AC Running Constantly: Causes of Long Run Times

Why an AC may run nearly nonstop, including extreme load, airflow restrictions, thermostat issues, duct losses, dirty coils, and equipment problems.

Long run times are not automatically a failure—air conditioners can run for extended periods during high cooling load—but nonstop operation with poor comfort deserves attention.

Things that can contribute

• Dirty filter or restricted airflow
• Thermostat setting or location
• Dirty heat-transfer surfaces
• Duct leakage or major airflow imbalance
• Cooling-capacity or refrigerant-side problems

If your system is older and repair needs are increasing, compare repair vs. replacement.

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