Why is my AC not cooling my house?

Author: Giovanna Wunsch Sr.  |  Last update: Friday, February 6, 2026

If your AC is running but not cooling, it could be due to a dirty air filter, incorrect thermostat settings, a malfunctioning thermostat, a refrigerant leak, dirty condenser coils, blocked vents or ducts, a faulty compressor, frozen evaporator coils, or electrical issues.

Why is my air conditioner running but not cooling the house?

There are a number of reasons why your air conditioner might be running but not cooling. It could be an issue with the thermostat, the compressor, or the evaporator coils. Or, it could simply be clogged with dust and debris, which is preventing it from working properly.

Should I turn off AC if it's not cooling?

Switch it off. There's no need to be using it if it's not cooling so it's just a waste of electricity. And in some cases such as a freeze up it'll make the technician have to stay longer to fix it because he would have to wait for the ice to melt.

How do I fix my AC not blowing cold air in my house?

Start with the simple things. Replace the air filter, and clean the condenser coils. Evaporator coils are a lot more difficult to inspect and clean, but if the air filter has always been in place and there are no leaks that would cause unfiltered air to enter the air handler - the evap coil is probably clean enough.

Why is my AC not cooling below 72?

Many factors can cause this issue, including clogged filters, refrigerant leaks and the wrong unit size. While it's possible to troubleshoot it yourself, it is best to contact an HVAC professional for your AC problems.

#1 AC Problem With Central Air Conditioning Not Cooling

Why is my AC not reaching set temperature?

One possible reason your AC is not reaching the set temperature is that the thermostat could be dirty. If dirt, dust, or other debris has accumulated within the thermostat box, it can cause the wires to heat up or other issues. Thermostats are cleaned during routine HVAC maintenance to help prevent this from happening.

How long should it take to cool a house from 80 to 72?

Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.

Is it normal for AC to not cool in summer?

If your air conditioner isn't keeping up with the heat, your air filter may be to blame. A dirty air filter can obstruct the airflow path through the unit. Using a dirty air filter can also cause less energy efficiency and more costly utility bills.

How do I get my AC cold again?

Why Is My AC Not Blowing Cold Air? Easy Fix
  1. Introduction. ...
  2. Check the AC unit to make sure it's not running on low refrigerant. ...
  3. Look for debris in the condenser, which is part of the system that pushes air through the vents. ...
  4. If you have a coil unit, check your airflow. ...
  5. Check your filters and replace them if necessary.

What is the first thing to check when the AC stops working?

Check these issues when the unit won't kick on: Check the thermostat and adjust the settings if it isn't set to Cool and an appropriate temperature setting to call for cooling. Examine the house circuit breakers for the AC unit and reset any tripped breakers. Check the air filter and replace the filter if it's dirty.

Why is my AC struggling to keep my house cool?

Proper airflow is crucial for an AC system to cool your home efficiently. Several factors can compromise airflow, including blocked or obstructed vents, closed or incorrectly adjusted dampers, and dirty or obstructed evaporator coils. These issues restrict the air's flow, reducing the system's cooling capacity.

How do I reset my central AC not blowing cold air?

Use these tips to reset an air conditioner using the reset button:
  1. Turn your thermostat to the “off” setting.
  2. Turn off the circuit breaker that powers your AC.
  3. Press and hold the reset button for three to five seconds.
  4. Restore power to your AC by flicking the circuit breaker back on.

How often should I change my AC filter?

How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.

Why is my house still hot but the AC is working?

Insufficient Insulation and Air Leaks

If you have gaps on the sides of your windows and doors, cold air might be leaking out, and hot air might be seeping in. A lack of insulation in your attic and throughout your home can also cause cold air to leave your home quickly.

Where is the reset button on an AC unit?

Power down your AC: Turn off your AC unit and unplug it from the power source. This will ensure that you stay safe while working on the unit. Locate the reset button: Most air conditioning units have a reset button located near the outside unit. It is usually a small button located inside a small hole.

How to check if AC is cooling properly?

Ways To Check If Your AC Is Working Properly
  1. Check the Air Flow. If your AC is trying to cool a room that continues to stay excessively warm, it may not getting enough airflow through the vents. ...
  2. Check the Thermostat. ...
  3. Check for Refrigerant Leaks. ...
  4. Check the Smart Settings. ...
  5. Check the Outdoor Unit.

How do I fix my AC not getting cold?

First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.

How to know if refrigerant is low?

Warning Signs of Low Refrigerant in Your AC or Heat Pump
  1. Weak Airflow or Warm Air Blowing from Vents. ...
  2. Poor Cooling Performance. ...
  3. Constant Cycling On and Off. ...
  4. Ice Buildup on Refrigerant Lines or Evaporator Coil. ...
  5. Hissing or Bubbling Noises.

How to unclog an AC drain line?

To unclog an AC drain line, turn off the power to the unit. Locate the drain line and use a wet/dry vacuum to suck out the clog. Flush the line with water using a garden hose or cup of water. Check and clean the drain pan under the indoor unit.

Should I run my AC if it's not cooling?

Yes, you should turn off your AC if it's not cooling. Continuing to run a malfunctioning AC can strain the compressor and other components, leading to more severe and costly repairs.

Why is my AC not going below 78?

Key Takeaways. Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.

How cool should my house be if it's 110 outside?

For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.

How cool should my house be if its 90 outside?

If it's 90 degrees outside, most people would set their AC to a perfectly comfortable temperature of 68-72°F.

Why is my AC taking so long to cool my house?

Dirt, dust mites, pet dander, debris, and other buildup can get trapped in your AC filter. Once this buildup reaches a certain point, it reduces your air conditioner's efficiency. This makes the unit work harder to cool down your home, which is why it takes longer to reach the desired temperature.

How long should AC take to drop 2 degrees?

On average, expect about one hour per degree change to meet what you've set on the thermostat during normal AC running hours. Think of it as trying to turn back a tide with a spoon—it'll happen but at nature's pace.

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