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Portable Air Conditioner Not Blowing Cold Air? 8 Ways to Fix

A portable air conditioner that isn’t blowing cold air needs to be fixed. There are a variety of problems that might cause this issue, and identifying the right cause is key to getting the cool air flowing again.

If your portable AC is not blowing cold air, potential causes include:

  1. A temperature setting higher than the room temperature.
  2. Poor heat ventilation.
  3. Compressor hasn’t turned on yet.
  4. The filter is dirty.
  5. The fan power is set to LOW.
  6. Frozen cooling coils.
  7. A low refrigerant charge.
  8. Your AC is presenting an error code.

In this article, I’ll explain how to identify and fix each of these potential problems. Let’s get your AC blowing cool air again.

Portable Air Conditioner Not Blowing Cold Air

1. Temperature Setting is Higher than the Room Temperature

During the hot season, the room temperature somewhat determines the middle-temperature level of a cooling/heating system. 

As such, if you have a reverse cycle portable AC, setting the temperature above room temperature is telling the unit to heat while setting it lower gets the system cooling.

So, if your portable AC is not blowing cold air, you may have set the thermostat at a temperature higher than the room temperature (even just slightly), thereby telling your cooling unit to heat rather than cool. 

How to Fix

If your portable AC is not blowing cold air because it has a setting higher than the room temperature, perform these troubleshooting steps:

  1. Confirm that the thermostat is on COOL mode.
  2. Check the current room temperature.
  3. Lower your AC temperature setting one degree at a time until you can achieve the cooling level that suits your comfort. Remember that the closer the setting is to the room temperature mark, the more you save on cooling bills.

2. Poor Heat Ventilation

The function of an AC is to extract the heat from the room and send it outdoors while circulating cooled air in the room. 

Here’s how this works:

  • The fan extracts the hot and humid air from the room into the air conditioner.
  • The air is cooled down through the condensing process performed by the coils. 
  • The cool air is sent back into your room.
  • The moisture byproduct is gathered in a drain bucket.
  • The heat produced in the process is vented outside through a vent hose.

If this last action is not happening properly and the heat from the cooling process is being retained in and around the portable AC, the air will be warmed up and your portable AC won’t be blowing cold air.

How to Fix

If your portable AC is not blowing cold air due to improper venting, you should check your vent hose for these faults:

  • Check to see that the vent hose is sitting straight and has no bends preventing the hot air from being sent to the outdoors.
  • Ensure that the vent hose is no longer than 5 feet as longer vents delay the elimination of the hot air, making it stay longer around the portable cooling unit.
  • Check the vent hose for blockages that could be sending the hot air back to the cooling unit.
  • Check the vent hose for leaks at the joints (both at the AC and the window installation) or along the hose for any cracks or holes. These could be leaking hot air and re-warming the cooled air.

Note that poor venting can also cause damage to the compressor. If that happens, not only will your portable AC not produce any cold air, but it and may stall and stop working altogether.

3. Compressor Hasn’t Turned On Yet

Many air conditioners have a 5-minute delay after they turn on before the compressor starts running. This is meant to protect the system from the variation in temperature that comes with changing from a hot/warm state to a cool state.

This 5-minute delay also protects the compressor from the pressure created by the flow of refrigerant at the reverse valve.

How to Fix

If your portable AC compressor has not kicked on, ensure that you are not within the normal 5-minute delay period before concluding that your portable compressor is not blowing cold air. You should hear the kick-on sound of your compressor after the 5-minute delay.

If your compressor won’t kick on after this time, you could be facing bigger problems than just a kick-on delay. As a rule, problems with a portable AC compressor should be addressed by an expert HVAC technician.

4. Dirty Filters

Dirty AC filters can be a cause for almost every air conditioner problem. Why? Because air conditioners need good airflow to work properly.

Dirty portable AC filters limit the flow of air into your HVAC unit, which means they can block cool air from blowing out of your unit.

Clogged portable AC filters also make the cooling unit work harder than it should to keep you cool. The dirt on the filters also facilitates the buildup of dirt and/or mold in other parts of the AC, which causes components to malfunction and leads to high repair bills.

According to Energy Star, AC filters should be checked for dirt every month, especially when in heavy use.

How to Fix

If your portable AC is not blowing cold air due to dirty filters, you’ll need to change or clean them every 3 months as a rule of thumb. 

Here’s how you can clean your portable AC filter:

  1. Power off your portable AC.
  2. Remove the grid that covers the filter. You can also clean the grid while you are at it.
  3. Remove the air filter.
  4. Clean the filter with a mixture of warm water and a bit of dishwashing liquid and rinse them with clean water. If you are faithful to cleaning your filter every month, you might just need to dust them with a soft rag or blow off the dust with a vacuum attachment.
  5. Leave the filter out to dry completely.
  6. Replace the filter and the grid.
  7. Test to see if your portable AC begins to blow cold air as it should.

5. The Fan Power is Set to LOW

A portable AC fan distributes cool air in the room. How fast it does that is determined by the speed that you have set the fan on (LOW, MEDIUM, or HIGH).

If the amount of air being distributed is not meeting the cooling need of the room, it may seem like your portable AC is not blowing cold air. 

How to Fix

If your portable AC fan is set on LOW and does not blow cold air, change the setting to HIGH and see if that resolves that issue.

If your fan seems to have bigger problems than just a LOW setting, take a look at some of the other potential problems listed in this article.

6. Frozen Cooling Coils

If your portable AC has poor condensate draining and limited airflow, frost can cause the cooling coils (evaporator coils) to freeze. 

This happens if the low temperatures at the coils cause the moisture to condense. Your portable AC will then not blow cold air because airflow is altogether compromised.

If you suspect that the cooling coils in your portable AC are frozen and causing the portable AC not to cool, you have two choices to correct the issue:

  • Call an expert HVAC to check your cooling unit. Frozen evaporator coils often cause your AC to make a rattling sound similar to the one made by a fridge with frozen cooling coils. That noise is a good indicator your AC needs attention.

We can hasten the repair process for you if you fill the form at the bottom of the article and let us connect you with a reliable HVAC expert near you.

  • Check to confirm that your portable AC cooling coils are indeed frozen and troubleshoot following these steps:
  1. Power off your unit.
  2. Remove the grill covering the filter at the rear side of your portable AC.
  3. Remove the air filter.
  4. Inspect the top of the compartment to notice any ice buildup.
  5. If the cooling coils are frozen, leave your portable AC switched off and allow the frost to thaw. This could take up to a day. 

Alternatively, you can turn the AC to FAN mode to hasten the thawing process.

  1. Once the ice is fully melted, test your cooling unit to ensure that it resumes blowing cold air. If it does, your issue is sorted. If not, opt for our first solution: call an HVAC expert.

7. The Portable AC has a Low Refrigerant Charge

The refrigerant in air conditioners is the substance that flows through the cooling system to absorb and dispense heat from the cooling chamber. 

It is sent through the compressor and condenser and is converted from liquid to gas and back to liquid.  

If your portable AC was undercharged with refrigerant at the manufacturing process or has a leak, it will not have the recommended amount of refrigerant and will not complete the cooling process successfully.

One of the four signs that your portable AC is low on refrigerant is that it will not be blowing cold air because more heat is trapped in the cooling chamber. The other 3 problems are frozen refrigerant lines, longer cooling cycles, and high energy bills.

How to Fix

If your portable AC is not blowing cold air due to a low refrigerant charge, it will be hard for you to inspect the problem because you’ll need to dismantle the unit. I don’t recommend doing this yourself. Instead, you should call an HVAC professional to make the repairs for you.

To find an HVAC repair professional near you, just fill out the following form. We’ll connect you with the best HVAC services in your area, and they’ll reach out to you with quotes. You can choose the most affordable option and get your AC fixed without lifting a finger.

8. Your AC is Presenting an Error Code

Error codes can also cause a portable AC not blow cold air. One thing with error codes is that you need to decipher their meaning by checking the user manual that comes with your cooling unit.

Portable AC error codes that will cause your unit not to cool are often related to the working of the fan, the ambient temperature, the condensate drainage issues, and refrigerant issues, among others.

How to Fix

If your portable AC is not blowing cold air due to a displaying error code, check the error code in the user manual and according to the explanation, decide if the issue can be easily troubleshot or you need to call an HVAC expert. 

Remember that contacting an HVAC repair pro is always the most reliable solution for a portable AC that is not blowing cold air.


  • Nicole Sutton

    Nicole Sutton is an enthusiastic writer and knowledgeable contributor to She offers a plethora of knowledge to the platform, with a background in environmental science and a profound curiosity with all things connected to temperature regulation. Nicole's interesting and informative writings assist readers in making informed decisions about home heating, cooling, and climate control.

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