The answer to 'dehumidifier blowing hot air' is that a dehumidifier blowing hot air is a common issue that can be caused by a few different problems. The most likely causes are a blocked or dirty air filter, a refrigerant leak, or a problem with the compressor.
If the air filter is blocked or dirty, it can restrict airflow and cause the dehumidifier to work harder, resulting in hot air being blown out. This is an easy DIY fix - simply clean or replace the air filter. If the refrigerant is low due to a leak, the dehumidifier will have to work harder to remove moisture, also causing hot air. This requires a professional HVAC technician to diagnose and repair the leak. Finally, an issue with the compressor can lead to hot air being blown out, and this is also a problem that needs professional repair.