Now that we know what smart relays are and how they work, it's time to make the big purchase. Opening the online stores, you will find that there are two completely different paths to make your lights "smart":
Which is the correct choice? As engineers, the answer we give is not only technical, but mainly practical and aesthetic. Let's put the two solutions under the microscope to save you time, money and... moaning about the appearance of your wall.
We remind you that these are the small "boxes" (eg Shelly Plus 1, Sonoff Mini) that go inside the wall and the old switch is connected to them.
The Disadvantage (The "Kleistophobia" of the wall): As we pointed out, the biggest problem is space. Cramming a relay, the old switch mechanism and 5-6 hard 1.5mm² wires into a shallow 40mm round box is often a nerve-wracking nightmare for any electrician.
This is their biggest asset. If you have beautiful, classic switches at home (eg Legrand, Vimar or Jung series) and want to keep the same aesthetic everywhere, relays are the way to go. The house is becoming smart, but no one understands it visually.
In Greece, we often have a single plastic frame that houses 3 things together: Light Switch + TV Socket + Power Socket. The hidden relay is inserted from the back without spoiling this single unit.
If the Wi-Fi board breaks, in many models you can easily rewire the switch, while your switch never stops having that classic "mechanical" clack feel.
Here you throw the old switch in the trash (along with its plastic cover) and replace it with a single, "high-tech" device.
The Downside (The Incompatibility Nightmare): Smart Switches have their own, unitary frames (usually glass). They do not snap together with the frames of the other switches. If you have a switch and an outlet side by side on the same wall, and you only change the switch, you will create a "Frankenstein" aesthetic (a glass square next to an old, yellowed plastic).
Because all the "smarts" (the board) are built into the body of the switch, their backs are usually very flat. They fit comfortably even in the shallowest, old wall boxes. Unscrew the old one, screw in the new one. End.
Many of them (especially in Zigbee protocol, like Aqara's) are built from scratch to work without a neutral, so you are not looking for special relays and bypasses.
They have discreet lights that show you in the dark where the button is, giving a strongly futuristic feel to the room.
If the criterion is strictly financial, things are clear:
They usually cost €15 - €20 each. As long as you keep your old plastics, it's the cheapest solution per lighting line.
A quality smart switch starts at €30 and can reach €50. It makes sense, as you pay not only for the software, but also for the crystal/plastic of the finish.
Are you confused? Follow this simple selection "algorithm":
1. Do you have multiple panels (switches and outlets joined in the same lid)? YES: You must go to Smart Relays (Micro-Modules). It is the only way not to damage the aesthetics of the wall. NO: (The switch is on its own on the wall). Continue to the next question. 2. Are the boxes inside your wall deep (over 45mm) or shallow/narrow? Deep: Put Smart Relays. It will work out cheaper and you will keep the classic feeling on the press. Shallow / Narrow: Select Smart Switches. You will save hours of frustration and the risk of short circuit from tangled cables.
There is no "wrong" technology here. Both systems are now extremely mature and reliable (especially if you choose branded companies). The decision is 50% a matter of electrical space (what your wall allows) and 50% a matter of taste (whether you prefer the classic plastic "clunk" or the modern glass "touch").
Next Step: You've chosen your gear and you're hitting the runway. However, there is a lamp that turns on at one end of the corridor and goes off at the other. This is the famous "Alle-Retour" circuit, the absolute headache of novice DIYers!
We continue to the next technical guide: Smart Switches Alle-Retour (Two-way Switching): How to make the correct wiring in stairs, corridors and bedrooms.
Return to category.
Go to categoryReturn to the central guide.
Go to guide
