Portable Air Conditioner Buyer's Guide

Warm weather and high humidity levels can make your indoors stuffy, hot, and unpleasant. Air conditioning is a great way to cool off. Unfortunately, many central air conditioning systems are inefficient, over-taxed, or out of date. Therefore, they are unable to cool our homes and offices properly. Many times, people turn to a traditional window air conditioner for cooling, but these units are not always an option since some homeowners' associations and apartment complexes do not allow them.

Furthermore, there are many rooms and spaces that cannot support a window-mounted unit and thus, remain warmer than desired because of a lack of proper ventilation or poor air circulation. Examples of these spaces include garages, sun rooms, and workshops. This is precisely where portable air conditioners, or PACs come in. These small, portable cooling systems are effective solutions that can be used to supplement an existing central cooling system in one room or to cool a single room in a standalone configuration. As an added benefit, these units dehumidify the air while cooling it. That means your indoor environment stays both cool and comfortably dry.

There are many portable AC models available. Each unit has a specific BTU (British Thermal Unit) rating, which loosely indicates its cooling capability. However, choosing the right portable air conditioner for your application involves more than just picking the one with the highest BTU level. There are many more elements to consider. The following information will help you develop a better understanding of portable ACs, so that you can make an educated investment in the unit that best suits your needs.

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

About Portable Air Conditioners
Size and Efficiency
BTUs of Window Units vs. Portable Units
Setup and Exhaust Hoses
Exhaust Hose Lengths
Single Hose vs. Double Hose
Cooling Multiple Rooms
Eliminating Collected Water
Electrical Outlet Requirements
IT Specialists
Noise Level
Maintenance
Special Features

About Portable Air Conditioners

A portable air conditioner is a self-contained appliance that typically sits inside the space that needs to be cooled. Here, it provides traditionally air-conditioned air. Unlike window ACs, portable air conditioners are not designed to be installed in a window.

Portable ACs differ by brand, maximum cooling area, venting configuration, and special features—like remote controls, oscillation modes, and fan speeds. As part of their design, most PACs dehumidify as they cool, and some units feature a specialized dehumidify-only mode. This allows the unit to function as a standalone dehumidifier as well as a portable air conditioner. Some PACs may also double as heaters and even air purifiers.

Size and Efficiency

Perhaps the most important thing to determine when choosing a portable air conditioner is the size you need. An air conditioner that is too small will not be able to keep up with your cooling demands. The following list is a loose estimate of the level of heat coverage to expect based on a PAC's BTU rating. These are only rough estimations because many factors play a role in the heat capacity and efficiency of a portable air conditioner. Other factors include ceiling height (cubic space); insulation type (building construction); climate (ambient temperature); and the average heat load in the space, which can include heat produced by other people, electronics, or outside drafts that may travel inside through doors and windows.

Calculating BTUs
To estimate how many cubic feet a portable air conditioner can efficiently cover based on its BTU measurement, use these general guidelines. All of these specifications assume that you have a standard 8-foot ceiling.
- 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

Please remember that these calculations are simply estimates based upon a well-insulated bedroom located in an average climate.

In addition, note that if your space has lots of windows or heat-generating appliances; if you reside in a warm, humid state like Florida; or if you are cooling a poorly insulated room, such as a garage or workshop, you will need to increase the size and power of the PAC you purchase. The importance of using a sufficiently sized and appropriately powered unit for your space cannot be stressed enough. If you underestimate these requirements, you could end up with a portable air conditioner that falls short of your expectations in cooling performance.

If you need help determining the right size PAC for your needs, call our product experts at (800) 934-9194 for a free consultation and an expert recommendation.

BTUs of Window Units vs. Portable Units

When compared to a traditional window air conditioner, a portable air conditioner with the same BTU rating is actually slightly less powerful. This difference can be attributed to several factors. For example, sometimes manufacturers may inflate a portable unit's BTU rating. Or a portable AC may vent hot air into the room you are trying to cool, instead of to another location using a vent hose. (Window units automatically vent hot air to the outside.) In light of this comparison, we recommend that you buy a slightly more powerful PAC than you think you might need.

Setup and Exhaust Hoses

All portable air conditioners exhaust hot air as part of the cooling process. This hot air is typically siphoned out of the area being cooled using a hot air discharge, or exhaust, hose. The exhaust hose can be vented out of a window, into a drop ceiling, or through a wall to an adjacent space. Depending on the PAC model you choose, window kits and drop ceiling panel kits may be available or included.

Setup requirements for exhausting air vary based upon the model. Most PACs come with a standard window kit, which is typically made of hard, durable plastic. However, these window kits are not always one-size-fits-all, and individual adjustments may have to be made. If you have non-standard size windows, you will want to make sure that the portable air conditioner you choose can be configured to properly exhaust hot air out of your windows.

The most common issues you may encounter when setting up a portable air conditioner's exhaust hose are the following:

Window Screens — When installing a PAC window kit, many people ask the question: "Do I have to remove my screen from the window?" The answer depends on your particular window style and screen. Most of our customers find that they can leave the screen intact because the exhaust hose does not extend out from the window.

Casement/Crank Windows — There are no portable air conditioner units that come with a window kit that will work for a casement, or crank, window. However, some customers have fashioned a solution using Plexiglas to cover their entire window area and then cutting a small hole into the Plexiglas for the hot air discharge hose.

Sliding Glass Windows/Doors — Setting up your exhaust hose to work with a sliding glass window or door is possible with almost all units. However, depending on the specific PAC model, the window kit may not fit the full length of the door. If this is the case, it will be necessary to build a solution that ensures that the rest of the gap not covered by the window kit is properly insulated.

Exhaust Hose Lengths

The exhaust hoses that expel the hot air from portable air conditioners come in a standard length (usually 5 ft.). In general, lengthening the exhaust hose of a unit is not recommended. Lengthening your exhaust hose may void your manufacturer warranty and may potentially cause your air conditioner to overheat. If you require an exhaust hose longer than 5 ft., you will need to consider a commercial-grade unit, such as a Movincool portable air conditioner.

Single Hose vs. Double Hose

There is a bit of a debate about whether a single exhaust hose or double exhaust hose system is more efficient when using a portable AC. Although the research is inconclusive, it is helpful to understand how single- and double-hose PACs differ.

One-Hose PAC — A single-hose portable air conditioner works by drawing in air from the space, cooling it, and returning most of the air back into the room. A small amount of this air will be used to cool the unit and will be blown out of the air conditioner's exhaust hose. This can cause your room to harbor slightly negative pressure. If you adjust for this pressure by drawing uncooled air into the room from adjacent spaces, such as from underneath the door or from gaps around windows, then your unit's cooling efficiency will be slightly affected.
Dual-Hose Unit — A dual-hose PAC works by taking in air from the outside through one of its hoses and using that air to cool the unit. Then, the hot exhaust air is expelled through a second exhaust hose. As such, a dual-hose unit does not create negative pressure inside the room being cooled, and it may be more efficient than a single-hose PAC. However, dual-hose units use warmer, unconditioned air to cool their compressors, which can result in slightly weakened efficiency. Also, depending on the design, a dual-hose PAC may use two internal fans, which results in slightly higher energy usage.
Hot Temperature Consideration — Another important point to consider when deciding between a single-hose and a dual-hose portable AC is the outside temperature. If you have a dual-hose setup, where the intake hose is pulling air in from outside when the temperature is high (say approaching 100°F), then the air being drawn in to cool the unit down may actually be hotter than the unit's compressor. Under this scenario, the unit may not function properly or it will be less efficient than if it was in a scenario where the intake-air was being drawn from inside the room, where it's cooler.

The Bottom Line: The verdict is out. There are pros and cons to dual-hose units, and there has not been a definitive study to confirm their benefits over single-hose units. If you are uncertain about which unit to purchase, remember that some dual-hose units can be modified very easily to become single-hose units. All you have to do is detach the second hose using the instructions in your PAC's owner's manual.

Cooling Multiple Rooms

Many people are interested in cooling multiple rooms with a portable air conditioner. Whether or not this will work for your particular environment depends on several factors:

Temperature of the Room: A portable air conditioner can only lower the temperature in your room roughly 10-15 degrees.
Climate You Live In: Humidity level and temperature have a direct impact on the effectiveness of a portable air conditioner.
Size: An accurate estimate of the space you want to cool, including ceiling height.

Like a window-mounted air conditioner, a portable air conditioner works best at cooling its immediate area. If your space has very large openings from one room to another, then it is possible that adjacent spaces may see a small cooling effect. However, the cold air will not travel down a hallway or through narrow doorways. You may want to use fans to help circulate the air.

Eliminating Collected Water

When a PAC cools the air, it also removes water from the air, acting like a dehumidifier. There are many different ways that a portable air conditioner deals with this condensate water.

Buckets: The simplest units have an internal container that needs to be drained regularly—as often as every 8 hours to once a month, depending on your conditions. Most units have a drain plug that needs to be removed to drain the unit.
Self-Evaporating: More sophisticated PACs can evaporate a great deal of moisture into their hot air exhaust. Therefore, there is little or even no water to empty.
Fully Evaporative: A few portable air conditioner models are completely evaporative, like the DeLonghi Pinguino PAC W130E. This means that you never have to dump the collected water. Evaporative units are especially desirable when you want the freedom to leave it running unattended.
Gravity Drain: All portable air conditioners support the option of a permanent water drain hose connection. This allows collected water to continuously drain out to a nearby floor drain using the force of gravity.
Condensate Pumps: Condensate pumps are also available to help pump the collected water through a drain hose. These pumps can move water in an upward direction to drain water up and out through a window, for example.

Electrical Outlet Requirements

Most portable ACs use a typical household 110/120-volt power outlet and require no special wiring. Of course, as air conditioners can draw a significant amount of energy, you must be cautious not to overload a circuit with multiple high energy-consumption devices (for example, placing a refrigerator or a dehumidifier on the same circuit). PACs that cool with 14,000 BTUs and above as well as commercial-grade units may or may not require special outlets and wiring. Some models may need a dedicated 20-amp outlet or 220-volt wiring. Read the product description and specifications to determine the power requirements when selecting a unit. The energy consumption will vary, depending on the model and your environmental conditions.

IT Specialists

Many of the portable air conditioners we sell go into computer server rooms. These units are often used as supplemental cooling units or as primary cooling units in server rooms on the weekends when the central air conditioning is generally shut off.

Choosing the right portable air conditioner for a server room is sometimes a challenge because most server rooms do not have easy window access or may be in interior rooms. This makes venting a complication. As a solution to this, customers usually direct the hot air exhaust hose into a drop ceiling space or through a hole in the wall to an adjacent room. Please call us at (800) 934-9194 to discuss whether this is an option for your application.

The DeLonghi PAC W130E comes with a complete kit that allows 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 in this manner, but they must be elevated toward the ceiling to allow their exhaust hoses to reach the full ceiling height.

Noise Level

Noise, sound, background noise, white noise—whatever you call it, it does exist. You simply cannot find a silent portable air conditioner. These units cannot be totally silent because they use motorized fans and compressor systems that cool and circulate the air. Even though PACs are not silent, the amount of sound they produce varies considerably. Ask yourself the following questions when deciding what type of unit will best suit your indoor needs:

Will the unit be in my bedroom? This is the number one area where people find sound the most intrusive. If you are a person who does not like any noise while falling asleep, having a portable air conditioner with a timer that can be set to come on after you are deeply asleep may be the ideal solution. On the contrary, many people enjoy the white noise created by a portable air conditioner. They find it soothing and helpful when drifting off to sleep.

The Bottom Line: Understand that a sound will come from any style PAC you choose, and it's just a matter of finding the level of sound that you are comfortable with. Buying a unit with special features that will help you minimize the sound, such as a timer and multiple speeds, is beneficial.

What can I compare the sound level to? Some units list the decibel rating of the system at each fan speed. You can compare these ratings to other indoor appliances, such as the sound you hear from a normal box fan or the hum of a refrigerator. This gives you a good point of reference.

The Bottom Line: Remember that sound is different to each individual, and even decibel results can sometimes be misleading. Many things can affect a PAC's sound level, such as the position of the unit, if you have carpeting, what type of furniture you have, the furniture's distance from the unit while it is running, and the fan speed.

Maintenance

Maintaining your portable air conditioner is simple and requires very little effort. Most units work as a "set it and forget it" appliance. However, to get the most out of your investment, you must keep up on general maintenance. This includes:

Cleaning air filters as needed (usually once every summer).
Making sure that installation is correct for maximum efficiency.
Defrosting the unit completely if ice builds up on the coils. Do not use the unit until it is completely defrosted.
Consulting a professional if you hear a rattling sound or think that the compressor isn't working properly. Check your warranty for more specific information on the parts and services covered.
Draining your unit before storing it away.

Properly maintaining your unit will ensure that it has a long life span. Portable ACs can last anywhere from 6 to 15 years, depending on the model.

Special Features

Many portable air conditioners on the market offer special features that enhance your cooling (and/or dehumidification, heating, and air purification) experience. These features add convenience to your life and allow you to optimize your portable AC to best fit your needs. Some of the special features to consider when shopping are:

Casters for easy mobility
Digital controls
Remote control
Multiple fan speeds
Carrying handle
Dehumidify-only mode
Heating capability
Air filtering
Integrated timer

There are also a number of accessories you can purchase to customize your portable AC to further meet your needs.

Still Have Questions?

For more information on specific products and ways to improve your indoor environment, review our extensive product listings and other educational materials. Not sure what's best for you? We can take the guesswork out of decision-making. Contact our product experts toll free at 1 (800) 934-9194. We want to help you make your indoor environment a healthy one.