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Article Image: "Portable Air Conditioners Frequently Asked Questions (FAQ)"

Portable Air Conditioners Frequently Asked Questions (FAQ)

Portable air conditioners are great cooling solutions that can act as a primary source of cooling for a room or add a supplemental boost of cool air to assist an existing HVAC system. These portable appliances are great for use in bedrooms, dens, computer rooms, garages, and many other applications.

For easy accessibility to the topics in this article, use the list below:


What is a portable air conditioner?

A portable air conditioner (PAC) is a self-contained portable appliance that cools the air in a single room or moderately sized space. Unlike traditional window ACs, portable air conditioners do not sit in the window. They typically sit on the floor within the space you are trying to cool.

What is required to set up a portable AC?

Requirements vary based on the model. All portable ACs exhaust hot air as part of the cooling process. This hot air is usually directed out of the cooled space using a hot air discharge hose, also known as an exhaust hose. This air hose is often vented out of a window, into a drop ceiling, or through a wall to an adjacent space. Depending on the model you choose, window venting kits and drop ceiling panel venting kits may be available or included with your purchase.

For more information about venting your portable air conditioner, read our Knowledge Center article How to Vent Your Portable AC.

Whynter ARC-13S

Will I need to empty water? Will water collect in the portable air conditioner?

When air is cooled, moisture is removed from the air. Therefore, all portable air conditioners remove water from the air while they are cooling. There are many different ways that various PACs deal with this condensate water.

The simplest portable air conditioners, like the Danby Premiere DPAC12010H, have buckets that need to be emptied periodically, from as often as every 8 hours to just once a month. More sophisticated room air conditioners, such as our DeLonghi portable air conditioners, automatically evaporate moisture along with hot air exhaust. Hence, there is no water to empty.

All portable air conditioners are equipped to drain water continuously through a gravity drain hose. Many models, including the Sunpentown WA-1410 Portable Air Conditioner and Air Purifier, are also designed to use condensate pump accessories, which help pump the drained water through a hose and move it in an upward direction to drain out of a window, for example, or across long distances to an alternate location.

What size air conditioner (BTU level) do I need?

In contrast to traditional window air conditioners, portable air conditioners are slightly less powerful at the same BTU level. This occurs for various reasons, from manufacturers inflating their listed BTU ratings to an air conditioner giving off heat that is not properly exhausted away from the cooled room. We recommend you buy slightly more AC than you think you might need to ensure you have enough cooling power. Use the following guidelines to determine the portable air conditioner capacity that your space requires. These calculations assume that you have standard 8-foot ceilings:

  • 7,500 BTUs will cover 150 sq. ft. x 8-ft. ceiling = 1,200 cubic feet
  • 9,000 BTUs will cover 200 sq. ft. x 8-ft. ceiling = 1,600 cubic feet
  • 10,000 BTUs will cover 300 sq. ft. x 8-ft. ceiling = 2,400 cubic feet
  • 12,000 BTUs will cover 400 sq. ft. x 8-ft. ceiling = 3,200 cubic feet
  • 13,000 BTUs will cover 450 sq. ft. x 8-ft. ceiling = 3,600 cubic feet
  • 14,000 BTUs will cover 500 sq. ft. x 8-ft. ceiling = 4,000 cubic feet

We typically classify our portable ACs according to the following room square footage guidelines:

  • Less than 300 Square Feet: These portable ACs are great for small rooms and other compact areas like bedrooms, nurseries, or home offices.
  • Less than 500 Square Feet: Portable air conditioners in this category are best suited for cooling medium to large areas such as living rooms and larger offices.
  • Greater than 500 Square Feet: These portable air conditioners work well in commercial and industrial applications, including large computer server rooms, manufacturing facilities, and special event spaces.

Keep in mind that you may need less BTU power if you live in a cooler region or only plan to use your PAC in the cooler evening hours. On the contrary, if you live in a warmer region or plan to use the unit during peak temperature hours you might require more BTU power. This is also true if you will be running multiple heat-generating appliances in the same room. You should also adjust your BTU requirement against the number of people who usually inhabit the room.

Typically, each person will generate about 2,000 BTUs of heat. Lastly, consider the number of windows in your room as well as the location of the room. Does sunlight regularly shine through your windows to make the room feel naturally warm? All of these things can affect the cooling performance of your portable AC. For more in-depth information about choosing a the right cooling capacity, read our Portable Air Conditioner Buyer's Guide and our article 5 Things to Consider When Buying a Portable Air Conditioner.

If you need help weighing the many factors that affect portable AC performance and ultimately making a decision about the right BTU power for your room, please call us at 1-800-934-9194 for a detailed consultation.

Can I lengthen the exhaust hose?

In general, you should not lengthen the exhaust hose of a portable AC. Depending on the manufacturer, this may void your warranty and potentially cause your air conditioner to overheat.

Can I discharge the hot air out of a sliding glass door or sliding glass window?

Danby DPAC12099 Vertical Installation

Most portable air conditioners can be easily vented through traditional double-hung windows, also known as vertical sash windows, using window kit accessories. These same accessories can typically be used for venting a portable air conditioner through a sliding glass window as well. For example, the Danby DPAC10011 User Manual provides detailed instructions for installing this portable AC into a sliding glass window. The configuration should look similar to diagram on the left.

Carefully check the manufacturer’s specifications to ensure that your portable AC can be installed in sliding glass windows or if additional accessories should be purchased for installation.

Venting portable air conditioners through sliding glass doors is much more complex than simple window installations. The window installation kits used for traditional windows typically don’t extend far enough to cover the height of the door. For sliding glass door installations, we recommend using at least two window installation kits that are designed to work with your particular portable AC to completely cover the door opening. The two window installation kits can then be secured together using screws. Plywood and Styrofoam can also be used as covering and insulation material when installing a portable air conditioner into your door frame.

Regardless of the installation that you intend to perform, always consult the owner’s manual for instructions, guidelines, and cautionary information.

What should I use to cool a server room?

Portable air conditioners are often used for supplemental cooling in computer server rooms or as the primary cooling source in these rooms on weekends, when central air conditioning may be shut off. We recommend DeLonghi portable ACs for these cooling jobs because DeLonghi portable ACs use fully self-evaporative technology. This means that you will never have to manually remove collected condensation and can leave the portable AC running unattended.

Most server rooms do not have easy window access and may be interior rooms, which makes venting a complication. As a solution, you can direct the hot air discharge hose into a drop ceiling space or through a hole in the wall to an adjacent room. Our Movincool CM12 is a great choice for server rooms because it is a ceiling-mounted portable air conditioner. It can be easily mounted above a standard drop-ceiling, as shown below.

Movincool CM12 Installation Diagram

Other commercial portable ACs are also available with complete kits that allow you to easily discharge hot air into a drop ceiling while allowing the unit to remain at floor level. Less expensive residential units may also be used, but they must be elevated toward the ceiling to allow their hot air discharge hoses to reach full ceiling height.

I have a casement/crank-out window. Can I configure my PAC to exhaust air out of this type of window?

Unfortunately, there are no portable air conditioner units with a window kit that will fit a casement window. Some customers have creatively fashioned a solution using Plexiglas to cover their entire window area. Then, they cut a small hole into the Plexiglas for the hot air exhaust hose.

What electrical requirements do portable ACs have? What about energy consumption?

Most PACs use typical household 115/120 Volt power and require no special wiring or outlets. Of course, as air conditioners can draw a significant amount of energy, you must use caution not to overload a circuit with multiple high-energy-consumption devices. Some of the higher BTU PACs (14,000 BTU or higher) or the commercial-grade portable air conditioners may or may not require special outlets and wiring. Please read product descriptions for more information. Energy consumption will vary depending on the model and your environmental conditions.

Will a portable air conditioner work for multiple rooms?

It depends. Similar to a window-mounted air conditioner, a portable air conditioner is effective in cooling its immediate area. However, the cold air will not travel down the hallway or through narrow doorways. If a space has very large openings from one room to another, then it is possible that adjacent spaces may experience a slight cooling effect. Fans can also be used to help circulate the air for additional cooling coverage.

What is the difference between a single-hose design and a dual-hose design?


Some portable air conditioners have one hot air exhaust hose, and some have two air hoses: one for air intake and one for hot air exhaust. A single-hose portable air conditioner will take air from the room that it is in, cool it, and return most of that air back into the room. During this process, a small amount of that air will be used to cool the unit and will be subsequently blown out of the air conditioner's exhaust hose. This creates slightly negative pressure within the room being cooled, as a small amount of air is constantly being removed from the room. If this negative pressure is anticipated by drawing unconditioned air into the room from adjacent spaces, then the cooling efficiency is slightly affected.

A dual-hose portable air conditioner, such as the Friedrich P12B, works by taking in air from the outside through one hose and using that air to cool the unit. The hot exhaust air is then expelled through the second hose. This process does not create negative pressure inside the room being cooled. However, there is a tradeoff. Dual-hose units use warmer, unconditioned air to cool their compressors, which results in slightly less efficiency. They also employ two internal fans, which can mean slightly higher energy usage. At this time, we have not seen conclusive evidence that either solution, single- vs. dual-hose, is better than the other when all factors are considered.

Do I have to remove the screen from the window when using my window kit?

The answer to this question varies based on your particular style of window and screen. However, most of our customers find that they can leave the screen in the window because the exhaust hose of their portable AC does not extend out from the window.

Still Have Questions?

For more information on a specific portable air conditioner or any of our other products that can improve your indoor air, review our extensive product listings and visit our Knowledge Center. Not sure what’s best for you? We can take the guesswork out of decision-making. Contact one of our air treatment specialists toll-free at1-800-934-9194. We want to help make your indoor environment healthy and comfortable.

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