A lot of things can go wrong with your cooling system.
First, it can get dirty. Have you checked your air filter recently? The air filter is responsible for stopping dust and dirt getting into the system. If you don’t regularly clean it, then your AC gets stopped up with dust. It works sluggishly and ups your energy bills. The dust is also bad to breathe in. Has your AC started leaking water? That might be an issue with the condensate drain. It can clog with algae and cause it to overflow with water. It is quite easy to muck it out and dump vinegar in the machine. Another concern is mildew on the cooling coil. Again, an easy fix and totally necessary. Your AC also can easily cause high energy bills. Make sure you take care of your air conditioner. I highly recommend getting yearly cooling service. Some people even do it two times a year. First an air conditioner tune up in the spring is necessary. This is a check up on all the moving parts where the HVAC dealer can add lubrication, clean off debris and replace any worn pieces. Then the air conditioner is good to go for the season and will run efficiently. Before you turn off your AC for good in the fall, have the HVAC contractor look at it again. It is possible a repair could have formed or mildew is deep in the system. You want to ensure it is in good shape. The better shape your AC is in, the lower the energy bills.