@Sissel-Marie0 this is your expense like any other. You will need to adjust your prices accordingly. Figure out the average and build it into the price. Most people are not going to conserve when they are on vacation and it is not their own home/money.
I always turn off lights at home when I leave but have to admit that not as thorough when traveling. Most of my guests leave lights on at all times. Some do laundry several times a day and run heat like it is a sauna. Realistically there is nothing I can do about it but build into my pricing.