The most frequent question from clients building a residential BMS: "why would I pay for KNX when Home Assistant on a Raspberry Pi for 80 EUR can do the same?" Short answer: it can't. Medium answer: it can do 90% of the functionality, but on an entirely different TCO profile — not acquisition price, but operating responsibility over a 10–15 year horizon. This article compares three real quotes for the same villa, including hidden costs that occasionally get left out.
Starting point — 200 m² villa, Bratislava, new build
Client: 4-person family, planned new build, layout:
- Ground floor: living room 45 m², kitchen 22 m², dining 18 m², hallway, WC, technical room (boiler + plant)
- 1st floor: 3× bedroom, 2× bathroom, walk-in closet, study 14 m²
- Garage with utility connection, terrace 60 m²
Planned smart functions: - Lights: 38 lighting circuits, 12 dimmers, 8 RGB-W zones, scenes (Goodnight, Movie, Morning, Holiday) - Blinds: 14 electric blinds, automation by sun position + weather - Thermal control: zoned underfloor heating (8 zones), 3× split AC (3 zones), Daikin Altherma heat pump 9 kW + 300 l DHW tank - Security: alarm (Jablotron), cameras (Hikvision 6× IP), security doors with biometrics - Network: WiFi mesh (Unifi 3× AP), gigabit Ethernet in every room - Audio/video: distributed audio in 6 zones (Sonos or KEF), 2× TV - PV + battery: planned 8 kWp PV + 10 kWh battery + EV charger
Quote A — KNX (38,000 EUR)
Supplier: certified KNX integrator with 15 years' experience. Breakdown:
- KNX devices: 142 pcs (switches, dimmers, actuators, sensors, blind gateways, KNX-Modbus gateways for the heat pump)
- - Switches: 24× MDT BE-GT2TS @ 95 EUR = 2,280 EUR
- - Dimmers: 12× ABB DA-S 4.16.1M @ 280 EUR = 3,360 EUR
- - Lighting actuators: 6× Gira 2106 03 @ 240 EUR = 1,440 EUR
- - Blind actuators: 4× MDT JAL-0810D.02 @ 420 EUR = 1,680 EUR
- - RGB-W actuators: 2× MDT AKD-0424V.02 @ 380 EUR = 760 EUR
- - Motion + brightness sensors: 8× Gira 5300 02 @ 165 EUR = 1,320 EUR
- - Temperature sensors + thermostats: 8× MDT SCN-RT8AP.01 @ 145 EUR = 1,160 EUR
- - Multi-function modules (weather, IP gateway, etc.): 980 EUR
- - Devices total: 12,980 EUR
- Installation + KNX cabling: 800 m KNX TP1 cable @ 1.80 EUR/m + terminals + boxes = 2,100 EUR + electrician labour 80 h @ 35 EUR = 4,900 EUR
- ETS6 design + parameterisation: 65 hours @ 75 EUR = 4,875 EUR
- Visualisation (Gira X1 or MDT VC.01): HW 1,800 EUR + design 20 h @ 75 EUR = 3,300 EUR
- HP + HVAC integration via KNX-Modbus gateway: 1,200 EUR HW + 8 h design = 1,800 EUR
- Audio integration (KNX-IP gateway to Sonos): 850 EUR
- Alarm + camera integration via KNX: 1,400 EUR
- Commissioning + handover + documentation: 1,600 EUR
- Warranty (5 years full, 25 years spare parts) + 1 year free support: included
Total: ~31,700 EUR + 20% VAT = 38,040 EUR
KNX upsides
- Longevity: KNX from 2026 will communicate with KNX from 2046. No firmware updates required, no EOL (end-of-life) devices.
- Multi-vendor: ABB, Gira, Jung, MDT, Siemens, Berker, Theben — all interoperable. If the Gira X1 visualisation ages out in 8 years, you swap it for a Jung Smart Visu Server without rewriting the configuration.
- No cloud: KNX runs 100% locally. Cloud connection (remote access, integration with Alexa/Google) goes through optional gateways (Gira S1, MDT KSC-1).
- Resale value: a villa with KNX in 2026 has a market price 8–15% higher than an equivalent villa with a proprietary smart home.
- Maintenance: the ETS6 project is handed over to the client (export ZIP file). Any KNX integrator in Europe can open the project and make a change.
KNX downsides
- CAPEX: 1.8–2.2× more expensive than Loxone, 4–4.5× more expensive than Home Assistant DIY.
- Configuration complexity: ETS6 isn't user-friendly. The client can't "just add a switch" — it requires an integrator.
- Updates for new features: the KNX standard expands slowly. Some modern scenarios (AI-based predictive heating, energy management with PV) require extra devices or gateways.
Quote B — Loxone (21,000 EUR)
Supplier: Loxone certified partner. Breakdown:
- Loxone Miniserver + extensions: main controller + 4× extension (inputs/outputs/DALI/AC) = 3,850 EUR
- Loxone Tree or Air devices: 95 pcs
- - Touch switches: 18× Loxone Touch @ 145 EUR = 2,610 EUR
- - Lighting actuators (relay extension built-in): included in extension
- - Dimmers: 12× via DALI extension @ 38 EUR (DALI ballasts) = 456 EUR
- - Blind actuators: via extension and Tree relay = 920 EUR
- - Motion/brightness sensors: 8× Loxone Motion Sensor @ 195 EUR = 1,560 EUR
- - Temperature sensors: 8× Loxone Room Comfort Sensor @ 220 EUR = 1,760 EUR
- - Counters + other: 850 EUR
- - Loxone HW total: 8,156 EUR
- Installation (Loxone Tree topology over Cat6 cable): 600 m Cat6 + labour = 2,800 EUR
- Loxone Config design: 35 hours @ 70 EUR = 2,450 EUR
- Loxone App + Visu: free (included with the Miniserver)
- HP + HVAC integration (Modbus via Modbus Extension): 480 EUR + 6 h = 900 EUR
- Audio (Loxone Music Server or Sonos integration): 750 EUR
- Alarm + camera (Loxone Intercom + 3rd party via REST API): 1,200 EUR
- Commissioning + handover: 800 EUR
- Warranty 2 years full, 5 years spare parts
Total: ~17,906 EUR + 20% VAT = 21,487 EUR
Loxone upsides
- Price: 45–50% cheaper than KNX with ~85% of the functionality retained.
- Loxone Config: far more user-friendly than ETS6. An integrator needs 20–40 hours of training (vs. 6 months for ETS6).
- Complex functions out-of-the-box: Loxone has built-in scenarios (Wake-up, Goodnight, Holiday mode, Presence simulation) — in KNX the integrator has to program them.
- Cloud + remote app: Loxone Cloud service is free. Available over the internet without a VPN.
- Active development: Loxone ships 2–3 major firmware updates per year, adding new features.
Loxone downsides
- Vendor lock-in: Loxone Miniserver = the only controller. Loxone Tree devices = only with Loxone. If Loxone disappears (or moves to less favourable licensing), the client has a smartware brick.
- Cloud dependency: some features (remote app, push notifications) require the Loxone Cloud server in the EU. If the service goes down, local operation runs, but remote access doesn't.
- Resale value: a villa with Loxone has the same or a lower price than a villa with KNX (due to vendor risk).
- Hardware lifecycle: Loxone Miniserver generation 1 (2009) → 2 (2014) → 3 (2020). At each generation, part of the older devices becomes sub-optimal. Real lifespan of the complete system: 12–18 years (vs. 25+ for KNX).
- API: Loxone has a REST API, but it's not as open as KNX. Third-party integrations (smart appliances, custom IoT) are limited.
Quote C — Home Assistant DIY + integrator setup (9,500 EUR)
Supplier: tech-savvy client (or semi-DIY integrator). Breakdown:
- Home Assistant Yellow (official HA hardware, 8 GB RAM, M.2 SSD) or HA on Raspberry Pi 5 + Home Assistant Green: 200–550 EUR
- Zigbee dongle (SMLIGHT SLZB-06, Sonoff ZBDongle-E): 35 EUR
- Z-Wave dongle (Zooz 800 Series Z-Wave): 45 EUR
- Devices (Zigbee + WiFi mix):
- - Shelly switches (WiFi): 38× Shelly Plus 2PM or Shelly Pro 4PM @ 28 EUR (per circuit) = 1,064 EUR
- - Dimmers Shelly Dimmer 2 or Wago/Eltako KNX-RF: 12× @ 45 EUR = 540 EUR
- - Blind motors + Shelly 2PM: 14× @ 95 EUR = 1,330 EUR
- - RGB-W: 8× Shelly RGBW2 or WLED ESP32 controllers @ 22 EUR = 176 EUR
- - Motion/temperature sensors: Aqara FP2 @ 75 EUR × 4 = 300 EUR, Aqara Temp Humidity @ 18 EUR × 8 = 144 EUR
- - HVAC integration: Daikin Altherma has cloud API (BRP069A62) + local MELCloud-style; or via Modbus and a USB-RS485 dongle = 280 EUR
- - Sonos: native HA integration is free
- - HW devices total: ~3,700 EUR
- Network infrastructure: Unifi Dream Machine Pro + 3× U6-Pro AP + UniFi switch = 2,400 EUR (this would be bought with KNX/Loxone too)
- Installation (electrician for Shelly retrofit, cable structuring): 280 EUR/day × 4 days = 1,120 EUR
- HA configuration (YAML + automations + dashboards): 60 hours @ 35 EUR (junior integrator or DIY client's hourly value) = 2,100 EUR
- NABU CASA cloud subscription (official HA cloud for Alexa/Google + remote access): 75 EUR/year
- Warranty: per-device per manufacturer (2 years Shelly, 2 years Aqara). No integration warranty.
Total: ~9,500 EUR (including network infrastructure that would be bought in every variant)
Home Assistant upsides
- Price: 70% cheaper than KNX, 55% cheaper than Loxone.
- Open-source: no vendor lock-in. Community of 250,000+ developers, 2,500+ integrations.
- Flexibility: Home Assistant integrates 90% of everything on the market (Tesla, Powerwall, EV chargers, smart appliances, calendar, weather, Slack, Discord…).
- Updates: HA Core ships a new release every month. New features, new integrations land daily.
- AI-friendly: HA + LLM (local Ollama, Google Gemini, Anthropic Claude) via the Assist Pipeline → AI-driven scenarios.
Home Assistant downsides
- Maintenance burden: an HA Core update can break an integration. The client has to check release notes every month and sometimes fix broken automations. Without technical skill the client won't manage on their own.
- Reliability: the HA server runs on one physical box. If the HA machine fails → the entire smart home is offline. Solution: HA backup + redundant hardware (a second Raspberry Pi as a hot-spare), which increases complexity.
- Security: HA has historically had many CVEs (CVE-2024-32018, CVE-2024-29402…). A client without an active security-update culture is exposed.
- Integrator support: Slovakia has 5–8 HA-experienced integrators. If the main integrator fails, you're either DIY or on the community forum.
- Resale value: an HA-based smart home does not raise the villa's market price. Some buyers see it as a "DIY hobby," not a professional BMS.
- Long-term maintenance complexity: a 12-year-old HA install will need migration to new hardware + Python version + possibly breaking changes in integrations. With KNX/Loxone this doesn't exist.
Trade-off matrix
| Factor | KNX | Loxone | Home Assistant |
|---|---|---|---|
| CAPEX (200 m² villa) | 38,000 EUR | 21,000 EUR | 9,500 EUR |
| Hardware lifespan | 25+ years | 12–18 years | 8–12 years (components) |
| Vendor risk | Low (multi-vendor) | High (Loxone) | Medium (per component) |
| Maintenance burden on client | None | Low | High |
| Out-of-box functionality | 85% | 95% | 99% (with configuration) |
| Flexibility / API | Medium | Medium | High |
| Resale value impact | +8–15% | +0–5% | 0% |
| Integrator availability SR | High | Medium | Low |
| Cloud dependency | Optional | Yes (default) | Optional |
| TCO 15 years (incl. updates) | 42,000 EUR | 28,000 EUR | 16,000 EUR (DIY) or 28,000 EUR (with integrator) |
When which
KNX is the right choice if
- Property value > 1.5M EUR — the +8–15% resale value impact is worth the extra 17,000 EUR CAPEX.
- Living plan > 20 years — KNX outlives 2 generations of other systems.
- The client doesn't want a maintenance burden — wants to hand it off to an integrator.
- Multi-vendor flexibility matters — wants the option to swap devices without rewiring.
- No cloud dependency — privacy paranoia, GDPR-strict.
Loxone is the right choice if
- Property value 500k–1.5M EUR — the sweet spot of CAPEX vs. functionality.
- Living plan 10–20 years — Loxone hardware will outlive it.
- The client wants an out-of-box smart home — without reading YAML configs.
- The client accepts vendor lock-in — trusts Loxone will still exist in 15 years.
- Loxone partner in the region — has regular contact with the integrator.
Home Assistant is the right choice if
- The client is tech-savvy — Linux, YAML, Python don't surprise them.
- Property value < 500k EUR — extra CAPEX on KNX/Loxone isn't justified.
- Living plan 5–15 years or rental.
- Maximise flexibility, integrate non-standard devices (EV, calendar, AI, 3rd party API).
- The client accepts the maintenance burden — wants to look after it themselves.
Hybrid scenarios
In practice we run into hybrid setups:
- KNX core + HA visualisation layer: KNX for lights/blinds/HVAC (the spine), HA for dashboards, AI integration, EV charging, weather, calendar. Best of both, but more complex on failure.
- Loxone core + HA for smart appliances: Loxone Miniserver for the base, HA via REST API for integrations that Loxone doesn't cover (e.g. an older Bosch fridge).
- HA + Shelly + KNX accent: residence primarily on HA, but critical zones (kitchen, living room — where switching happens most) on KNX switches for longer life.
Our default recommendations
- Villa > 1.2M EUR, plan 20+ years, delegator client: KNX. The investment is recouped in resale value + zero maintenance burden.
- Family house 400k–800k EUR, mid-savvy client, plan 12–18 years: Loxone. The boring-correct choice.
- Family house < 400k EUR, tech-savvy client, or rental property: Home Assistant + Shelly. Cheap, flexible.
- Commercial property (offices, hotels): KNX or BACnet depending on size. Home Assistant isn't suitable for a commercial BMS.
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*We design and implement BMS for residential and commercial projects. The first consultation call (45 minutes) walks through the layout, living plan, client's technical skill — the output is a system recommendation + price indication with 3 variants. Sometimes we recommend not investing in a BMS at all, if the layout is too small or the living horizon is short.*