Air Conditioner Running But Not Lowering Temperature | Troubleshooting Tips

Why is my air conditioner not cooling the house?

Unfortunately, there are many reasons why you have AC running but not cooling your home. In fact, the issue could be found with your thermostat, filter, or with another critical system component.

While you can always call an AC service provider to diagnose and treat the issue, there are a few troubleshooting tips you can try first.

These easy-to-follow tips include:

Check the thermostat

If you have HVAC running but not cooling, the first step is to check your thermostat. First things first, make sure this device is set to cool. If it is, check the temperature setting to see if anyone made an adjustment. If you recently had AC service, something could have been changed by mistake. In the event the thermostat is set to off, switch it to heat before changing it back to cool. After waiting a few minutes until you hear the cooling unit kick on, head to your registers to check for any cold air blowing out. If you feel the cold, the problem is fixed! If you don’t, move onto the next step.

Examine the air filter

While it may sound like a surprise, a dirty air filter can significantly impact your cooling system. That said, it’s best to consistently check to see if these are dirty, then replace them if needed. While your air filter’s job is to trap dirt, dust, and other airborne particles, they can’t work properly if they’re filled with debris. As an air filter helps to keep these particles out of your home, they also aid in preventing this debris from infiltrating your system’s components.



If you have central AC not blowing cold air, take a look at your air filter. But before checking it, make sure your system is powered off. From there, remove the filter and take a look. If everything checks out and the filter looks clean, proceed to the next troubleshooting tip.

Look at the condenser

A central air conditioning unit typically has an outdoor condenser unit. The outside of this unit usually features an outdoor coil that wraps around the condenser. This coil has multiple “fins” that are spaced close to one another. If you're experiencing AC not cooling while the system is powered on, you could have a clogged or blocked coil. Unfortunately, a wide variety of debris can find its way into this equipment, including grass, dirt, and other contaminants. This can result in a serious clog, which can lead to a system malfunction. While this can cause your unit to blow warm air instead of cold air, it can also decrease your energy efficiency and even result in a system shutdown.

To troubleshoot the issue, check the condenser and clean away any debris. This area can be cleaned by a vacuum with a brush attachment, or try using a hose to gently wipe away any dirt and grime. Still dealing with AC running but not cooling? If so, it may be time to call a professional for service.

Frozen evaporator coil

On the indoor portion of your AC unit, you’ll find an evaporator coil. When warm air passes through this coil, heat and humidity are removed from the air, then much cooler, conditioned air is then pumped back into your home. But on some occasions, this coil can freeze, which can result in your central AC not blowing cold air.

Look out for these signs of a frozen evaporator coil:



• Poor, ineffective cooling
• Increase in energy bills
• Frost accumulating on the copper refrigerant tubing
• Excessive condensate drainage

Unfortunately, fixing a frozen evaporator problem can be very challenging. That said, you’ll want to call a licensed, experienced HVAC technician to solve the issue. If you have an air conditioner not cooling, these professionals can sometimes fix the problem within minutes.

Leaking refrigerant

In order for your AC unit to work properly, refrigerant is needed. This is a chemical that flows through both your indoor and outdoor systems. The primary goal of refrigerant is to extract the heat and humidity from the indoor air before it goes outside. If you have a refrigerant leak, this can result in poor system performance and even a complete unit shutdown.

While it may sound simple to check and fix your refrigerant issue, this is another job for a dependable HVAC technician. They can easily check your refrigerant levels and make any necessary adjustments.

Leaky ducts

Your ducts are another location where a leak may be present. As your air ducts are used to guide conditioned air throughout your home, a leak can throw a kink in the process. As many AC ducts are found in the attic, some of that warm air can travel into your ductwork, leading to an increase in indoor temps.

As repairing leaky ducts can be a serious hassle, call a professional AC service provider for assistance.

If your air conditioner is working but not cooling, try these tips to restore cooling comfort to your home!