The heat is regulated using a set point that you specify, or you can choose a fixed high or low heat setting, or just ventilation mode.
Personally, I don't find the automatic control fantastic because it's on the fan, so it just switches on and off until the temperature returns to room level each time. So I put it on high mode.
Good point: you don't have to worry about it, it manages the room temperature.
Negative point: if you want it to heat a bathroom quickly while you're showering, for example, it's not the fastest, but overall it's a good buy.

The heat is adjustable, but the power is set by the appliance and cannot be changed.