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10 Reasons Your Portable AC Blows Hot Air (& Fixes)

Reasons Why Your Portable Ac Blows Hot Air

Forget about the old days when you had to install a mini split AC or a window unit for cooling small rooms because portable air conditioners can do the job better.

These self-contained moveable devices are an excellent option for cooling smaller spaces.

The primary purpose of a portable air conditioner is to provide a cool breeze and lower the temperature of your room in no time.

However, sometimes your PAC might work differently. You will notice that your portable device is blowing hot air instead of cold ones, which is worrisome.


Several reasons your portable air conditioner might blow hot air instead of a cooling breeze. The most common ones are:

  1. Low level of refrigerant
  2. Faulty compressor
  3. Clogged cooling coils

If you have a faulty compressor, it is better to get it replaced or change the whole appliance, as compressors are expensive, and it might cost you more to take it to the repair show after every few months.

Some causes are easy to detect and fix with DIY steps. However, getting professional help is always advisable.

Are you worried about your portable air conditioner’s performance? Read further to know some insightful reasons for it to blow hot air and its easy fixes.

10 Reasons for Portable Air Conditioners To Blow Hot Air

Reasons For Portable Air Conditioners To Blow Hot Air

Before we dig into the reasons causing a malfunction in your appliance, it is essential to know the working of a PAC. All the air conditioners work on the same principle. There are mainly four components that help in providing cold air.

  1. Compressor
  2. Refrigerant
  3. Cooling coils
  4. Exhaust Fan

The AC compressor compresses the refrigerant and turns it into liquid from the gas. This process is exothermic, and the refrigerant releases heat that escapes the unit via an exhaust fan.

The liquid refrigerant then travels to the expansion valve, turning it back into gas. The process is endothermic and releases chilly air that cools down the coils.

Once the hot air passes through the cooling coils, their temperature changes, and that’s how we receive the refreshing breeze from our AC.

So, now that you have understood the working of an AC, let’s look at its possible reasons and fixes.

1. Low Refrigerant

Low Refrigerant

PAC uses a refrigerant that helps cool down the cooling coils.

If your AC doesn’t have enough freon (refrigerant) levels, it won’t compress and release cool air to lower the coil’s temperature.


The main reason why your AC can have low refrigerant levels is having leaked refrigerant lines within the unit.

These closed lines require an HVAC professional to fix the leak and refill the refrigerant.

2. Faulty Compressor

Faulty Compressor

An AC compressor is the most critical component of the appliance.

If the compressor is not completely compressing the refrigerant, it won’t expand enough to produce a cool temperature for the coils resulting in hot air coming out of the unit.


Compressors are pretty expensive and cost around 2/3 of the total PAC price.

Instead of fixing or replacing it, it is better to change the whole system and get a new one. Buying a new compressor or getting it fixed time after time will only cost you more money.

3. Damaged Exhaust Hose

Damaged Exhaust Hose

Portable air conditioners have exhaust hose that helps expel the hot air outside the window.

If the exhaust hose is bent, damaged, or clogged, it won’t remove the hot air outside efficiently, resulting in poor cooling inside the room.


Thoroughly check the exhaust hose; replace it immediately if you find any leakage or damage.

It is also good to use the window fix kit while fixing your exhaust hose outside the window, which will keep the hose in its place, and won’t let any warm air return to the room.

4. Bad Control Board

All the air conditioners have control boards that receive information from the thermostat and make decision-based on the given data.

If you notice your compressor turns off intermittently, it can be due to a fault in the control board resulting in hot air.

The AC board can get damaged for several reasons, such as a short circuit or overuse.


It is relatively easy to replace and repair if you can track a problem with your control board, like a fuse or a damaged thermostat.

However, it is better to contact a professional and check this properly.

5. Check the AC Settings

Check The Ac Settings

It sounds basic, but quite possible that you do not have the correct settings on your AC, causing it to blow off hot air.

Check if your AC is set on the cool mode and your thermostat is set to a temperature lower than the room temperature.


Carefully read the AC manual and see how to set your device to provide optimal performance.

6. Clogged Air Filters

Clogged Air Filters

Before I discuss the air filters, let me make one thing clear. Dirty air filters do not cause the AC to blow off hot air. It will only prevent airflow, and you won’t get the maximum air from the AC.

On the other hand, clogged or blocked air filters are the culprit for hot air coming out of your appliance.

Air conditioners are required to maintain adequate airflow to function correctly.

If your air filters are clogged, the airflow will reduce drastically, and all the other AC components will start working more to compensate for it, resulting in poor performance.


You can easily replace the clogged air filters and get things working again.

7. Dirty Evaporator Coils

Dirty Evaporator Coils

Evaporator coils are an essential element for providing cool air.

If they are blocked, it won’t let the air pass through, resulting in hot air.


If you can access the evaporator coils, clean them with a soft brush. However, be careful as coils are very fragile, and you can damage them if handled carelessly.

You can also ask a professional to do the job for you.

8. Faulty Thermostat

Faulty Thermostat

The thermostat helps in regulating the device temperature in your home. If the PAC thermostat is faulty, it won’t understand the desired temperature resulting in either AC turning off before the desired temperature or not turning off.

Getting hot air out of your AC means your appliance turns off before the desired temperature.


You can ask the professional to check the thermostat and get it replaced.

It is inexpensive and doesn’t require much effort.

9. Broken Blower Wheel

Broken Blower Wheel

The blower wheel is the critical component that blows the air over evaporator coils and helps them to cool down.

The fan is driven by a motor that sucks the air from the environment and cools its temperature down.

Sometimes if a sharp object comes in contact with the blower fan, it can damage its blades resulting in hot air coming out from your portable air conditioner.


Before jumping to a conclusion, checking the blower fans’ working is essential. Remove the hose vent and turn on your AC. If you see the blower fan rotating correctly, it is intact and has no issue.

However, if you notice the fan is blocked or not moving correctly, you can easily replace it.

10. Tilted AC Position

Tilted Ac Position

If you have stored your air conditioner somewhere in a tilted position, it will most likely blow hot air once it starts. The reason is an accumulation of refrigerant on one side.

When PAC is kept in a tilted position for longer, the refrigerant accumulates at one side and doesn’t compress efficiently, resulting in poor performance.


It is recommended to use your AC once every season to know if everything works properly.

Similarly, if you have kept your AC tilted, give it some time to settle before you start operating it.


Portable AC is a useful invention that can move easily from one place to another while keeping your room cool.

However, for several reasons, it can malfunction and start blowing hot air resulting in an uncomfortable experience.

If you can pinpoint the reason for the malfunction, it is better to get it fixed as soon as possible or get professional help before it’s too late.

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