What you're probably noticing
It's August in Nixa, the thermostat says 72, and the air coming out of the vent feels warm. Not hot exactly, just not cold enough to matter. You check the thermostat again, it still says the system is running and cooling, but standing under the vent you'd swear it's barely doing anything.
Before you assume the compressor is dying or the refrigerant is low, check one thing most people never think about: the fan setting on the thermostat. There's usually a switch or menu option for "On" and "Auto." That one setting changes how the air feels even when the cooling itself is working fine.
Why the fan setting matters so much here
Set the fan to "On" and it runs constantly, even when the compressor isn't actively cooling. In a lot of the country that's a minor inefficiency. In the Ozarks, with our humidity sitting heavy from June through September, it's a bigger problem. A fan that runs nonstop blows air across a wet evaporator coil after the cooling cycle ends, picks up that moisture, and pushes it right back into your living room.
The result is air movement without the dryness that makes cool air feel cool. Humidity is what makes 85 degrees in Nixa feel worse than 85 degrees somewhere dry. The same principle works in reverse indoors. Switch that fan to "Auto" and it only runs while the compressor is actively cooling, which means the coil has time to drain and the air it pushes out stays drier.
More on this from Redeemed HVAC.
What to check yourself
Go to the thermostat and look at the fan mode. If it's set to "On," switch it to "Auto" and give it a day. A lot of homeowners in older Nixa neighborhoods, especially the ranch-style homes built in the 60s and 70s around the downtown core, inherited thermostats from a previous owner with the fan left on constantly, sometimes for years, without anyone noticing.
While you're at it, check the air filter. A dirty filter restricts airflow, which makes the coil run colder and ice up, and iced coils make the warm-air problem worse, not better. Filters in this area tend to clog faster than people expect because of pollen loads in spring and dust from gravel roads common outside the city limits.
If you have a window unit or a mini-split in an add-on room, the same fan logic applies. Check that it isn't stuck on continuous fan mode too.
When this isn't the whole story
Switching to Auto fixes the
problem for plenty of households, but not all of them. If the air still feels warm and weak after a day on Auto, something else is going on. That could be low refrigerant from a slow leak, which is common in systems installed before the mid-2000s and now aging out in a lot of Christian County homes. It could be a failing capacitor making the compressor cycle short and ineffective, which shows up more in late summer when the system runs hardest.
A clear sign it's past the thermostat setting: the outdoor unit is running, you can hear it, but the air at the vent stays lukewarm for more than a few minutes after a cooling cycle starts. Or the system seems to run constantly and never quite reaches the set temperature, especially on the 95-degree afternoons we get through July and August.
Where to stop and call someone
If the fan setting was the only issue, you'll know within a day, the air gets noticeably crisper and the house stops feeling clammy. If nothing changes, stop guessing. Opening up the outdoor unit or handling refrigerant lines isn't a homeowner repair, and running a system low on refrigerant for weeks can damage the compressor, which turns a moderate repair into a full replacement.
Nixa summers don't give you much room to let a cooling problem sit. The humidity off the lake and the surrounding farmland keeps the air heavy well into September, and a system that's struggling in July usually isn't fixing itself in August. Check the easy things first, but once you've ruled out the fan setting and the filter, it's time to get someone who can test the refrigerant charge and check the electrical components properly.