When an air conditioner runs but the house never cools, the cause can range from a simple airflow issue to a failing compressor, and in summer heat the problem rarely waits. Most AC repairs cost between $150 and $650, while a major component like a compressor can exceed $1,500, but the price you actually pay depends heavily on local factors: the specific failure, your system type, and how quickly a licensed HVAC technician in your area can respond.
Because HVAC labor rates and seasonal demand vary sharply from one zip code to the next, there is no single national price for an AC repair. The reliable way homeowners find their real cost is to compare current quotes from licensed HVAC technicians serving their local area. Below are the most common reasons an AC stops cooling, what each typically costs to fix, and when the issue needs a professional.
Common Reasons Your AC Is Not Cooling
Most cooling failures trace back to a handful of causes, ranked here from simple to serious.
Dirty Air Filter or Blocked Airflow: A clogged filter restricts airflow and reduces cooling. This is the most common and least expensive issue.
Low Refrigerant or a Leak: If refrigerant is low, the system cannot remove heat. A leak requires a professional to locate and seal, then recharge the system.
Frozen Evaporator Coil: Restricted airflow or low refrigerant can freeze the coil, blocking cooling entirely until it is diagnosed and thawed.
Faulty Capacitor or Contactor: These electrical parts start and run the system. When they fail, the unit may run without cooling or not start at all.
Failing Compressor: The most serious and costly failure. A bad compressor often means a major repair or system replacement decision.
AC Repair Cost Table
If a professional diagnosis confirms the system is otherwise sound, an isolated repair often restores cooling without a full replacement.
| Repair Type | Average Cost Range | Typical Cause | Local Market Variance Impact |
|---|---|---|---|
| Capacitor Replacement | $150 – $400 | Unit runs but won’t cool or start | Labor rates and travel distance affect pricing |
| Refrigerant Leak & Recharge | $200 – $750 | Low refrigerant from a leak | Leak location and system type vary locally |
| Evaporator Coil Service | $300 – $1,000 | Frozen or fouled coil | Accessibility and technician demand affect cost |
| Compressor Replacement | $1,200 – $2,800+ | Failed compressor | Unit capacity and contractor demand affect pricing |
Repair or Replace? The System Age Rule
HVAC technicians typically weigh the unit’s age against the repair cost.
If the system is under 10 years old and the failure is a capacitor or refrigerant issue, a repair usually makes sense. If the unit is 12 to 15 years or older, or the compressor has failed, replacement often provides better long-term value and efficiency than a costly repair on an aging system.
Comparing a repair quote against a replacement quote based on your system’s age and type helps you make a more informed decision.
AC Replacement Cost by System Type
| System Type | Installed Cost Range | Best For |
|---|---|---|
| Central AC (replace condenser) | $3,500 – $7,500 | Existing ductwork, like-for-like |
| Full Central AC System | $5,000 – $12,000 | Aging system needing full replacement |
| Heat Pump | $4,500 – $10,000 | Year-round heating and cooling |
| Ductless Mini-Split | $3,000 – $8,000 | Homes without ductwork |
When to Call a Professional
Some issues are not safe or practical to troubleshoot without training and tools.
If the unit is blowing warm air despite a clean filter, if you hear grinding or clicking, if ice has formed on the lines, or if the system trips the breaker, a licensed HVAC technician should diagnose it. Refrigerant and electrical work require professional handling, and a fast diagnosis often prevents a small fault from damaging the compressor.
Frequently Asked Questions
Why is my AC running but not cooling? Common causes are a dirty filter, low refrigerant, a frozen coil, or a failed capacitor. A technician can pinpoint which one and quote the repair.
How much does it cost to fix an AC that won’t cool? Most repairs run $150 to $750. A compressor failure can exceed $1,500, which is when replacement is often considered.
Can I fix my AC myself? Filter changes are fine, but refrigerant and electrical components require a licensed technician. Incorrect handling can damage the system or be unsafe.
How long do AC systems last? Most central systems last 12 to 15 years. A major failure near or past this age usually points toward replacement.
Why is my AC freezing up? Restricted airflow or low refrigerant are the usual causes. It needs a professional to diagnose, since running a frozen unit can damage the compressor.
Comparing Local HVAC Technicians
Not sure what is wrong with your unit or whether it is worth repairing? Many homeowners start by comparing quotes from licensed HVAC technicians serving their local area for the specific cooling problem they are experiencing. Reviewing several local estimates side by side clarifies whether a repair or replacement is the better value and helps secure a fast appointment during peak season.
Cost figures in this guide are general estimates and may vary based on location, system type, and contractor. Always obtain a professional on-site assessment for an accurate quote.