Exceptions are stipulated in Section 2 Paragraph 3 and Section 9 Paragraphs 1 and 2 of the CO₂ Cost Allocation Act (CO₂KostAufG). An exception under Section 9 Paragraph 1 can be justified, for example, by historic preservation regulations or mandatory connection and usage requirements. The latter could be the case if building regulations or the building permit require a mandatory connection to the heat supply. We cannot tell you whether you can make use of any of these provisions. If you are unsure, we recommend that you contact the relevant city or municipal administration directly.