Shelly
Shelly Dimmer Gen3
- Wi-Fi
- Matter
- Bluetooth
Verified September 2026
The go-to Wi-Fi dimmer for UK no-neutral lighting circuits — it works without a neutral wire, though you'll need the Shelly bypass for LED loads under 20W. Trailing-edge only, with power metering, fully local in HA, and slim enough at 16.5mm deep to fit almost any UK back box — unlike the Fibaro Dimmer 2, which needs a 60mm-deep pattress. At £28.99 it's roughly half the Fibaro's £53-55, trading Z-Wave's mesh range and physical scene-controller input for Wi-Fi's simpler setup and Matter support. The 200W ceiling comfortably covers a multi-bulb pendant or downlight circuit, and since dimming happens on-device, HA brightness changes land instantly with no cloud round-trip.
In Home Assistant
| Control | Type | What it does |
|---|---|---|
| Gamma correction | Config | Adjusts the dimming control signal to correct perceived brightness non-linearity; raise it if the low end of the HA brightness slider jumps too fast. |
| Warm-up impulse | Config | Brief power boost applied when commanded brightness is below 10%, needed to reliably start LED drivers that won't wake at very low duty cycle; set via the device web UI, not an HA entity. |
| Input mode | Select | Governs how the attached physical switch behaves — toggle-and-hold dimming, paired up/down buttons, or fully detached so the wired switch can drive its own HA automation independent of the dimmer's own state. |
| Minimum brightness on toggle | Number (%) | Floor brightness applied whenever a toggle-on would otherwise land below it, preventing ultra-low dim levels some LED drivers can't sustain without flicker. |
| Power/voltage/current limits | Number | Configurable trip thresholds; exceeding them cuts output and raises an error surfaceable in HA as a diagnostic sensor for overload detection. |
Unlike the Fibaro Dimmer 2, this Shelly is fixed to trailing-edge output only — there's no leading/trailing mode select, so pair it with trailing-edge-rated LED drivers rather than older leading-edge transformers. Calibration runs automatically on first toggle for a fresh device, or can be forced with a simultaneous hold of both physical buttons, and re-runs itself whenever it senses a load change. A configurable warm-up impulse plus a gamma curve target flicker or no-start behaviour on cheap LED drivers below 10% brightness, worth tuning before writing a driver off as incompatible. Because reported power scales with commanded brightness on this model, an automation can watch for wattage that stays flat despite brightness changes — a cheap signal a driver has failed or isn't actually dimming — and fire a maintenance notification instead of waiting for someone to notice the room looks wrong.
Specs
- dimming
- trailing edge only
- channels
- 1
- max load w
- 200
- dimensions mm
- 38 x 42.5 x 16.5 (H x W x L)
- supply voltage
- 220-240V 50Hz
- standby power w
- 1.5
- power monitoring
- true
- no neutral capable
- true
- bypass required under w
- 20
- max load dimmable led w
- 150
- operating temperature c
- -20 to 40