The summer call we get every July is the same. “The AC is running, but it's blowing warm air.” Nine times out of ten that's either a refrigerant leak, a frozen evaporator coil (often from a dirty filter restricting airflow), or a failed capacitor on the outdoor condenser. All three are fixable on the first visit if we get the call early.
Central AC repair: common failures
Most Glen Ellyn and Wheaton homes run a split-system central AC. An outdoor condenser unit and an indoor evaporator coil mounted above the furnace. Common failures by component:
- Capacitor failure. The condenser hums but the fan won't spin. Cheap part, fast fix.
- Contactor pitting. System short cycles or won't engage. Common after 8 to 10 years.
- Refrigerant leak. System slowly loses cooling capacity. We leak-test and locate the source before adding refrigerant, because topping off a leaking system is throwing money at the wall.
- Frozen evaporator coil. Almost always a dirty filter or low refrigerant. Shut the system off, replace the filter, and call us.
- Compressor failure. The big one. On a 12+ year unit, compressor failure usually means replacement, not repair.
Central AC installation
For replacements we install Carrier, Lennox, Trane, Goodman, and Rheem central AC units. SEER2 14.3 is the minimum for new installations in Illinois. We install 14.3 through 18+ SEER depending on the home and the utility rebate window. Sizing is done by Manual J load calculation, not “match the old unit,” because oversized AC short-cycles and doesn't dehumidify properly in our muggy Chicago summers. Permit pulled, inspection scheduled, warranty registered, all included.
Seasonal tune-ups
Get the AC tune-up done in April or early May, before the first 88° day forces every HVAC company in DuPage County into a two-week backlog. We clean the outdoor coil (a winter's worth of cottonwood and pollen kills capacity), check refrigerant pressures, test the capacitor and contactor under load, verify the condensate drain is clear, and check the indoor coil and blower. About 45 minutes per visit.
Thermostat upgrades
Most calls to upgrade an old mercury or low-end digital thermostat are simple. Ecobee, Nest, and Honeywell T-series all install in 30 minutes if the home has a C-wire. If it doesn't, we run one, no drywall damage. If your AC works fine but feels uneven floor-to-floor, sometimes a smart thermostat with a remote sensor in the upstairs bedroom fixes what a duct overhaul would have cost five times as much to address.
In Glen Ellyn proper? Our Glen Ellyn HVAC page covers local AC repair pricing, permits, and same-day service details.