless (Zigbee, Z-Wave, Matter, WiFi) — for rentals and 5–7 years
Wireless protocols run on radio (Zigbee 2.4 GHz, Z-Wave 868 MHz, WiFi 2.4/5 GHz). No wires, no construction work. You install components yourself, pair via hub or router.
**Pros:** - Retrofit = easy. You replace a WiFi switch for an old one in 10 minutes. - Components cheap (€10–40). - DIY-friendly. Home Assistant and similar support hundreds of manufacturers.
**Cons:** - Lifespan 5–7 years. Zigbee 1.x → 3.x, Z-Wave 700 → 800 — compatibility broke at every iteration. - Battery-powered components (switches, sensors) need battery replacement every 1–3 years. - Radio interference. WiFi in the 2.4 GHz spectrum competes with Zigbee, Bluetooth, microwave. - Hub = single point of failure. Hub goes down = whole system is offline.
**Where it makes sense:** rental apartments (can't go into the wall), temporary solutions, a client who wants to experiment before a full investment.
Hybrid: Loxone, Jung, Gira
Some systems support both philosophies. Loxone has wired and wireless variants. Gira and Jung have KNX and WLAN-only systems.
This is the right choice for residences where: - Power electrical installation goes into the wall (always) - Control electrical installation goes into the wall (KNX) - Sensors and switches can go wireless after the craftsman work is finished
The client gets a "spine" of KNX (lights, blinds, HVAC) + retrofit flexibility (sensors, inputs, scenes) via wireless.
Decision table
| Question | Wired | Wireless | |----------|-------|----------| | New build or major renovation? | Yes | Caution (unnecessary complexity) | | Plan to stay in the house > 10 years? | Yes | Caution | | Commercial building? | Yes | No | | Rental or temporary solution? | No | Yes | | DIY-friendly, no KNX engineer available? | No | Yes | | Maximum lifespan > 15 years? | Yes | No | | Tight budget? | No | Yes |
Anti-pattern: "let's go WiFi, later we'll swap for KNX"
This never happens. After installing a WiFi system, the house is "smart" and the KNX investment requires ripping out walls. The client then lives another 15 years with a wireless system that no longer fits them.
If the business case assumption is "I'll do it properly later", do it properly now. The difference between WiFi-then-KNX vs. KNX-from-start = 2–3 months payback on a new build.
Conclusion
KNX isn't "better" than WiFi. They are two technologies for two different situations. The choice is in lifespan, not in price.
- If you plan to live in the house 15+ years → wired.
- If it's a rental or experiment → wireless.
- If it's a new build and you can be patient during installation → hybrid systems like Loxone.
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*We apply this framework to every smart home inquiry. We'll walk through the specific use case (layout, budget, time horizon) on a 30-minute call — sometimes we recommend not investing at all if the layout is too constrained.*