Last Updated on March 12, 2023
When you are in your apartment or RV you have to carefully adjust and organize things to conserve space. If you have a portable air conditioner you might be wondering whether you could tilt it or lay it on its side. This will help you divide space better. This article specifically covers can you lay a portable air AC on its side? And if not, Why not?
A portable AC should not be tilted, inclined, or laid on its side or back as this could lead to compressor failure due to oil deprivation. Moreover, doing this will also cause condensate to spill on the floor. However, if laid for storage, always give adequate upstanding time, usually 24 hours for most units.
Portable air conditioners are designed to be operated in upstanding position only. If operated in any position other than that such as on its side, back or at an angle, this could damage its internal fixtures. Especially compressor mounting as the compressor is the major moving component. It is subjected to maximum vibration and most liable to mechanical fatigue.

5 Reasons Why Not To Lay Portable AC On Its Side or Back?
Portable air conditioner can be moved from one room to another conveniently unlike most of the other air conditioners that have to be fixed at a spot.
The mobility is limited to some extent due to necessity of venting via vent hose. However it is still pretty flexible compared to central and window air conditioning units that have to fixed at certain locations. You cannot move them even in the upstanding position.
So it is more likely that a person thinks of the possibility to lay portable air conditioner on its side. The major reasons why you cannot do that is the possible damage to compressor and the inability to gather humidity from air and eventually eliminating it.
1. Damage to Compressor Due To Oil Deprivation
Compressor is the most important component of any air conditioner operating on vapor compression cycle. It is in fact the only necessary moving component in the air conditioning cycle. Compressor pressurizes refrigerant that is later on expanded to get the cooling effect that cools your home.
A Little About Your AC’s Compressor and Refrigerant
Most common types of compressors used in air conditioners are rotary, scroll and reciprocating compressor. Reciprocating compressor were common in the old days.
They were mostly used with R-22 refrigerant. R-22 is ozone depleting substance hence it not used anymore. In fact as of January 1, 2020, production and import of R-22 refrigerant was made illegal in US. For this reason almost all portable air conditioners use either scroll or rotary compressors.
Why Oil Is Necessary for Your Portable AC Compressor
For any air conditioning system, oil is a vital component for its correct and consistent operation. For reciprocating compressor, oil is mandatory for lubrication, removal of heat and for sealing purpose.
In rotary compressor, lubrication is required for contact in between cylinder and rotor. When a scroll compressor starts, the oil sump, bearings, and shaft interact with each other and form an oil supply system.
Effect of Laying Portable AC On AC Compressor
When you lay your portable AC on its side or tilt it at an angle compressor is deprived of the mandatory lubrication oil at certain zones. This causes components of the compressor to collide with each other causing wear and tear.
Result is serious damage to your compressor and eventually destroying your compressor permanently and rendering it useless.
Even if the air conditioner is not operating, putting the unit on one side may affect compressor mounting. The compressor is the most expensive component of the air conditioner to replace or repair. So, if you have to replace your compressor it would cost a good part of the actual price of the complete unit.
In case you know compressor has to be replaced, decide before making the decision whether it is cost effective when your current portable AC value is taken into account. Usually, it is better to buy a new unit.
2. Inability To Retain Condensate in Portable AC
Primary role of compressor is to deliver cool air in the living space making internal environment comfortable. It rejects heat outside by delivering hot air outdoors through vent hose.
Your portable AC also removes humidity from the air as a secondary process called condensation.
Here’s How Your Portable AC Collects Humidity?
When the humid air comes in contact with cool evaporator coils, temperature drops below saturation temperature causing the vapors in air to convert into liquid state. This is called condensation. Water droplets converted from gaseous state are called condensate. Condensate drops into what is call the condensate pan by the action of gravity.
Effect of Laying Portable AC On Condensation
If your portable AC is not in an upstanding position, the condensate water will follow the path of gravity. Thereby when unit is tilted or laying on the side, water will spill on the floor instead of collecting in the condensate pan.
Note: ‘Partially Evaporative‘ and ‘Fully Evaporative‘ are common types of portable air conditioners in market.
They both have what is called self-evaporation technology i.e., moisture is automatically removed through the exhaust hose. Laying portable AC on its side or back will also undermine this aspect of your portable AC.

3. Reduction in Cooling Effectiveness of AC Refrigerant
The refrigerant inside your portable AC has to go through different physical states to bring about cooling.
Let me explain what I mean…
Actually, at different points in AC lines, your refrigerant may be a gas, a liquid, or a mixture of both.
For example, when refrigerant goes to the compressor it is in a gaseous state. It has to be otherwise there will be wet compression that may damage the compressor.
In the same way, when refrigerant moves through the condenser coils, it is converted from gas to liquid. While in the evaporator coils from liquid to gas.
These phase changes depend on heat absorbed or released by the refrigerant. This is crucial to the cooling process in a vapor compression cycle that your portable AC operates on.
When you lay portable AC on the side, oil moves in the AC lines and coils, and mixes with the refrigerant. This Interaction of oil with refrigerant inhibits its interconversion between gas and liquid.
Resultantly, performance of your portable AC will drastically reduce and there will be a possibility of damage to it.
4. Clogging of Filter Drier
A filter drier in a refrigeration system is responsible for removing moisture, contaminants, and even small amounts of lubricant oil from the refrigerant.
Lubrication oil is crucial for compressor internal components to operate smoothly. Some of it however gets added to the refrigerant and finds its way to the cooling oil.
Filter drier removes this compressor oil and allows the refrigerant to freely go through different phases to bring about cooling.
However, it is designed to contain only small quantities of oil at a time, if they travel with the refrigerant.
When you incline or lay your portable AC on its side or back, a large amount of oil travels to the cooling coils, and eventually to the filter drier, causing it to clog.
The result is a reduction in the performance and cooling effectiveness of your AC as well as its inability to remove contaminants and moisture.
5. Damage to Portable AC Inside Components
When you lay portable AC or place it inclined, mechanical apparatus inside it will be affected i.e., mountings, fittings, and internal fixtures.
This damage could especially occur when you impulsively shift your portable AC from an upstanding position. Like sudden placement on the floor on its side or back.
An even more common and detrimental scenario is the transportation of portable AC unit. Whether your vehicle or a delivery van, sudden jerks, and impulsive movements may damage the internal system and setup.
The most I am worried about are those super thin AC coils. They are very delicate and an impact of any kind on them would leak refrigerant.
If this happens, the only option would be to change these coils and refill them with refrigerant.
Can You Lay Portable AC On Its Side for Storage?
After winter set in you may winterize your portable air conditioner taking it away from living space although it is not a necessary thing to do so.
When winterizing portable AC, it is recommended to do so in the upright position.
The critical reason is that after retrieving portable AC from storage some zones of the compressor will be deprived of oil if it was laying on the side. Operating it right away would cause damage to the compressor the due to a lack of lubrication.
Anyways, if you have your portable air conditioner stored on its side, back or any position that is not upright major damage will not be caused until you turn it on. So just keep it in the default upright position without turning it on for sufficient time.
This will cause oil to recover and redistribute in the compressor. Then you may turn it on.
The time for which you should leave it upright depends on the unit you have. The safest choice though, if you have kept it in the wrong position for more than a day, is to keep it unplugged and in this position for about 24 hours.
How to Winterize Portable AC?
If you are storing your portable AC for a long time like till spring, do it right. This will maintain your portable AC, keep it working for a long time and increase its life.
- Detach the power cord, wrap it and store it in the storage compartment on the back of portable AC.
- Uninstall window kit and unscrew the vent hose. Some units have special space to store them. Otherwise store it in a secure suitable place.
- Drain the water in the condensate pan entirely by removing the drain knob to prevent corrosion.
- Extract the filters before storage, clean them and put them back in the unit.
- Store your portable AC in a place away from direct sunlight or below freezing temperatures. Closet, cupboard, basement etc. are preferable.
Can You Lay Portable AC On Its Side for Transportation?

When you have to move your portable AC and you use a mode of transportation like a truck, best is to keep it in vertical default position. Other than that it could have compressor oil deprivation and starting it in this state could damage the compressor.
But another problem could be damage to compressor mounting. It is different to place your unit stationary on its side in storage vs laying it on side while it is moving.