This is the number one call we get every July: the air conditioner is clearly running, the fan is blowing, but the house keeps getting warmer. Work through this list in order — it's sorted from most common and easiest to least common and most serious.
The 7 causes, in the order to check them
Clogged air filter
✓ You can fix thisA packed filter chokes airflow, so the system runs constantly but moves too little air to cool the house. In dusty homes or homes with pets, a 1-inch filter can clog in a month.
Pull the filter and hold it up to a light. If you can't see light through it, replace it and give the system a few hours.
Outdoor unit not running
✓ You can fix thisIf the inside fan blows but the outdoor condenser is silent, the outside unit may have tripped its breaker — common during heat waves and after summer storms.
Check your electrical panel for a tripped "AC" or "condenser" breaker. Reset it once. If it trips again, stop and call — repeat trips mean an electrical or compressor problem.
Dirty condenser coil
✓ You can fix thisThe outdoor coil dumps heat from your house into the outside air. When it's caked in cottonwood fluff, grass clippings, or dirt, it can't shed heat and the air from your vents gets barely cool.
With the power off at the disconnect, gently rinse the outdoor coil fins with a garden hose (not a pressure washer). Keep shrubs trimmed two feet back.
Frozen evaporator coil
Call a pro if it recursWeak airflow or low refrigerant can freeze the indoor coil into a block of ice. The clue: the air handler runs but almost nothing comes out of the vents, or you see ice on the copper lines.
Turn the system OFF and let it thaw (run fan-only if you can). If it freezes again after a filter change, the cause is usually refrigerant or airflow — that's a service call.
Low refrigerant (a leak)
Licensed technician onlyRefrigerant doesn't get "used up." If it's low, it leaked. The system blows air that's only slightly cool, runs nonstop, and your electric bill climbs. Topping it off without fixing the leak just rents you a few weeks.
Handling refrigerant requires EPA certification. We find the leak, repair it, and weigh in the correct charge.
Thermostat problems
✓ You can fix thisDead batteries, a thermostat set to "fan on" instead of "auto/cool," or a failing sensor can all make it seem like the AC is broken when the equipment is fine.
Confirm it's set to COOL, the setpoint is below room temperature, and swap the batteries. If the display is blank or unresponsive, the fix may be as small as a new thermostat.
The compressor is wearing out
Decision time — call a proOn systems 12–15+ years old, a compressor that starts hard, hums, or short-cycles is often the root cause. On an older unit, a compressor replacement can cost a large share of a whole new, far more efficient system.
Ask for both numbers — the repair quote and the replacement quote — before deciding. We give both, with no pressure, on every visit.
Repair or replace?
Our rule of thumb: if the system is under 10 years old and the repair is routine (capacitor, contactor, fan motor, clogged drain), repair it. If it's 12–15+ years old and facing a compressor or coil replacement, get a replacement quote too — today's systems cool noticeably better on less electricity, and with financing with no payments and no interest for up to 12 months (subject to credit approval), replacement is often easier on the budget than a major repair paid all at once.
Either way, an annual AC tune-up catches most of this list before it becomes an emergency — our membership plan includes it automatically.
AC not cooling right now?
Same-day AC repair across South Jersey, Mon–Fri, plus emergency weekend service. Family-owned, 4.8★ on Google.
Serving Camden, Gloucester, Burlington, Atlantic, Cape May, Cumberland, and Salem counties from Runnemede, NJ — see all service areas, explore our cooling services, or browse more homeowner guides.