I am in a rental and the bathroom has a pull cord heater (see image below) I don’t really want to get out of bed in the morning to turn on the heater 20 mins before I have a shower.
Hi there, There are a few ways with which you are sort this.
The easiest would be to use a smart plug at the wall socket were this heater is plugged in and then operate it with the pull chord kept in ON position. You can even time the smart switch to cut off at 20 minutes.
A hard method would be to open the device and replace the pull chord switch with a relay and an ESP module which could turn the water heater on and off. You would need necessary tools and expertise for me same.
There would be other methods also but these are things that come to my mind now. Keep in mind I dont know what is the model or make of this heater and so these are general suggestions.