Check the Thermostat Settings
It sounds stupid. Check it anyway. Make sure the switch is set to Cool and not On. If it is set to On, the fan runs 24/7. It blows air even when the AC compressor is resting. That air will feel warm. Switch it to Auto.
The Cottonwood Problem
If you live in Greater Cincinnati, you know about May and June. The cottonwood trees drop fuzz everywhere. It gets sucked straight into your outside unit. It also clogs your indoor furnace filter fast. A choked system cannot cool the air. Go look at your air filter right now. If it looks like a gray sweater, change it.
Dirty Condenser Coils
Your outside unit is the condenser. It needs to breathe to dump the heat from your house. Dirt, grass clippings, and leaves block the airflow. The compressor overheats. When it overheats, it stops cooling. You can lightly wash the outside metal fins with a garden hose. Do not use a pressure washer. You will bend the fins and ruin the unit.
Low Refrigerant Levels
Air conditioners do not consume refrigerant. If you are low, you have a leak. Period. Running the system with low refrigerant will burn out the compressor. A warm vent is the first sign. You might also hear a hissing noise near the outside unit.
What to Do Next
If you changed the filter and the settings are correct, turn the system off. Do not let it run. It will just spin your Duke Energy meter and hike up your bill. Give us a call. We charge an $89 diagnostic fee to come out and pinpoint the exact issue. With our Repairs First policy, we focus on fixing the broken part, not forcing you into a whole new system.