An interesting observation after setting up my aquarium monitoring system is that typical thermostat heaters actually show oscillatory behaviour. Since they startup based on a temperature threshold and stop based on a cut off they oscillate with varying periods based on external temperatures.
I was expecting large variance since this wasn’t an expensive heater but surprisingly all values were within 1°C. I would likely attribute this more to hysteresis rather than the heater.
Follow up post under: https://adam-s.ca/follow-up-on-aquarium-thermostat-heaters/