Air conditioners · cooling

Air conditioner runs but does not cool the house

Prove thermostat demand, indoor airflow and outdoor-unit operation before considering refrigerant or electrical components.

Direct answer

Prove thermostat demand, indoor airflow and outdoor-unit operation before considering refrigerant or electrical components.

What this covers

  • Residential central air-conditioning and heat-pump systems in cooling mode
  • The exact condition described in the title
  • Customer-accessible checks before internal repair or reset

What it does not cover

  • ×A different brand, model family or similar-looking code
  • ×Internal live-electrical, gas, refrigerant or sealed-system testing
  • ×A guarantee that a named component has failed without isolation
Try in this order0 of 4 completed
  1. Capture the exact state

    Reversible

    Record indoor/outdoor temperature, filter, blower and outdoor fan/compressor sound.

  2. Separate the likely fault domains

    Reversible

    Check power once, filter size/orientation, open registers and exterior debris with power off.

  3. Correct only the proven, accessible condition

    Reversible

    Restore airflow or settings; arrange service for a silent/humming unit, ice, oil staining or warm supply air.

  4. Verify once before going farther

    Reversible

    Confirm steady cool supply air and falling indoor temperature.

Evidence ledger

Sources behind this answer

Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.

Exact questions

Common follow-ups

What should I record first for “Air conditioner runs but does not cool the house”?+

Record indoor/outdoor temperature, filter, blower and outdoor fan/compressor sound.

Does the symptom or code prove a part has failed?+

No. Check power once, filter size/orientation, open registers and exterior debris with power off.

When should I stop troubleshooting?+

Stop for sparks, hot wiring, refrigerant-line damage, smoke or repeated breaker trips.

Change recordAug. 17, 2026 — Added exact scope, evidence class, reversible checks, verification result and explicit stop condition.
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