@Loimarie-Nor0, regarding your first question: I emphasise that my listing is ecofriendly and ask guests to be mindful of power and water use. I also specifically ask them to turn off their bedroom heater when they go to bed or go out. Other than that, there's probably not much you can do except to reflect it in your rate.
Regarding your second question: your guest must send you an alteration request through the booking platform. Once you accept, they will be automatically charged.