I created "heater" in my beginnings with IoT for Raspberry Zero W. It is obviously a huge overkill to use Raspberry for switching (single) relay, but hey, it was cold and I wanted to control my heater remotely. It worked well for one winter, however I've rebuilt this in C++ for ESP8266 which suits the purpose much better.
Few things to note
- heater.go is the original version which blinks the status LED, so you know it is running
- heater_pi-blaster.go as the name suggest is the 2nd version (final) which utilizes the pi-blaster to dim the LEDs
- oh and it uses ds18b20 sensor, so you know which temperature is around your heater. Sounds useless? It actually is.