GF have just introduced Firmware 1.8 for the G40, which gives the option to vary power during the boil. I used it today and it really is a great feature: I boiled at 85% power, which gave a nice rolling boil without the excessive activity of a full power boil. A small saving in electricity and a useful saving in steam generated. This will be a vital feature in using the G40 with a steam condenser, which I intend to do during the winter months when humidity is higher and steam is harder to blow away with a fan.