Why is my energy bill so high since I started renting out?

Your bill is higher because you now pay for your own consumption and that of guests combined, without seeing those two separately. Guests don't account for an annual statement, their consumption often peaks in the same months that heating or cooling is already working hard, and appliances such as a charging station can use as much in one night as you do in several days. Compare your energy costs per rented night with those of vacancy to see how much guests actually cost you. With little rental or low consumption, this difference is small; with multiple properties or high rental volume, it is usually a structural amount.