Check your thermostat and air filter first — those two things cause more than half of warm-air AC calls. If both are fine, the issue is likely low refrigerant, a failed capacitor, or a frozen evaporator coil.
Check These 3 Things Yourself (Free)
1. Thermostat
- Set to COOL (not HEAT, AUTO, or FAN ONLY)
- Set temp at least 3–5°F below current room temp
- Fan set to AUTO, not ON (ON blows unconditioned air between cooling cycles, which feels warm)
- Batteries alive (dead batteries = no signal to the AC)
2. Air Filter
Pull it out. If you can’t see light through it, it’s restricting airflow. A clogged filter causes the evaporator coil to freeze, which blocks cooling entirely. Replace it ($5–$20) and wait 2–3 hours for the coil to thaw before running the AC again.
3. Circuit Breakers
Your AC has two breakers — one for the indoor air handler, one for the outdoor condenser. If the outdoor unit lost power but the indoor blower kept running, you get warm air blowing through the vents. Check both breakers.
Common Causes That Need a Technician
Low Refrigerant
Refrigerant doesn’t get “used up” — if it’s low, there’s a leak. Signs: warm air, the outdoor unit runs but the copper lines aren’t sweating (no condensation), and the system runs constantly without cooling. Repair: $200–$600 including leak fix and recharge.
Failed Capacitor
The capacitor starts the compressor motor. When it fails, the outdoor unit hums but the compressor doesn’t kick on. The fan may spin, but no cooling happens. Repair: $150–$300. This is the most common AC part failure and a 20-minute fix for a technician.
Frozen Evaporator Coil
Caused by dirty filters, low refrigerant, or a dirty coil. The coil ices over and blocks airflow entirely. Turn the AC off, set the fan to ON to thaw (takes 2–4 hours), then call for service to fix the root cause.
Dirty Condenser Coil (Outdoor)
The outdoor coil rejects heat. If it’s caked with dirt, grass clippings, or cottonwood, it can’t release heat effectively. Hose it down gently from the inside out. If performance doesn’t improve, the coil may need professional chemical cleaning.
Powell’s
Plumbing & Air provides
AC repair throughout Winchester, VA, Frederick County, and the Northern Shenandoah Valley.
