10 signs your AC needs attention before it fails

The ten signs

1. Air that's cool, not cold

Low refrigerant, a dirty coil or a weakening compressor. See AC not cooling.

2. Weak airflow

Start with the filter. If it's clean, suspect a blower problem, a disconnected duct or an iced coil.

3. New noises

Buzzing (electrical: capacitor or contactor), grinding or squealing (motor bearings), banging (something loose), hissing (possible refrigerant leak), or repeated clicking without starting.

4. Short cycling

Running a few minutes, shutting off, restarting. Often an oversized system, a thermostat problem, low refrigerant or a coil icing. It wears the compressor fast.

5. Water where it shouldn't be

A full drain pan, drips from the ceiling, water in the air-handler closet. See AC leaking water.

6. Ice

On the copper line or the indoor coil. Turn cooling off. See frozen coil.

7. A bill that jumped

Compared with the same month last year, with similar weather. The system is working harder for the same result.

8. Smells

Musty (moisture or growth in the air handler or ducts), burning (turn it off now), or sour and swampy (standing water in the pan).

9. Sticky air

Cool but clammy means the system isn't removing humidity. Indoor relative humidity should stay below about 60% (EPA mold guide).

10. Age

At 10–12+ years, especially near the coast or on R-22, it's time to plan rather than wait for the failure. See repair or replace.

What to do

If you notice one sign, do the basic checks: filter, thermostat, outdoor unit clear. If you notice two or more, or any smell of burning, water through a ceiling or ice, call. A diagnosis now is cheaper than an emergency later.