Sonoff smart heater

Hi, I’ve made my ordinary electric heater smart using the Sonoff WiFi switch and Home Assistant. I describe in detail how I did it in this blog post. Any feedback would be appreciated.

Switches in Home Assistant:

You could make it even smarter by adding a temperature sensor, and integrating the two using the generic thermostat component, and make sure in the part where your temperature sensor is you get the desired temperature! For this to work properly you’d need to set the heater’s thermostat all the way up.


I love that you have included all the equations to help people with finding the right bits.

The only thing that worries me is if the heater goes faulty, and trys to draw more amps than the sonoff can safely handle. Does that socket have a fuse in it ? Or does the plug have a fuse for below the sonoff max rating ?

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Nice tidy installation. However the heater isn’t particularly smart yet. Being able to switch it on and off from a computer doesn’t make it smart.

Adding a thermostat from a temp sensor, and also analysing the power consumption from the POW will make it really smart, and there will be a further blog post no doubt. :slight_smile:

I’m also a bit worried about this. Is everything fused like it is supposed too, so your SonOff doesn’t catch fire in case something goes wrong with your heater ?

This depends what the fuse board fuse is set to trip at. If it is a 20A fuse, you need to put a 16A fuse in front of the sonoff. If it is 16A or less it should trip when the current exceeds the sonoff’s capability.

That’s a very good idea and I definitely want to do it! Also I found out there’s a 16A Sonoff with humidity and temperature sensors built in. But I agree with you it will be better to have the sensors in a busier part of the room.

Good catch! I should mention this in the blog post. The Sonoff is rated at 16A and my fuse board is also set to 16A. I believe this will prevent the fire scenario from happening.