Small Room Portable Air Conditioner Buying Guide

How to select and buy the best small room portable air conditioner. Is it better to buy a portable home air conditioner based on BTUs, energy efficiency or a size?

Either you are looking to buy a big or small room portable air conditioner, one is common; they operate the same. Surrounding warm air is drawn inside the AC where it is cooled to the set temperature.

Room portable air conditioners have two great advantages; they are versatile and mobile. Portable ACs are designed to cool one room while they dehumidify the area at the same time. Some units have a separate mode for dehumidifying the air, plus fan and the heat pump. The best portable AC is the multi-functional unit that can be used year round.

A Buying Guide

BTU should match the room size. What's the cooling power?

Selecting the portable AC with more power is not always better.

Choosing the right portable air conditioner is important for your comfort. The most important criteria is how many BTU's one AC has. BTU's is short from British Thermal Units, and it describes cooling power and capacity. If you choose a small room portable air conditioner with less BTU than your room needs you will have a problem not cooling the room to the desired temperature. If you choose more BTUs than needed, your AC is stronger, but it will cycle off too quickly without achieving desired results.

When talking about BTUs, the most common sizes of room portable air conditioners are from 5,000 to 30,000 BTUs. The cooling unit with the approximately 5,000 BTUs is good enough for the room size of up to 150 sq. ft, while the most popular 14,000 BTUs size air conditioner is sufficient for the room size from 350 to 450 sq. ft. However, this is a rough estimate which can be different from a situation to a situation; such as how many people are inside the room, number of heating sources (stoves...) is the room exposed to the sun, or it is in  a shade...

What's the AC efficiency?

Choose your small room portable air conditioner with the proper and higher value of EER or Energy Efficient Ratio. Higher EER factor means that your AC is more efficient while it costs less to operate. It is calculated BTU/Watts and most often you will see AC with the EER ranging from 8 to 11. Energy Star air conditioners are high efficient units, which allow you to apply for the tax rebates, but they generally cost more.

Noise level

Decibel rating and the noise level is something you don't want to skip, when choosing the best portable air conditioner. As these small room units are installed in a room where you or your family members are present, lower noise level means an increased comfort level while the louder machine is annoying.


As the room portable air conditioner cools the surrounding air it has to discharge the generated heat somewhere. This is why the proper venting is important. Most of the time you will receive a window kit when you buy an AC. Sometimes you have to buy a different type of a vent kit, for your particular window type. Keep in mind that even a small room portable air conditioner has to vent the exhaust out.

Some portable air conditioners are equipped with a single hose while other with two. AC with one hose draws the surrounding air in for cooling and exhaust the warm air out through the hose.

Two-hose portable AC uses one hose to expel the warm air out and the other to draw the fresh air from outside in. These ACs are designed with a higher cooling BTU in order to provide more cooling power.

Drain system

Since every air conditioner dehumidifies the surrounding air it is convenient to have an auto-drain system to drain collected water outside rather than into the tray. Such a portable air conditioner that drips all the condensation will need to be emptied more often.

Easy to move

Portable AC means small, compact and mobile. Portable design includes casters or wheels and handles for easy transport from one room to another.

Benefits of buying a small room portable air conditioner

  • Room portable AC is mobile; it can be used for cooling residential apartments, rooms, commercial offices, computer server rooms... anywhere where window type cannot be installed or the central system cooling is too expensive, and move from one room to another.
  • Portable AC is versatile; it cools, heats, dehumidifies and purifies the air.
  • Portable and small air conditioners are easy installation. They don't have to be permanently installed as they are standing directly on the floor and using window vent type.
  • Economical solution as they are used to cool only one room, vs. central air conditioning systems.


Small room portable air conditioner is a good solution for spot cooling, where window type AC and central air conditioning are too expensive or not a viable option. If you want a simple guide how to select the right portable AC, calculate BTUs (see here) by figuring out the room size in square feet of the room it needs cooling and the amount of heat that room receives.

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