The honest pre-build checklist for self-builders who want a properly wired smart home. Lock these decisions in before the architect breaks ground — and save yourself five-figure retrofits.
Configure My KNX CabinetIf you are building a house in 2026 and even thinking about smart-home, the question is no longer whether — it is how, and more importantly when. The most expensive mistakes in residential automation are always made in the same narrow window: after the architect's first draft, before the electrical engineer is briefed. In those few weeks, you make decisions that either save 5,000 EUR or cost 50,000 EUR in lost comfort.
This checklist is distilled from 200+ self-build projects we have shipped cabinets into. We build the KNX switchgear after the planning is done, which means we see every mistake that was made upstream. The 12 steps below cover the ones that actually move the needle. It is the English summary of our German Bauherren-Checkliste — same structure, slightly compressed, calibrated for readers building in any EU country.
Each of the 12 steps below is tagged with one of these four phases. Get them in the right order and the rest follows:
| Phase | When | What happens |
|---|---|---|
| 1 — Concept | 9-12 months before ground-break | Define needs, choose system, set budget |
| 2 — Design | 4-9 months before | Architect + electrical engineer plan in detail |
| 3 — Tender | 2-4 months before | Split cabinet from electrician scope, file grants |
| 4 — Build | Shell + fit-out phases | Pull cable, deliver cabinet, commission |
Before reading a single product brochure, sit down with your partner or family and write out, in plain language, what you want the house to do. "Lights on the kitchen island dim from a wall panel." "Bedroom blinds close automatically at sunset." "Heating per room with a schedule." "Front door camera in the hallway." Be concrete — vague wishes ("smart heating") survive contact with the electrician less well than specific ones ("each radiator individually controlled with a weekly schedule").
Sort the list into three columns: must-have, should-have, nice-to-have. This list is the input for every subsequent decision. Without it, the architect designs for an imaginary smart-home and the electrician fills in the gaps with the cheapest components on the shelf.
For a new build with a 15+ year horizon, KNX is the right answer in roughly 80% of cases: it is an open standard (ISO 14543-3), it has 35 years of backward compatibility, and 500+ manufacturers compete for your business. Loxone is cheaper and faster to commission but proprietary — one vendor, one ecosystem. Homematic IP only makes sense for retrofit or very small homes. Conventional wiring fits only the truly minimal-budget build with no smart-home ambitions.
Detailed comparison: KNX vs Loxone vs Homematic.
Rule of thumb: smart-home should take 2 to 5 percent of total construction cost. For a 500,000 EUR single-family home, that is 10,000 to 25,000 EUR — covering switchgear cabinet, control panels, bus cable and commissioning labour. Below 2% you will compromise; above 5% you are buying things you do not need.
Two reference numbers will get you to 95% accuracy: our online configurator for the cabinet fixed price, plus a quote from your local electrician for the on-site installation work. These two figures together tell you almost the entire smart-home cost.
The KNX bus is a green twisted-pair (KNX TP, J-Y(St)Y 2x2x0.8) that runs alongside the 230 V wiring to every switch, every motion sensor, every thermostat. Per residential floor, one bus line is usually enough; one line can handle 64 devices. In parallel, pull empty conduit (M25 or M32) to every room — for CAT 7 today, fibre tomorrow, whatever standard comes next in 10 years.
If this is missed at the design stage and you have to retrofit cable later, expect 4,000 to 15,000 EUR per floor in chasing, plastering and repainting. The cable itself costs about 50 cents per metre. Pulling it now is a rounding error.
The KNX cabinet needs about 1.2 to 2.0 m² of wall space, centrally located in the house, dry, and ideally outside the living areas. Typical homes for it: utility room, technical room, dry basement, attached garage. Avoid bathrooms (humidity), avoid south-facing walls (heat), avoid bedrooms (low-frequency fan noise from active components).
The room also needs: a 230 V mains feed close by, at least one Cat 7 drop (cabinet talks IP to your visualisation server), cooling consideration (no direct heating against the back of the cabinet), and physical access for the electrician with a step-ladder. More detail in our cabinet planning guide (German).
Buy a cabinet at least 25 to 30 percent larger than your initial calculation suggests. Every project we have shipped to has added at least one feature during construction — a circuit for the new EV charger, a separate dimming output for the kitchen island that was not in the plan, an additional heating zone after the underfloor heating was redesigned. A cabinet without spare DIN rail slots cannot absorb these changes without being replaced.
The cost differential between a "just-enough" cabinet and a "comfortably oversized" one is typically 200 to 500 EUR — trivial against the cost of replacing it later. Aim for at least 4 free DIN-rail slots on delivery day.
Sit down with a floor plan and, for every room individually, decide: how many lighting circuits (ceiling + wall + spots count separately), which are dimmable, which blinds/shutters, individual room heating control yes/no, presence sensor, window contacts, panel or just push-buttons.
Our configurator walks you through exactly this logic and produces a fixed price as a side effect. If you bring the printout to the electrician's meeting, you have just reduced 4 hours of back-and-forth to 30 minutes. See also our per-room cost breakdown (German).
Where does the main touch panel hang? Hallway, living room, kitchen? At what height (typically 1.40 to 1.50 m to centre)? Which model — Gira G1, Busch ComfortPanel, MDT Smart 55, or a wall-mounted tablet? In parallel, decide on push-button stations per room — capacitive 55 mm modules in the higher-end rooms, simpler buttons in utility spaces.
This decision impacts architecture: wall recesses, mains feeds and network drops all need to be in the right place. Get it wrong and you are left with a beautiful 7" panel mounted next to a Cat 7 cable hanging out of the wall. Reference: KNX visualisation comparison (German).
Which heat source (heat pump, gas boiler, district heat)? Does it have a published interface for KNX integration (Modbus, EEBus, or a native KNX gateway)? Photovoltaic with self-consumption optimisation? Wallbox for the EV? Battery storage?
Wiring these together is the single biggest operating-cost lever in a modern home — savings of 15 to 25% on heating bills are routine when room-by-room control, weather forecast, and presence detection are coordinated. More detail: KNX heating optimisation (German).
Most self-builders give the entire KNX installation to the electrician and pay a 15 to 35% markup for it. Many electrical contractors are excellent at pulling cable and terminating mains but use a sub-contractor for cabinet assembly and ETS programming — and pass that sub-contractor's margin on to you with their own margin on top.
Smarter approach: tender the cabinet separately. You get a pre-programmed, factory-tested cabinet at a fixed price. Your electrician then only does the wiring and the final on-site commissioning. This is what we do for hundreds of self-builders a year. See: commissioning KNX sub-contractors (German).
EU national grant programmes for energy-efficient new construction (KfW in Germany, EcoBonus / Superbonus variants in Italy, MaPrimeRenov in France, regional pots in Austria and Switzerland) all share one rule: applications must be filed before any work is awarded. File late and you forfeit the grant — frequently a five-figure sum.
An energy consultant is usually mandatory for these programmes anyway, and their fee (typically 1,500 to 2,500 EUR) is often subsidised at 50% or more. The smart-home component is rarely directly funded, but smart heating control often qualifies under the broader heating-efficiency category.
During shell construction the electrician pulls the bus cable alongside the 230 V wiring, prepares the cabinet wall (mounting holes, mains feed, network drop), and runs the reserve conduits to rooms where you might want to expand later. Before plastering closes everything in, photograph every cable run with a wide-angle phone shot. These photos save hours of fault-finding 5 years later when something inevitably needs touching.
Once the cabinet arrives (typical lead time 2 to 3 weeks from us), your electrician hangs it, terminates the bus, and a KNX-certified technician runs the ETS commissioning on site — half a day to one day for a typical single-family house. At handover you receive: ETS project file, paper + digital wiring documentation, app credentials, and a walk-through of the visualisation. Put these in a labelled folder. You will need them.
The room-by-room functional plan is the single most time-consuming step. Our online configurator walks through it visually and produces a fixed-price cabinet quote at the end — typically 5 minutes per project.
Open Configurator Free ConsultationUI is German, icon-driven. We respond to enquiries in English within one business day.
"We will figure out the smart bits during fit-out." This thinking costs 4,000 to 15,000 EUR in retrofit cable runs and 2 to 3 weeks of rebuild time. The smart-home concept belongs in the architectural design phase, not the finishing phase.
Two sockets per room is a 1980s standard. In a modern home with smart speakers, robot vacuum docks, phone chargers, work-from-home stations and battery backups for various devices, plan 4 to 6 sockets per habitable room, 6 to 8 in the kitchen. Plus one empty conduit per room for future low-voltage cabling.
Comfortable, but typically 15 to 35% more expensive than splitting the scope. See step 10 above.
Garden, terrace, carport, driveway — these are forgotten in roughly 70% of first-build smart-home plans. Yet they offer the biggest comfort-per-euro improvements: scene-based facade lighting, motion-sensor driveway, intercom integration, smart letterbox. Pull bus cable to the front door and the garage at minimum.
Applications must be filed before construction starts. Miss this and you forfeit 5,000 to 25,000 EUR. See step 11.
| Months before ground-break | Decision | Who is involved |
|---|---|---|
| 9-12 | Functional needs, system choice, budget envelope | You + family |
| 6-9 | Architectural plan incorporating smart-home spec | Architect + you |
| 4-6 | Electrical engineering, cabinet specification | Electrical engineer + cabinet builder |
| 3 | Grant applications, tender packages | Energy consultant + you |
| 1-2 | Award contracts, place component orders | You |
| 0 (shell phase) | Pull bus cable, prep cabinet wall | Electrician |
| +2-4 (fit-out) | Cabinet delivery, ETS commissioning | Cabinet builder + electrician |
Walk through each room, click your functions, see the fixed cabinet price at the end. Take the result straight to your electrician's first meeting.
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