Start with the two-minute checks
Confirm the thermostat is on COOL and set below room temperature, then pull the filter. A packed filter is the single most common cause of weak cooling — it starves the system of airflow until the indoor coil ices over. Next, walk outside: the condenser needs clear space to dump heat, and cottonwood fluff, grass clippings, and hedge overgrowth choke it every Iowa summer. Shut the system off and gently rinse the fins with a garden hose.
The frozen-coil trap
If you see ice on the refrigerant lines or the indoor coil, more cooling is not the answer — the ice itself blocks airflow, and running the system just makes it worse. Switch cooling off, run the fan only, and let it thaw completely (a few hours). If it freezes again after a filter change, the cause is low refrigerant or an airflow problem that needs professional diagnosis.
Low refrigerant deserves emphasis: refrigerant is not consumed like fuel. If the system is low, it leaked, and topping it off without fixing the leak just rents you a few weeks of cooling. A proper repair finds and fixes the leak, then charges the system to specification.
When the AC runs constantly on humid days
Central Iowa humidity is brutal on cooling systems. A correctly sized AC should cycle off periodically even in July; one that runs from noon to midnight without reaching setpoint is undersized, failing, or fighting duct leakage. Two settings help immediately: keep the fan on AUTO (running it on ON re-evaporates moisture off the coil back into the house), and don't set the thermostat lower than you actually want — it doesn't cool faster, it just runs longer.
Call a professional when you see:
- Ice returning after the filter has been replaced
- The breaker tripping repeatedly (see our breaker guide — it's protecting you)
- Warm air from vents with the condenser running
- Hissing or bubbling sounds near refrigerant lines
- Water pooling around the indoor unit
Free diagnostic on broken ACs
True Comfort currently offers a FREE diagnostic on broken air conditioning systems — with no after-hours, weekend, or overtime charges. Same-day service is common across the Greater Des Moines Area, and you'll get an honest assessment with a fixed written price before any work begins.
Frequently asked questions
Why is my AC blowing warm air?
The usual causes, in order of likelihood: thermostat set wrong (fan ON instead of AUTO), a clogged filter, a tripped outdoor breaker, a dirty condenser coil, or low refrigerant from a leak. Check the settings, filter, and breaker yourself; refrigerant and coil issues need a technician.
Why is there ice on my air conditioner?
Ice means the evaporator coil is getting too cold, almost always from restricted airflow (dirty filter, blocked vents) or low refrigerant. Turn cooling off, let it thaw fully, and replace the filter. If it ices again, have it professionally diagnosed — continuing to run it can damage the compressor.
Is it normal for the AC to run all day in an Iowa summer?
On the hottest, most humid days a system will run long cycles, but it should still reach your setpoint and cycle off. Constant running that never catches up signals an undersized or failing system, duct leakage, or refrigerant loss — worth a professional look before it becomes a breakdown.
Does True Comfort charge extra for weekend AC calls?
We currently offer a free diagnostic on broken air conditioning systems with no after-hours, weekend, or overtime charges — and True Comfort Savings Plan members never pay an after-hours fee on any service.
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