Smart Lighting: Dimmer or Switch?

Not all smart lighting is built the same. In this article, we explore the differences between two Fibaro in-wall modules: The Dimmer 2 and the Double Switch 2. This might seem like a trivial comparison at first – surely the product names give it away? Well … yes, but only to a certain extent. Read on for a more detailed breakdown.

Both products have the same dimensions and easily fit behind any normal light switch in your home. Installed between your switch and the light fitting, they allow you to control the lights in a number of ways. Automatically (based on time of day or a motion sensor), or manually using either a smartphone app or using the existing switch as normal. This is a crucial point of difference compared to other “smart light” systems such as Philips Hue: You retain the use of your regular switch. (Think about it – how smart is a smart bulb when you turn off the power?)


A key difference between the two modules is that the Double Switch allows you to control two separate lighting circuits. The Dimmer can only control a single circuit but, allows you to dim the lights either from the switch, your phone, or automatically.


The Dimmer does not require neutral at the switch. This means that in a 2-wire system where your circuit is looped at the lights, you can still control it without any additional wiring. This makes the Dimmer very suitable for retrofit applications. Even if you don’t need the dimming function and only use it as a switch. It achieves this by drawing a very small standby current, even when the switch is off. The “downside” to this is only seen in very low power applications i.e. very few/very low wattage LED lights or CFLs.  In these situations, the lights may flicker due to the standby current. If this is a problem, an inexpensive bypass module may be fitted.

The Switch can also be used as a relay for other loads. Think bathroom lights + underfloor heating: Use one output to control the lights, and the other to automate the underfloor heating with settings from the controller or your smartphone. Or bathroom lights + fan: Automatically turn on the fan when the lights have been on for 5 minutes, and leave the fan on for 10 minutes after the lights go out. These are simple suggestions, the opportunities are really only limited by your imagination. (And the load rating of the switch!)

Do you have any experience or questions you want to share? Let us know!

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