The answer to 'why is my dehumidifier blowing cold air' is that it is likely a sign of a problem with the dehumidifier's refrigeration system. Dehumidifiers use a refrigeration cycle to remove moisture from the air, and if this system is not working properly, it can cause the air being blown out to feel cold.
Some common causes of a dehumidifier blowing cold air include a refrigerant leak, a problem with the compressor, or a clogged air filter. If the refrigerant level is low, the coils can get too cold and cause the air to feel chilly. A failing compressor or a blocked air filter can also disrupt the normal operation of the dehumidifier, leading to cold air being blown out.