I meant controlled by the thermostat. I'm sure you can adjust it manually, but in normal operation, it's cycling between on and off, and nothing more. Output level when heating your house from 50F to 70F is the same as heating your house from 69F to 70F, it just runs longer.

I'm sure there are exceptions to this somewhere, but it doesn't seem common. Thermostats don't typically have a way to command anything besides on and off.