Portable Air Conditioner Exhaust Hose Getting Hot? Here’s What to Do

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Is your portable AC’s hose getting hot? In most cases, a little bit of warmth is okay. 

But if your portable AC’s exhaust hose is getting excessively hot, that could mean trouble. In most cases, it’s an indication of an issue with the installation or operation of the air conditioner.

In this article, I’ll discuss a few reasons why your portable AC’s exhaust hose is getting hot. I’ll also provide a few tips for keeping the temperature of the exhaust hose (and the temperature of your space) much cooler!

Check for low airflow in portable air conditioner

Low airflow through your portable AC will cause the exhaust hose to get hot. Why does that happen? The exhaust hose is used to discharge heat from the portable AC. So if your portable AC doesn’t have enough airflow through its exhaust hose, then heat won’t be able to flow outside properly.

So what can you do to increase airflow through your portable AC’s exhaust hose?

The first thing you should check is that the exhaust hose does not have any blockage. Check that there is nothing blocking the discharge of the hose—where it connects to the outside of your home. Sometimes plants, leaves, and even bird nests can block the exhaust hose discharge.

Another thing to check is the exhaust filter in the portable AC. The exhaust filter catches dust and debris—that way the exhaust hose doesn’t get clogged up. The exhaust filter in most portable ACs is a reusable, mesh-type filter that can be washed out with water. To clean the filter, remove it from the AC and spray it out with water to remove the dust. Allow the air filter to fully dry before placing it back into the AC.

Vent the portable air conditioner correctly

The next thing that you should check is for kinks and twists in the exhaust hose. If the exhaust hose has too many kinks, then air won’t be able to flow out of it. 

When setting up the exhaust hose, you need to avoid bending it as much as possible. Ideally, you want the exhaust hose to be in a smooth, straight shape from the AC to the exhaust vent. If you need to bend the exhaust hose for any reason, use a smooth gradual bend instead of a tight abrupt bend.

You’ll also need to keep the exhaust hose length as short as possible. This will help with airflow. Collapse the exhaust hose so there is no excess length between the AC and the exhaust vent.

Portable AC is too small for the space

Another reason why your portable AC’s exhaust hose gets too hot is that it is undersized for the space that you are trying to cool.

If a portable AC is undersized, then it will be constantly on, and never bring the temperature in the space down to a comfortable level. Because of this, the portable AC is always running at full load. The AC’s exhaust air is hotter than it would normally be if the portable AC is cooling a space at a comfortable temperature.

If your portable AC is too small for the space, then you can try to reduce the size of the space that you’re trying to cool. Shut all doors to the space to prevent warm air from infiltrating the space. Shut all windows and blinds to keep outside air and sunlight from warming up your space.

Besides that, the only thing you can do if your portable AC is too small for a space is to get a larger one.

Portable air conditioner exhaust hose needs to be insulated

In most cases, if your portable AC’s exhaust hose is hot, it’s due to one of the reasons above.

However, if everything else checks out and your exhaust hose is still hot, then you can just insulate the exhaust hose.

Insulating the exhaust hose ensures that minimal amounts of heat are transferred back into your space from the hose.

Fortunately, you don’t need to come up with a DIY solution to insulate an exhaust hose. There are many off-the-shelf exhaust hose insulation products available out there. So all you need to do is wrap your portable AC’s exhaust hose with a purpose-fitted solution.

My Pick
Insulated Hose Cover for Portable Air Conditioners (Universal)

This insulated cover fits over most portable air conditioner exhaust hoses. Slip it over the hose section and it will help keep the heat outside of your home.

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Hi, my name is Trey Lewis and I’m the founder and chief editor at HVAC Training Shop. My goal for this website is to help homeowners troubleshoot and maintain their home’s HVAC systems. Whether it’s changing an air filter, troubleshooting a blower motor, or just buying a new humidifier, I want to make sure that you’re covered.

10 thoughts on “Portable Air Conditioner Exhaust Hose Getting Hot? Here’s What to Do”

    • Hi David,

      I do not recommend using an additional fan at the outlet of the exhaust hose. If you do so, you run the risk of running the AC outside of its design parameters and may cause damage to the unit.

      Instead of using an additional fan, ensure that there are no restrictions to airflow out of the exhaust hose. Be sure that the exhaust hose doesn’t have excessive bends or kinks, and that the discharge of the exhaust is free and clear of obstructions.

      Hope this helps,

  1. Hi Trey,

    We have a finished attic with a crawl space behind a drywall knee wall. I cut a 6″ hole in the knee wall and put an aluminum coupler in the hole. I connected the AC hose to the coupler and the hose runs 1 foot. In the crawl space, I connected 6″ aluminum flex hose to the coupler and then ran it to the soffit vent. I attached the hose so that it stays flush with the soffit vent. Does this sound ok? I do notice that the aluminum coupler is hot to the touch (like a hot water line temperature). Should I be concerned?

  2. I put a Dundas Jafine Flexible Vinyl Duct, 4″ by 20′ to my Portable Air conditioner and it’s getting hot. Will that be harmful.

    • Hi Carmelita,

      20′ is too long for a portable air conditioner hose. The hot air needs to be able to make it outside and with a long hose, there is too much resistance for all of the air to travel that distance.

      Hope this helps,


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