A smart home without renovation
yes, without breaking a single wall

"The house is finished, the walls are perfect: we missed the smart home train." We hear it all the time, and until a few years ago it was true. Not any more: the retrofit — making an existing home intelligent without touching its wiring — is now a mature, discreet and surprisingly accessible technology. No chasing, no dust, no building site. And in daily use, the result is comparable to a home that was born smart.

How it works, without opening a single wall

The secret lies in three families of components, all designed to slip into the spaces your home already has.

Invisible modules behind the switches

Inside the ordinary wall boxes — the ones holding the switches you use every day — there is almost always room for a micro-actuator the size of a matchbox. It connects to the wires that already arrive there, and from that moment the light or the roller blind answers to two masters: the physical switch you've always had, which keeps working exactly as before, and the app, your voice, or the automations. From the outside, nothing shows: the plate stays yours.

Wireless controls where cables don't reach

The classic problem of homes built a few decades ago: the switch is in the wrong place, or missing altogether — beside the bed, near an entrance added later, on the "blind" side of the room. Once, that meant chasing a channel into the wall; today you simply stick a battery-powered wireless button, as slim as a switch plate, exactly where you need it. The batteries last two to three years on average, and each key can carry more than one function: a tap turns on the light, a long press lowers the blind or triggers a scene.

Battery sensors and a hub acting as director

Presence sensors, door and window contacts, temperature and air-quality sensors: they attach with adhesive pads and talk over the air. Coordinating everything is a multi-protocol hub, a small device fluent in the open standards — Matter, Zigbee, Wi-Fi, Bluetooth — that makes them all speak to each other. It is the director: it receives the signals from sensors and buttons and conducts lights, climate, blinds and scenes.

What about dated systems? They often join in too. A twenty-year-old ducted air-conditioning system the manufacturer declares "not connectable" can be brought online with a small dedicated interface; even old proprietary home automation systems, frozen a decade ago, can be hooked to the hub and made to work alongside everything else. Nothing gets thrown away: a layer of intelligence is simply added on top of what is already there.

What becomes possible

The real difference isn't voice control: it's automation. A few concrete examples, all achievable as a retrofit:

• The night courtesy light — you get up at three in the morning, the sensor understands it's dark and turns on a soft light at 5%: enough not to stumble, not enough to truly wake you.
• Climate that thinks — a window left open with the air conditioning running? First a warning, then the house switches it off by itself. The end of silent waste.
• The exit scene — one button by the door: everything switches off, the blinds come down, whatever needs arming is armed. No more final tour of the house before leaving.
• Motorised curtains and blinds — they follow the daylight, close on their own in the evening, come down when the sun beats on the sofa.
• The right air — a sensor detects CO₂ and odours and runs the ventilation or the bathroom extractor only when needed, switching them off again by itself.

The special case: holiday homes and short lets

There is one field where the retrofit is not a comfort but almost a necessity: short-let apartments. A check-in button welcomes the guest with the lights on, blinds half raised and the climate already set for the season; a check-out button switches everything off after a few seconds — without lowering the blinds, in case someone is still out on the terrace. Cleaning gets its own scene: "job done" closes the house only if every door and window reads as shut — otherwise the house, politely, asks to try again. And the owner receives a notification at every step, wherever they are. Anyone managing even a single apartment knows what these three lines are worth.

What it costs, honestly

The item that matters most is not the hardware: it's the design. Deciding carefully where actuators are needed, where a wireless button is enough and which automations make sense for the way you live avoids buying pointless devices — and makes the difference between an intelligent home and a drawer full of gadgets.

The honest limit (and when to choose the cable)

Mature wireless is reliable, but it asks for a little care: a round of batteries every two or three years, and the — rare — possibility of having to restart the hub a couple of times a year. Nothing dramatic, but it's only fair to say it. Which is why we always add one thing: if you are about to renovate, with the walls open anyway, the calculation changes and a wired system — still the benchmark for reliability — deserves serious consideration. We've dedicated a twin article to the differences between the two roads: wired or wireless smart home, which to choose.

Where to start

At Mariani we have been designing homes since 1928, and technology entered our way of working long ago: in-house integration know-how and certified installers in our portfolio for the executive side. The journey starts, as always, with a site visit — at your home or in our Milan and Arluno showrooms — to understand how your wiring is laid out, how you live your rooms and which automations would genuinely make your life simpler. Then the project, with a clear quote and no surprises.