How Long For Portable AC To Cool A Room?

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Updated May 15, 2023

If you’re shopping for the best air conditioner, you may wonder how fast portable AC units work. The time it takes for a portable AC to cool a room varies, but it usually takes 30 minutes to several hours. To maximize cooling, choose the right size AC, keep doors and windows shut, and maintain the unit regularly.


  • A portable AC unit cools a room similar to the standard window air conditioner.
  • A dual-hose portable air conditioner will offer faster and more efficient cooling thanks to the enhanced airflow.
  • Your portable AC system should cool your space in about 20 minutes as long as your BTU rating is appropriate for your area.

After all, if you’re experiencing a heat wave, you need enough BTUs of power to quell high outdoor temperatures. Luckily, portable units are an intelligent cooling solution with multiple operating modes and limited energy usage compared to central air systems. So, if you want to know how long does it take to cool a room with a portable AC, read on.

If you want an energy-efficient home, consider learning how long you can run your portable air conditioning system. To keep cooling times to a minimum, you should know how many BTUs you need before buying a quality portable air conditioner. While mobile units aren’t the most powerful models, they’re a reliable option if your central air conditioning system has failed in one room.

How Fast Can a Portable AC Unit Cool a Room?

Unlike heavy window units, portable AC systems typically feature easy-rolling casters that make it easy to move from room to room. In addition, the outdoor climate and square footage rating will heavily affect how quickly a portable air conditioner unit will work. Read our comparison of a portable AC vs window AC to learn more about these differences.

Insider Tip

Choose a portable air conditioning unit with air filters and a dehumidifying mode for the best indoor air quality.

How Do Portable Air Conditioning Units Work

Portable air conditioners cool your space by pulling warm air through the motor and dispersing cool air throughout the room. In addition, most models feature a single or dual-hose system to help move excess hot air or moisture outside.

Are BTUs Important for a Portable Air Conditioner?

BTUs (British Thermal Units) are used to measure thermal energy. For AC units, you need 20 BTUs for each square foot of space you want to cool. If you do not pick the correct rating, your AC unit will have insufficient cooling power for your floor space.

Tips for Cooling Your Living Space with a Portable Air Conditioner

You can help your portable AC system cool your space with a few simple steps. If you have a dual-hose model, ensure that the window kit doesn’t have any openings for cool air to leak from your space.


Ensure that your portable AC exhaust hose fits snugly in the window vent kit you’re using. If not, you will get reduced cooling power due to air leaks.

Place the Portable Air Conditioner in the Shade

Use curtains to block direct sunlight or place your portable AC unit in a typically shaded window. This will lighten the load on your portable AC system and make it more efficient.

Minimize Your Heat-Emitting Appliances

Your AC unit will not work as quickly if you’re cooking with an oven or running unnecessary computers, TVs, or lamps in a small space. If you want cool air in a hurry, shut down any heat-emitting appliance that isn’t in use.

Ensure that the Exhaust Hose is Straight

If there are any bends or kinks in your dual-hose portable air conditioner, hot air cannot efficiently vent outdoors. Your unit should cool more efficiently after you straighten the heat drain hose.

STAT: According to US Census Bureau data, 92% of Americans making $100,000 or more have some form of air conditioning. (source)


How long do portable air conditioners last?

Experts suggest that most portable AC units should last between five and ten years. The lack of in-home ductwork makes maintenance simple for most portable air conditioner problems. Lastly, regularly clean the washable filter and empty the water tank if your unit features dehumidifying mode.

Is running a portable AC unit 24/7 a good idea?

It isn’t energy efficient to run your AC nonstop, putting additional wear and tear on your unit. Experts recommend utilizing the programmable timer to schedule air conditioning cycles for your home. In addition, try fan mode if you’re in a humid climate.

Why is my portable AC blowing warm air?

If you’re experiencing a lack of power from your portable AC unit, you’re likely low on Freon. Without Freon or refrigerant, the coils inside the unit will not cool down the air, resulting in warm air coming from your AC unit.

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