AC Running But Not Cooling Enough in Chicago?

AC not cooling enough: the short answer

When an AC runs but the house never reaches the set temperature, the system is working below its capacity. The common reasons are low refrigerant, a dirty condenser coil outdoors or a dirty evaporator coil indoors, a failing capacitor, leaky or undersized ductwork, a system too small for the house, or equipment more than about twelve years old that has lost capacity. SAVA HVAC & Appliance Repair tests for each of these across Chicago and the suburbs: an EPA Section 608 Certified technician finds which cause applies and gives you the repair price. The service call starts from $79 with a 30-minute diagnostic, credited toward the repair. Call (773) 558-3332, Monday through Saturday, 8 AM to 6 PM; the emergency line is answered 24/7.

Common causes of AC not cooling enough

1. Low refrigerant

The most common cause of gradual capacity loss. Refrigerant doesn't get 'used up' — if it's low, there's a leak. Symptoms: longer cooling cycles, slightly warmer air from vents, ice on the lines, higher energy bills. Fix requires finding and sealing the leak, then recharging.

2. Dirty condenser coil (outdoor unit)

The outdoor coil rejects heat from your home into the outside air. When it's covered in dirt, grass clippings, cottonwood fluff, or debris, heat transfer drops dramatically. Cleaning is part of annual maintenance.

3. Dirty evaporator coil (indoor)

Same issue inside — dust insulates the coil and reduces its ability to absorb heat from your air. The indoor coil sits behind a sealed panel, so this one is only visible once the system is opened up, and it is part of what we check on site.

4. Failing capacitor

A capacitor that's degrading (not yet fully failed) reduces compressor efficiency. The system still runs but with less cooling capacity. Capacitor testing identifies degraded units before they fully fail.

5. Leaky or undersized ductwork

If your ducts leak in the attic or basement, you're cooling unconditioned spaces. Look for dust streaks at duct seams. Sealing duct leaks can restore 10-30% of capacity.

6. Undersized system

If your AC was sized for the home before an addition, or the previous owner installed a unit too small for the square footage, it may simply lack the capacity to keep up. We measure this with a Manual J load calculation.

7. Aging system (12+ years old)

AC systems lose efficiency over time. A 15-year-old system may run 30-40% less efficiently than when new. Repair is often the right call, but at 12-15 years, replacement starts to make economic sense — we give advice either way.

What to tell us when you call

The more you can describe, the better the chance we arrive with the right part already on the truck. It helps to know:

1. Is it cooling at all, or running constantly without reaching the set temperature?
2. Is it worse in certain rooms, or throughout the house?
3. Did it decline gradually, or change suddenly?
4. Is the outdoor unit's coil visibly dirty, or blocked by plants or debris?
5. How old is the system, and when was it last serviced?

When to call SAVA

If your AC is running long cycles or not reaching set temperature even on mild days, schedule a diagnostic. Catching capacity loss early prevents compressor failure — which is the most expensive AC repair.

SAVA is a family-owned, EPA Section 608 Certified HVAC company serving Chicago and North Shore suburbs. We diagnose the exact fault first, carry common parts for same-day repairs, and give repair-versus-replace guidance. Learn more about our AC repair service or emergency AC repair.

Brands we service

Plus most other residential central AC brands — if yours isn't on the list, call and we'll confirm.

Frequently Asked Questions