Smart plug with built-in temperature sensor? for controlling room heaters


I am looking at setting up a simple automation with HA, to automatically turn on/off an electric ceramic/wall heater depending on temperature. I actually have one of these heaters in each room of the house, including three in a central corridor that crosses the center of the (single-floor) house, so I’ll apply the same solution for each.

I thought I’d be able to pull this off easily with some wifi or zigbee smart plug with built-in temperature sensor. Ideally a plug with energy/power monitoring as well.

Thing is, I can’t seem to find such a device. Seems like smart plugs don’t come with temperature sensors? Does “everybody” install battery powered Zigbee temperature sensors? I hate batteries, though, would really like to avoid them if possible. I understand that if the temperature sensor is low near the floor, and, near the heat source, the temp readout won’t be accurate compared to a read where humans really are, but I think that I can just apply a bias offset and I’ll be good.

Any recommendation for such a device? Or pointers to alternatives?

One more thing, I’m in Europe.

I hate battery powered devices too, but I have found a way to power them from the mains.
I bought USB stepdown converters on AliExpress, which means a USB adapter can be converted to 3V3 or 5V, which is equal to 2 batteries or 3 batteries.
I simple just get two round piece of wood around the same or a little less than the diameter of a battery and a length a bit less too.
Then I put a screw in one end and connect one of the wires from the two pins needed from the USB stepdown converter to that screw.
Then it is just a question about adjusting the screw and plug it into a USB adapter, where the old 0.5A and 1.0A works perfectly and many often have a bunch of those laying around from old devices.

Here is the link to the USB stepdown converter.
It is for 18 pieces, but there are smaller packages, but here it is better to buy many if it get caught in the custom and fees are added and it is always nice to be able to remove some batteries when you get the idea and dont have to wait for China to mail the stuff needed. :slight_smile: