Goodman AC Running But Not Cooling: Causes & Costs

Last updated Jun 13, 2026 · By fixme.vip Editorial

What’s happening

When a Goodman air conditioner runs but won’t cool the house, the system is moving air but failing to move heat. An AC doesn’t make cold — it absorbs heat from your indoor air at the evaporator coil and dumps it outside at the condenser. Anything that breaks that heat-transfer loop leaves you with air handler running, thermostat satisfied-but-never-reaching-setpoint, and warm or weak air at the registers.

There’s usually no error code on a standard single-stage Goodman condenser — these units have no display, so “not cooling” is a symptom you diagnose by elimination, not a flash code you look up. The job is figuring out which link in the loop is broken: airflow, refrigerant charge, the compressor’s ability to start, or a frozen coil that’s choking the whole system.

Common causes, ranked by probability

1. Dirty or clogged air filter — by far the most common and the cheapest. A restricted filter starves the indoor coil of airflow, cripples heat transfer, and can freeze the coil into a block of ice.
2. Dirty condenser or evaporator coil — a condenser caked in grass clippings, cottonwood, or dust can’t reject heat outside; a dirty indoor coil can’t absorb it. Either one shows up as poor cooling on a hot day.
3. Low refrigerant from a leak — refrigerant doesn’t get “used up,” so low charge always means a leak. Symptoms are weak cooling, long run times, sometimes ice on the lines. This is not a DIY fix — see below.
4. Frozen evaporator coil — caused by restricted airflow or low refrigerant. Ice on the indoor coil or the copper suction line blocks airflow and leaves warm air at the vents.
5. Failing run capacitor — the capacitor gives the compressor and condenser fan the jolt they need to start. A weak or bulged capacitor leaves the fan humming, the compressor struggling, and the unit not cooling.
6. Failed compressor or contactor — less common and more expensive; the heart of the system either won’t engage or has failed outright.

Safe checks before you call anyone

These are the only steps a homeowner should do. None of them involve refrigerant, opening the sealed system, or working inside the live electrical compartment.

1. Replace the air filter. A clogged filter is the single most common cause. Put in a clean filter of the correct size (printed on the old one) and run the system.
2. Set the system to fan-only if you see ice. Frost or ice on the copper lines or indoor coil means the coil is frozen. Switch to fan-only or off for a few hours to let it fully thaw before running cooling again.
3. Clear the outdoor unit. Turn the AC off, then gently rinse leaves, grass, and dirt off the outdoor condenser coil with a garden hose (low pressure, top-down). Keep at least two feet of clearance around the unit.
4. Check the thermostat and breaker. Confirm it’s set to COOL, the setpoint is below room temperature, and the AC breaker hasn’t tripped. Reset a tripped breaker once.

If cooling is still weak after a clean filter, a clear condenser, and a fully thawed coil, stop here. Refrigerant and electrical work inside the unit are technician territory.

How a technician will diagnose it

Knowing this lets you sanity-check a quote:

• Measure refrigerant pressures with gauges and calculate superheat/subcooling to confirm whether the charge is correct — and if it’s low, find the leak rather than just topping it off.
• Test the run capacitor with a meter against its rated microfarads (printed on the capacitor) and check the contactor for pitted or stuck contacts.
• Measure temperature split (return air vs. supply air) — a healthy system usually drops the air 16–22°F across the coil.
• Inspect both coils for dirt and the evaporator for icing, and check the compressor’s amp draw and start behavior.

Symptom, cause and what to do

Repair costs

• Air filter: $5–$30 (DIY)
• Coil cleaning (condenser/evaporator): $100–$400 depending on access and severity
• Run capacitor (with diagnosis): $150–$450
• Contactor: $150–$350
• Refrigerant leak diagnosis + repair and recharge: $200–$600 to find the leak, often $1,000–$2,500+ once the repair, recharge, and any coil replacement are included
• Compressor replacement: $1,500–$2,800+ — on an older unit, often the point where replacing the system makes more sense

A diagnostic service call is typically $89–$200, usually credited toward the repair if you proceed.

Refrigerant is EPA-regulated. Under Section 608 of the Clean Air Act, handling refrigerant requires certification, and any “low Freon” repair must include finding and fixing the leak. Never add refrigerant yourself, and be wary of anyone who tops off a system without locating the leak first.

Related codes

• Honeywell thermostat blank screen / no power — if there’s no cooling and no thermostat display, start there; it may not be the AC at all.
• Frozen evaporator coil — the icing condition that often hides behind “not cooling,” usually traced back to airflow or low charge.
• AC outdoor unit not turning on — a related no-cool case where the condenser never starts (contactor, capacitor, or float-switch lockout).