If your AC blows warm or hot air, consider it a major issue because it is supposed to provide cool air, and if it does otherwise, there can be a serious problem too.
Low refrigerant levels, dirty air filters, clogged ducts or vents, or an overheating compressor are common causes of this problem. You can clean your ducts, vents, and AC air filter to fix such issues. However, if cleaning and fixing small duct leaks don’t resolve the problem, you will need a technician’s help.