Smart bathroom extractor fan

[werth]

Just looking some advice on making my bathroom extractor fan smart.
Just trying to figure out the hardware side of things atm.
For context I’m in the UK.

After some research it seems that 2 most popular options are Shelly and Sonoff switches.

I found an post saying that Shelly shouldn’t be used for an inductive load like fan.
Does anyone know if that applies for Sonoff as well? Those of you who have done something similar, how did you deal with this?

[itnassol (Andrew)]

I have an inline fan, connected to a standard 13 Amp outlet, I then put one of these in.

Zibbee Outet

The sensor then turns the fan on when the humidity get too high. I have been very impressed with these very stable and can hold a good current.

[Jonah1970 (Mark)]

Hi, I use one of the Girier Zigbee switch modules below to control my 3 speed extractor based on humidity i.e. if the humidity spikes due to someone having a shower then I run the fan at higher speed for a set period of time.

As shown by the diagram within the fan I just need to switch 240Vac onto terminals 1, 2&3, or 3 to select different speeds.

This is what the device looks like in HA:

Essentially I have it setup as follows:

Low Speed - background ventilation.
Medium Speed - run for a set period after the humidity spikes (this is from an Aqara sensor).
High Speed - runs when the light is switched on (this is as it was originally installed).

Hope that’s useful to you.

[ChrisThomas]

Have a look at this blueprint, I find it works a treat, took a while to get the settings right for my installation but then it just works!

Bathroom Humidity Exhaust Fan

[Open your Home Assistant instance and show the blueprint import dialog with a specific blueprint pre-filled.] GitHub Link Click Here Step into the future of freshness – customize it your way and let the automated fan system handle the humidity control for you! Like this blueprint? Consider hitting the button below Version: 2.3 Need help? See our FAQ: Click Here The Automation Process: When the humidity rises above a set percentage va…

[orange-assistant (the real one)]

@werth

Just looking some advice on making my bathroom extractor fan smart.

Dumb Extractor Fan + esp32 based wall switch (includes BLE ) supercharged with esphome + BLE Hygrometer =

@orange-assistant

could build his wall switches around this Sonoff M5 wall switches

M5 - SONOFF Official

And make use of esphome on it

https://esphome.io

As this thing runs an esp32 it can act as a bluetooth proxy

Bluetooth Proxy — ESPHome

Literally all that it needs is to add two lines to the yaml to extend the esphome node for that functionality.

bluetooth_proxy:
  active: true

Now the wall switches can receive ble broadcast like from this little cheap xioami hygrometers

https://bthome.io/

Even sending data to the display is possible if one takes full control and ownership over the devices.

PVVX MiThermometer Display — ESPHome

@orange-assistant

Another great scenario could be having a esp based wall switch acting as a controller for an bathroom exhaust fan connected to the local relay and receiving temperature and humidity wireless from such a little xioami thingy. The climate components available for esphome should have anybody covered for such a resilient setup which even will do it’s dedicated task when ha is not available (maybe restarting for an update?) or wifi is down because the power supply gave up

@werth

I found an post saying that Shelly shouldn’t be used for an inductive load like fan.

Poorly worded I would say. The maximum specifications for loads are typical for resistive ones. So if a device says it can handle 16A (or 10A) you shouldn’t put a inductive load with 16A (or 10A) but stay within more or less than 50%. That’s because inductive loads actually often use double the rated power at one time and no power the next moment (that happens very fast obviously)

[werth]

@orange-assistant

Poorly worded I would say. The maximum specifications for loads are typical for resistive ones. So if a device says it can handle 16A (or 10A) you shouldn’t put a inductive load with 16A (or 10A) but stay within more or less than 50%. That’s because inductive loads actually often use double the rated power at one time and no power the next moment (that happens very fast obviously)

Thanks, this is just what I was looking for.

However I came across this on shelly support forum (My Shelly relay is restarting when switching on inductive load - such as fans, motors, roller. What should I do? :
)

Q: My Shelly relay is restarting when switching on inductive load - such as fans, motors, roller. What should I do?
A: To avoid that a RC snubber should be wired between Output and Neutral of the circuit. Еnergy absorbing circuits are used to suppress the voltage spikes caused by the circuit’s inductance when a switch, electrical or mechanical, opens.

Maybe that’s what I end up doing.