3 Quicky Reasons Why Your Portable A/C Might Be Blowing Hot Air

A/C Blowing Hot Air

Sometimes, troubleshooting appliances at home can be daunting, especially with portable A/C units, because the guides from the service manual and manufacturer do not help much.

As its name suggests, many people think portable air conditioners are easy to use and troubleshooting, but it is not always the case.

For this reason, you need to know all the basics around it to troubleshoot its problem, and this is from blowing hot air to not working at all.

Why is my portable A/C blowing hot air? There can be several reasons, primarily because of the compressor not engaging and working, but the fan is. It is also due to the non-availability of cooling gas and kept in a hot condition.

This article will better understand how a portable air conditioner works and troubleshoot it when blowing hot air. If you plan to buy a portable A/C anytime soon, this short read is ideal for you.

How Portable Air Conditioners Work

Many people have misconceptions about portable air conditioners, and they think that it works by blowing cold air out of the unit and into your indoor spaces.

It is not true, and as a matter of fact, there is no such thing as cold at all. Instead, air conditioners, whether portable or not, pull in all the hot air around them and remove the heat from it.

After that, it will blow it back out, and this cycle repeats until the room reaches the set temperatures from your thermostat.

To be able to remove the heat, most air conditioners rely on a simple condensation and evaporation cycle, and the cycle works like this:

  1. The first cycle is with the refrigerant, and it is usually filled with Freon gas that is being compressed in the compressor. The added pressure then will cause the gas to heat up.

  2. The heated gas will then run through a series of coils where the heat will vanish. Eventually, the gas condenses into a liquid.

  3. The refrigerant in liquid form will now run through an expansion valve where it will evaporate again. Since the expansion valve’s pressure is relatively low, this will turn the gas into a cold state.

  4. The cold Freon gas will then run in another set of coils where it will absolve the heat from the room surrounding it. The fan is crucial because it is responsible for cooling the air throughout the room and the hot air back outside the room.

It might sound complicated, but it can pretty much be summarized into – hot air goes in, then the heat gets pulled out of it, and then it will be blown out again until the room is in the right temperature set.

A portable air conditioning unit has all the compressor and evaporator inside, unlike the central air conditioner, divided into two.

Why Is My Portable Air Conditioner Blowing Hot Air?

Before asking the “Why” and going deep into the mechanisms of your portable air conditioning unit (PAC), you need to consider checking the location of your PAC.

Ensure no obstructions in the front or the back of your PACs that hinder the airflow into your unit.

Check the exhaust hose and remove if there are any obstructions inside the hose.

It is also recommended to lightly vacuum your evaporator and condensing coils to remove any clogs in them.

Fan Motor Issues

If doing all the tasks mentioned above does not fix the issue, then it is most likely that the cause of all the hot air is due to faulty mechanisms.

It can be either that the motor fan may be blown, the compressor might be malfunctioning, or the coolant might run out.

If the problem is related to the fan motor, you do not have to hire a professional as it is possible to change the motor by yourself.

All you have to do is find the motor that matches your portable air conditioner model, and there are many guides available only to replace it properly.

When the fan motor creates the problem, you need to replace it as soon as possible to burn out your compressor.

Compressor Issues

If your problem has something to do with the compressor, the chances are that the compressor is seized and pulling on locked motor amperage.

It means that the compressor tripped on internal overload and the only solution for malfunctioning compression is to buy a new one and then replace it.

The only issue you will be facing is that the compressor is usually two-thirds of the whole portable air conditioner unit value.

You might need to sell your old PAC unit to salvage places or dump it out and buy a new one.

If the compressor does not work due to some damaged condenser coils or the cooling fan is broken, you can either replace all these components or switch your unit to a new one.

It is because these scenarios can eventually lead to some overheating issues, so you might need to be on the lookout.

Lack Of Refrigerant Or Coolant

If your portable air conditioning unit has run out of refrigerant or coolant, add some into your unit.

You can look for a valve that is typically located on the suction side of your PAC unit.

Gauges are usually hooked up and show readings for the system, but you need to be careful to use the refrigerant that is the one your unit needs.

It is worth mentioning that refrigerants are expensive, and if you do not want to spend money on refrigerants, you may choose to purchase a new unit instead.

Overall, if you have tried everything on this list and the unit is still not blowing cold air, you can always call your electrician or purchase a new one.

Fixing A Portable A/C That’s Not Cooling

The first rule of troubleshooting is always to have a clear definition of the problem.

Ask yourself what you are expecting to happen and what is happening instead.

Suppose you can answer these questions, you will be able to point out the right solution.

Here, you can see that the troubleshooting steps have been split up into two sections.

The first one is the basic troubleshooting for significant problems that keep your portable air conditioning from working at all.

The second one is the performance troubleshooting for many portable air conditioners that do not cool as you need them.

Basic Troubleshooting

When it comes to basic troubleshooting, the first step is to power the unit and make sure your air conditioner gets the power it needs.

If the lights and fan don’t power up when you press the power button, find out why the unit is not getting power in the first place.

  1. The first option is to check the air conditioner plug, and there should be a test and reset button for your built-in breaker. Press this test button to trip the breaker and then push firmly on the reset button and try to turn it back on again.

  2. If the unit still doesn’t power up, you need to check if there is enough power to the outlet. You can get a night light or a reading lamp that can help with this step for illumination. If you’re not getting power to the outlet, make sure that a wall switch is not turned off and check all the breakers in your household electrical panel.

Another thing to look into is the mode setting, as most air conditioners have at least three settings on their control – cool, fan, and dry. If you need to have a cool air blowing, you need to make sure that the PAC is set to cool more and turn the air conditioner thermostat down. It will ensure that the system will activate the cool setting. Just be mindful that it takes a few minutes to power up before the cooling process starts.

Finally, look for some fan obstruction and check if any fan grilles have something in them.

You can use a flashlight into the openings to check for debris or any matter that is stopping the fans from moving. Also, there is always a warning indicator to tell you if there is something wrong with your unit.

If your A/C randomly shuts down or flashes or beeps, an internal water tank is full. It would help if you wheeled the air conditioner somewhere where you can drain out the water.

Troubleshooting Poor Performance

If you own a portable air conditioner that turns on but is not precisely performing as it should, you might need to look at some poor performance troubleshooting.

Once you are sure that you set the cooling mode, you need to wait for the compressor to kick in, as it usually takes about 60 to 90 seconds.

Go to your PAC and check if the temperature is coming out of the air flowing into the evaporator coil and to the top of the unit.

If you have an air conditioning unit that is not blowing cold air, you can try the following steps to see if your PAC is performing at its best:

  1. Clean all your filters and coils, and if you have not cleaned your PAC in a while, it is 100% advisable. Take out all your filters and run a vacuum hose with a soft brush attachment over the coils’ fins.

  2. While you are clearing and checking your portable air conditioner filter, you need to take a good look at the top coil, which is usually the evaporator coil. Look if there is any frost building up and stopping your airflow. It can be an issue because it will restrict any airflow in the process.

    The build-up will only melt into the internal reservoir for quite some time, but running the unit in fan mode will help speed this up.

  3. Last but not least is to check your exhaust for any kinks or blockage along the way. If the hot air cannot get out of your vent, it is most likely that the air conditioner can’t cool your indoor spaces.

Improving Efficiency

There are also some instances where your A/C is blowing cold air out of the top vent, but your indoor space is still not getting cold.

It might be that your room is too hot or too large for the heat capacity to be able to cool your air conditioner.

It would help if you remembered that portable air conditioners have their limit, and they can only cool the room that it is advertised into to moderate the outdoor heat.

If it is above 95°F outside, your PAC will have difficulties keeping up, especially if it is one of those single-hose designs.

But, this is not the end. You are still able to take the following steps to boost and improve the efficiency of your PAC during hot days:

  1. Always make it a habit to straighten your vent air hose and keep your portable air conditioner in a situation where the vent hose is straight and short. This way, it will get the heat out more efficiently, and be mindful that tiger bends are worse than a longer hose.

  2. Check for leaks in your air hose. It is essential because air traveling through the PAC vent hose carries all the heat you are trying to eradicate from your home. So ensure that none of it leaks back into your room, or your PAC has to work double-time, and it might be useless at this point.

  3. Check if you have leaked on your window brackets as air leaking out of the hose joint or leaking in from outside will only decrease your PACs’ performance.

  4. Insulation is probably the key to making sure your portable air conditioner is working, and you need to make sure that your windows are properly insulated. Close your doors and windows because if hot air leaks into the room from the outside, your PACs won’t be able to keep up.

How To Vent Your Portable Air Conditioner

Portable air conditioners are the type of air conditioning units that can be more from one place to another.

They are known to be self-contained systems that do not necessarily require many installations but require venting via a wall or a window.

You need to consider this so you can avoid a lot of performance issues.

Why is Venting Important?

Venting is vital for many portable air conditioners because they are the ones responsible for extracting hot air.

If you wish your air conditioning system to cool your indoor spaces effectively, you have to let the hot air go outside without any blockage.

When you first purchase your PAC, the venting kit will always be included, so you won’t have to worry about buying it. Portable air conditioning units can be vented through a wall, window, ceiling, or even a door.

As mentioned above, when you buy a portable air conditioner, a venting kit is usually available, and it must be installed for the unit to work correctly.

Although there are various sizes and styles for portable air conditioners, the venting steps always remain the same.

  1. The first step to implement is to decide where you want to vent your portable air conditioner. Usually, many people put their portable air conditioning units out of a sliding window while others put theirs out of a drop ceiling or a wall.

  2. Connect your A/C to the exhaust connector and then the exhaust connector to the exhaust hose. Then you should connect the venting window kit.

  3. You can install a sliding window kit in the window by sliding it to the right height and then shutting the window on the kit. If required, you can make the kit and then cut it down to fit your opening correctly, and then your portable air conditioner is ready to use.

A few pointers to make sure that you keep the exhaust hose very straight if you are using a venting system.

It is not recommended to increase the exhaust hose’s length, and using an extension cord with a portable air conditioner is a big no.

Always remember that venting instructions also come with different instructions depending on the unit.

Most importantly, it would help if you remembered to follow the instructions provided by your air conditioner. By adequately venting the unit, your portable air conditioner will last you for many years.


In conclusion, if your portable air conditioning unit is not behaving as it should, the chances are that there is something wrong with it.

You might need to troubleshoot it by using basic troubleshooting or through low-performance analysis.

Fixing a portable air conditioning unit is very important because if you didn’t look into it, you jeopardize your air quality and your portable air conditioning unit.

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