The invention relates to an air-conditioning device for a space to be air-conditioned. The air-conditioning device has a housing including an air supply and an air discharge. In the housing, a flow path is formed between the air supply and the air discharge. In the flow path, at least one heat exchanger, a blower, and a means for generating an excited gas are provided. Furthermore, a surface coating is provided in the flow path, which is configured for the catalytic decomposition of the ozone content of the excited gas, and which is arranged downstream of the means for generating the excited gas.