Why did my portable AC stop blowing cold air?

Author: Keven O'Kon  |  Last update: Sunday, July 27, 2025

If your Portable Air Conditioner is not blowing cold air please check the following: check that the unit temperature setting is lower than the room temperature; check that the fan is blowing warm air from the back of the unit; check that you hear the compressor kick on after start up (could be a 3 minutes delay);

How to fix portable AC unit not blowing cold air?

If the portable air conditioner is running, but is not blowing cold air:
  1. Clean the filter. ...
  2. Confirm there is ample space around the unit, and that there is nothing obstructing the air flow around the intake. ...
  3. Verify your unit is in Cool mode.

Why is my AC suddenly not blowing cold air?

A dirty air filter can block airflow and reduce cooling to your home. In more extreme cases it can cause the system to shut down completely. If your thermostat checks out and you still don't have cool air, locate your system's air filter, turn the system off, remove the filter and inspect.

How do I reset my portable air conditioner?

Power Off and Unplug
  1. Turn off the air conditioner using the power button or switch.
  2. Unplug the unit from its power source.
  3. Wait a few minutes for the system to reset.
  4. Locate the Reset Button:
  5. Find the reset button, usually small and red, often located on the control or front panel.
  6. Press and Hold Reset:

How can I make my portable AC colder?

To ensure that your portable air conditioner works effectively, it's essential to seal any gaps or cracks around windows and doors. These openings allow warm air from outside to enter your space, making it harder for the air conditioner to cool the room efficiently.

Why is my portable AC unit not blowing cold air?

Why doesn't my portable AC cool the room as much anymore?

A blocked air outlet or intake could be causing the trouble. Check that the outlet/intake is free from blockage by furniture or any other objects that could be in their way. In rooms with large or multiple windows, sunlight streaming in can decrease the portable AC's cooling effectiveness.

How can I make my AC cold again?

To make sure your air conditioner (AC) is blowing cold air again, you can follow the pointers mentioned below:
  1. Fix 1: Check Out the Thermostat. ...
  2. Fix 2: Take a Look at the Filters and Get Them Replace. ...
  3. Fix 3: Check the Condenser for Debris. ...
  4. Fix 4: Air Compressor Filled with Dirt. ...
  5. Fix 5: Take a Look at the Indoor Fan.

Does my portable air conditioner need to be drained?

Yes. The water is accumulated in an internal drain pan. This water is evaporated and sent out the exhaust hose in the form of water vapor. Occassionally, the unit will need to be drained in humid environments.

Where is the AC reset button located?

In AC systems, the air conditioner reset button is on the outside unit's lower edge, typically close to the ground. Some models have the reset button located behind the service panel, which may require tools to remove. Reset buttons are usually red or yellow with a clear “reset” label.

How do I know if my portable air conditioner is frozen?

A few telltale signs of a frozen AC unit include:
  1. Your AC system isn't reaching the desired thermostat setting.
  2. The air blasting from the air registers feels warm.
  3. Your electric bill is higher than usual.
  4. Water leaking around the AC.
  5. Hissing or bubbling noise.
  6. Condensation and moisture around the air handler.

Why did my AC randomly stop blowing 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.

Should I turn off AC if not blowing cold air?

Turning off your AC when it's not cooling is more than a precaution; it's a necessary first step in troubleshooting and protecting your system from further damage. By understanding when to perform simple checks and when to call in the experts, you ensure your air conditioner remains a reliable refuge from the heat.

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 do I fix my AC that isn't blowing cold air?

Check your filters and replace them if necessary.

If your filter is dirty or clogged, it may be the reason why your AC isn't blowing cold air. Dirty filters can cause a restriction in the airflow. To check if this is the case, remove the filter and inspect it for dirt.

How long does a portable AC last?

Here's how long some of the most common types of AC last:

Portable AC — 5-10 years. Residential single whole-home AC unit — 15 years. Central air-source heat pumps — 15 years (and up to 20–25 years if well-maintained and in a well insulated home) Ductless mini-split AC systems (heat pumps) — 20 years.

Why is my compressor not kicking on my portable AC?

When a portable AC compressor doesn't turn on, it's crucial to inspect the thermostat. Start by adjusting the thermostat settings to ensure they are at the appropriate cooling levels. If the compressor still doesn't turn on, a faulty thermostat may need to be replaced.

How do I force restart my AC?

Use the Reset Button on AC Unit

Don't worry; the reset button might be able to solve the issue after a sudden disconnection or power outage. You can press the “Reset” button on the air conditioning unit, often shown as a small red button, to bring your air conditioning unit back to life.

How to reset portable air conditioner without remote?

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 long does it take for AC to reset?

Once you locate it, turn the knob to the off position and leave it for at least 30 minutes up to an hour. This will allow the electrically operated components in the AC to reset.

Why is my portable AC not cooling the room?

A portable AC unit can fail to properly cool off your space if it is not powerful enough, the room is not properly sealed, or the unit is dirty. Unfortunately, units love to act up on the hottest days of the year.

Is it okay to run a portable air conditioner continuously?

Generally, portable air conditioners can run continuously for 8 to 12 hours, depending on the factors mentioned above. However, it is essential to give your unit some rest to prevent overheating and ensure its longevity. Experts recommend turning off the unit for 15-20 minutes every 3-4 hours of continuous operation.

How to unclog a portable AC drain line?

How to Unclog Your AC Drain Lines in 9 Steps
  1. Turn Off Your Air Conditioner. ...
  2. Locate the Drain Line Pipe. ...
  3. Remove the Cap From the Pipe. ...
  4. Inspect the Drain Line Pipe. ...
  5. Unclog the Drain Line Pipe. ...
  6. Pour in Vinegar. ...
  7. Use a Wet/Dry Vacuum Cleaner. ...
  8. Reconnect the Cap to the Drain Line Pipe.

What causes AC to stop blowing cold?

If your central AC is not blowing cold air, the refrigerant may be the problem. The unit could be running low and need additional refrigerant added. The most likely cause of this is a leak. A leak not only keeps the AC unit from cooling properly, but also it can cause other issues within the home.

Will adding freon make AC colder?

If you don't have enough refrigerant, it won't be able to cool the air. But if you have too much, the pressure will be too high for the refrigerant to boil or for the compressor to work. Which means the system won't cool at all, and you'll still be left with hot air.

How to check refrigerant level in AC?

Steps for Checking Refrigerant Levels
  1. Turn Off the AC and Remove the Cover. Turn off the AC unit and remove the cover to access the refrigerant level gauge or gauges.
  2. Locate and Remove the Access Panel. ...
  3. Attach Refrigerant Pressure Gauges. ...
  4. Interpret Pressure Levels. ...
  5. Add Refrigerant (if Necessary)

Previous article
Can I leave my stove on all night?
Next article
What happens if I put a large ceiling fan in a small room?