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A portable air conditioner outputs hot, humid air during the air cooling process, usually directed outside or somewhere through an exhaust hose. As this happens, it is normal for the hose to get warm. However, it can be worrying when a portable air conditioner exhaust gets hot beyond the ordinary.
There are various reasons why a portable AC exhaust hose may get too hot. This includes improper venting, incorrect BTUs, mold and dirt in the unit, frost build-up, and uncovered exhaust hoses. Let us look at the causes in detail and how to fix the problem.
Most Common Reasons Portable AC’s Hose Can Get Hot
1. Improper venting
All portable air conditioners require venting from which the created hot air can escape. Traditionally, venting is done through a window, but there are also more venting options for a portable air conditioner, even in a room without a window. However, the venting must be done correctly to work your AC unit effectively.
Proper venting means using a recommended venting kit for your AC unit. A perfect installation without flaws will also ensure all the heat is directed away from the room without stressing up your cooling system. Things like vent diameter, hose length, and closeness to the power output should be highly considered.
Any modification on the hose, including lengthening, changing the wideness, or using a longer hose, can affect how a portable air conditioner works. Doing so can cause the unit to operate inefficiently, heating up and sometimes damage to other internal parts.
2. Incorrect Size of AC unit
Choosing the right size of a portable air conditioner for your space is the most essential decision to make. Selecting a unit too small or too large affects the air cooling pattern not only in your room but also the performance of your AC unit itself.
Room air conditioners come with a range of BTU ratings, from most minor to the most powerful. A higher number of BTUs isn’t always the solution. Using a portable air conditioner with a BTU level higher than needed causes many fitful on-and-off cycles that make the air compressor overwork.
On the other hand, using a portable air conditioner with fewer BTUs than recommended for your room size will prevent you from attaining your desired comfort level. Additionally, the heat load will be too much for your portable air conditioner unit to handle. This will cause your AC unit to overheat due to continuous running.
Figuring out the size of your room is the first important step before you invest in an air conditioner, be it a portable air conditioner, window air conditioner, or a central air conditioner system. Measure and record every square footage of your room.
This information, together with other details such as the number of room occupants, presence of a kitchen, ceiling height, sunlight, and shade conditions of the room, can help you get the appropriate size of an AC unit. A cooling capacity calculator by Compact Appliance can help you get the actual value of BTUs required for your room.
See How Big an AC to get for 5000 Sq Ft Room
3. Frost Build-up
As the air conditioner extracts heat from indoor air, the surrounding moisture can condense and freeze on the coils. Heavy frost and ice buildup can cause a blockage affecting your air conditioner’s performance. You will notice abnormal heating of the hose vent and undesired temperatures in your home.
Frost build-up in your AC will also affect the rate of energy consumption by your machine. As it struggles to cool the air, more electricity units are used up. Other problems you will face with a frost build-up include refrigerant leaks, unexpected frequent shutdowns, and total system failure.
Refrigerant is an essential part of an air conditioner, it helps in filtering out heat from the air to provide the required cooling. Any damage to the coils and tubes can lead to refrigerant leaks. A portable air conditioner without a refrigerant does not cool the air as required.
Ensuring adequate airflow around your air conditioner is critical in preventing frost build-up. Evaporator and condenser coils heavily rely on a steady flow of airflow to function properly. Frequent checkups, repair of damaged parts, and thorough cleaning will prevent your air conditioner from suffocating.
4. Mold and Dirt in the Unit
Dust, mold, and mildew build-up in the unit can clog parts, including condenser coils, motors, and air filters. This will make your AC unit ineffective, and you can notice this through increased noise level, exhaust hose getting hot, odor, and sometimes the air conditioner not cooling at all.
Regular cleaning is an important maintenance step for a working air conditioner after prolonged storage. The carbon or HEPA filters should be cleaned and replaced as directed by the manufacturer. Condenser coils and air vent grills should be wiped clean. Ensure you have disconnected your AC unit from the power before you do the cleaning.
During the cooling process, the portable air conditioner collects water from the air in the room, which sometimes collects in a tank or pans fitted on the unit. This condensate needs to be removed regularly as it can lead to the growth of mold and mildew. It is also not good when a portable air conditioner fills with water quickly.
A musty smell in your air conditioner is a typical sign of mold. Inspect the drain pan, drain line, evaporator coils, and filter. If you discover discoloration, wear a mask and clean all reachable areas with vinegar or a cleaner made specifically for mold and mildew. Detachable parts, including hoses and the outer part of the unit, should also be cleaned with soapy water.
5. Unwrapped Exhaust Hose
The uncovered portable air conditioner exhaust hose can transmit conductive heat back into the room. It is also one of the reasons that you are not enjoying your desired comfort. Covering an exhaust hose with a suitable duct wrap will stop that radiant heat. Most AC exhaust hose covers are easy to install and can also be removed for washing.
We have seen that too much heat from your portable air conditioner exhaust hose is something that can be fixed. If you have tried any of the above methods and none is working, call a professional technician or request technical support from the product manufacturers.
HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.