If your central AC is running but the house is not cooling, describe what the system is doing before deciding which part has failed. Warm supply air, weak airflow and a thermostat that never reaches its setting can have different causes. A useful service request makes those differences clear.
Your first step
Record the thermostat setting, indoor temperature, affected rooms and when the problem began. Observe only equipment you can reach safely. A symptom is information for a diagnosis; it is not proof that the system needs refrigerant or a new compressor.
Separate three cooling complaints
| What you notice | What to report |
|---|---|
| Air moves, but feels warm | Whether the thermostat calls for cooling, when the change began and whether all rooms are affected. |
| Very little air reaches the rooms | Which vents have weak airflow, whether doors affect it and whether this is a new problem. |
| The home cools, but misses the setting | The time of day, indoor temperatures, recent changes and whether it used to perform differently. |
A longstanding hot bedroom should not be described as a whole-house sudden failure. Likewise, a system that stopped cooling yesterday deserves a different investigation from one that struggles only during unusual outdoor conditions. Tell the technician about a recent filter change, thermostat change, power interruption or previous repair without assuming the event caused the fault.
What you can check without opening equipment
- Read the thermostat mode, setpoint and displayed messages. If the controls are unfamiliar, use the operating instructions rather than changing installer settings.
- Look at accessible supply and return openings for obvious obstructions. Note where airflow feels different; do not remove equipment panels.
- If the filter is user-accessible and you know the manufacturer’s procedure, note its condition and replacement date. Use the specified filter rather than guessing a different type.
- Record safely visible ice or water. Do not handle wet electrical equipment or chip ice off a coil.
- Write down what you hear and when, without reaching into a fan or cabinet. A recording from a safe position may help describe an intermittent sound.
If you see smoke, sparking or water at electrical equipment, keep clear and seek appropriate urgent help. Do not use repeated resets or keep forcing operation after abnormal behavior. Ask a qualified technician how the system should be left while waiting. Cooling loss can also create a household heat risk: make safe arrangements for vulnerable occupants rather than relying on an appointment time that has not been confirmed.
Why “just add refrigerant” is not a diagnosis
Refrigerant, airflow, controls and equipment condition are technician-level questions. A warm-air complaint alone does not tell you which applies. Ask what was measured, what finding explains the loss of cooling and whether further investigation is needed. Do not buy refrigerant or use a DIY recharge kit.
If refrigerant work is proposed, request a description of the issue, the repair scope and what remains uncertain. A quote for refrigerant service should identify what it includes; it should not silently become a complete replacement recommendation. Keep the written diagnosis so a later estimate or second opinion can address the same finding.
A clear request you can adapt
“My central AC has not cooled normally since [date/time]. The thermostat is set to [setting] and reads [temperature]. Airflow is [normal/weak] in [rooms]. I noticed [safe observation]. The last service or control change was [date]. Please confirm the visit fee, service for this equipment and the available arrival window.”
Leave fields blank if you do not know them. Do not climb, enter an unsafe attic or open a cabinet to obtain a model number. If you rent, contact the property owner or manager about authorization. Confirm the provider handles the installed system and exact address before agreeing to a visit.
After the diagnostic visit
- Ask for the finding in plain language and the work recommended to address it.
- Separate the visit fee, repair price, additional diagnostic work and any conditional charges.
- Ask what comfort problem the repair should resolve and what existing limitation may remain.
- If replacement is offered, obtain a complete installation scope so you can compare it with the defined repair.
- Keep the invoice and equipment information for any return visit or warranty question.
There is no universal rule that warm air means an old AC must be replaced. The repair-or-replace decision guide helps compare a documented diagnosis with a complete alternative. For arranging diagnosis, use the AC repair resource. For a large project, review how to compare HVAC estimates.
Technical reference
Carrier’s AC not cooling resource discusses multiple possible causes. It does not establish the cause in your home; diagnosis and component-level work belong with a qualified professional.
If you notice ice, use the freezing-up observation checklist. For water near the indoor unit, record its location and timing using the indoor leak guide. Keep those details with the diagnostic request.