Appliances that adjust the temperature of the air in the dwelling place for human living in the cold, or not too cold, or use air treatment, for any other purpose.
Appliances that adjusts the temperature of the air in the dwelling. So that humans can live in a hot or too cold. Or to maintain a stable climate for other purposes.
Electrical appliances used to adjust the temperature of the air in the housing So humans have lived in what is not hot or too cold. Maintain constant air or used for other purposes