To prevent disputes over additional costs, the compact reference book "ABC of Rental Additional Costs" reliably informs how to correctly prepare utility bills and which details to pay special attention to in the statements. Which items can be included in the operating cost statement? When is an increase in the advance payment for operating costs permissible? What does a correct rental additional cost statement look like? How do you check the statement from your landlord or property management? How do you assert your rights in the case of excessive statements? What should be considered in an operating cost agreement? How can claims for back payments and credits be enforced? How do you verify the accuracy of your heating cost statement? What special rules apply to rented condominiums? Which costs for the installation of a new heating system or other measures under the new Building Energy Act can be passed on (e.g., PV system, solar thermal, combined heat and power plant, heat pump)? With selected legal foundations and court decisions.