If you have an ultrasonic cleaner you will have long ago realized how long the built in heater takes to heat up the tank of liquid. On top of that there is a theory out there that the built in heater(s) are what overheats the electronics on the cleaners and overheating results in premature failure.
When I bought my cleaner I went to a couple of thrift stores and found the biggest electric kettle I cold lay my hands on. When I want to use the Cleaner I fill the kettle from the drain hose, heat it up and pour the heated water back into the tank. Usually takes 2-3 fills to bring the tank up to Temp and then turn on the cleaner. Way faster and potentially service life extending on the cleaner. Once turned on (ultrasonic buzzer only) the water heats up further without the heater.
If you use anything other than water be aware that when boiling many solutions will overflow the kettle so start with a half full kettle and see how it reacts.