You can deduct the expenses as income-related expenses to the extent that they are related to the rented apartment. Costs that are directly incurred for the rented apartment are directly attributable to it and are fully deductible. Costs directly attributable to the owner-occupied dwelling are not deductible as income-related expenses. Costs that are attributable to the building as a whole are deductible as income-related expenses in accordance with the living/usable space ratio of the rented apartment to the building as a whole.