Portable Air Conditioner Buying Guide

Since many central air conditioning systems are out-of-date and inefficient, they can’t properly cool certain areas of our homes. Bedrooms, offices, garages, and server rooms are often warmer than desired because of a lack of proper ventilation or poor air circulation. This is precisely where portable air conditioners come in: They're small, portable cooling systems that can quickly and efficiently cool specific areas in your home or office.

Plus, using a portable AC for spot cooling may help you save on your overall cooling costs. Just be sure to turn up your central thermostat a few degrees and let the portable AC do its work.

This buying guide will help you develop a better understanding of portable ACs, so you can make an educated investment in the model that best suits your needs.

For easy accessibility to the topics in this guide, use our topic list:

About Portable Air Conditioners Size Ventilation and Exhaust Single or Double Exhaust Hose? Efficiency Draining Condensate Electrical Outlet Requirements Noise Level Maintenance Cooling Server and Computer Rooms Heating Options Where Do You Need A Portable AC? Special Features

About Portable Air Conditioners

A portable air conditioner is used to provide supplemental cooling to specific areas in your home or business. They don't require permanent installation, but most require a window for ventilation or a separate space to direct the system's exhaust. Most models dehumidify as they cool, and most are also easily mobile.

Portable ACs differ by brand, maximum cooling area, venting configuration, energy efficiency, and special features—like multiple operating modes, remote control operation, programmable timers, and specialized air filters.

Size

The most important thing to determine when choosing a portable air conditioner is the size. An air conditioner that is too small won’t keep up with the cooling demands of your environment. If it’s too large, the AC will cool the area and shut down before removing excess moisture from the area—leaving unwanted moisture in your air.

The following list is an estimate of the coverage area to expect based on a portable AC’s BTU (British Thermal Unit) rating, which is the unit used to measure cooling power. These are rough estimates because many factors play a role in the cooling capacity of a portable air conditioner, but you’ll get an idea of the best size for you.

To estimate how many cubic feet a portable air conditioner can efficiently cover based on its BTU measurement, use these general guidelines.

• • 7,500 BTUs will cover 150 square feet x 8-foot ceiling = 1,200 cubic feet
  • 9,000 BTUs will cover 200 square feet x 8-foot ceiling = 1,600 cubic feet
  • 10,000 BTUs will cover 300 square feet x 8-foot ceiling = 2,400 cubic feet
  • 12,000 BTUs will cover 400 square feet x 8-foot ceiling = 3,200 cubic feet
  • 13,000 BTUs will cover 450 square feet x 8-foot ceiling = 3,600 cubic feet
  • 14,000 BTUs will cover 500 square feet x 8-foot ceiling = 4,000 cubic feet
  • 24,000 BTUs will cover 740 square feet x 8-foot ceiling = 5,920 cubic feet
  • 60,000 BTUs will cover 1,700 square feet x 8-foot ceiling = 480,000 cubic feet

Ventilation and Exhaust

All portable air conditioners vent hot air as part of the cooling process. This hot air is typically vented out of the area being cooled using an exhaust hose and can be vented out of a window, drop ceiling, sliding glass door, or through a wall. Most portable ACs come with window kits or drop ceiling panel kits that include the needed exhaust hose and parts.

For more detailed information about ventilation, read our article How To Vent Your Portable AC.

Common Considerations:

• Sliding Glass Windows/Doors: Setting up your exhaust hose to work with a sliding glass window is possible with almost all portable ACs. However, depending on the specific model, a window kit may not cover the full length of the sliding glass door. If this is the case, the gap will need to be filled with other material like Plexiglas. We suggest these portable ACs for sliding glass doors and windows.
   
• Window Screens: Many of our customers are concerned about window screens when they consider purchasing a portable AC. Although hot air will be exhausted out the window, most screens are unaffected because the exhaust hose doesn’t extend out from the window.

Single or Double Exhaust Hose?

Portable ACs can be single- or double-hosed for exhausting hot air and pulling air in to cool. Some models have both exhausting options. Here is a breakdown of both options:

• Single-Hose Portable ACs: 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 appliance and will be blown out of the air conditioner's exhaust hose.
   
• Dual-Hose Portable ACs: A dual-hose portable air conditioner works by taking in air from the outside through one of its hoses and using that air to cool the unit. Then, hot exhaust air is expelled through a second exhaust hose. As such, a dual-hose portable AC does not create negative pressure inside the room being cooled, and it may be more efficient than a single-hose portable AC. However, dual-hose units use warmer, unconditioned air to cool their compressors, which can result in slightly weakened efficiency as well. Also, depending on the design, a dual-hose portable air conditioner may use two internal fans, which results in slightly higher energy usage.

If you’re uncertain about which unit to purchase, remember that some dual-hose systems can be modified very easily to become single-hose portable ACs. All you have to do is detach the second hose using the instructions in your owner's manual. Only interested in dual-hose units? Check out these dual-hose portable ACs.

Efficiency

Portable ACs tend to be energy efficient and can save you money on your monthly electric bill. Efficiency is measured by the portable AC’s Energy Efficiency Ratio (EER); generally speaking, the higher the EER, the more efficient the model. A rating of 10 is typically considered a very good rating for portable ACs.

Read our Lower Your Energy Bill with a Portable AC article for more about portable air conditioners and efficiency.

Draining Condensate

When a portable AC cools indoor air, it also acts like a dehumidifier and removes water from the air. Portable ACs have different ways of handling this moisture buildup:

• Fully Self-Evaporative: Some models are completely evaporative, meaning the AC exhausts all condensate and you never have to dump the collected water. These are especially desirable when you want the freedom to leave them running unattended.
   
• Partially Self-Evaporating: Units can evaporate a great deal of moisture into their hot air exhaust, and there is little or no water to empty. How often you’ll have to drain the water will depend on usage and environmental conditions.
   
• Gravity Drain/Drain Hose: 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—and also means you won’t have to drain the water manually.
   
• Condensate Pumps: Condensate pumps are available as separate accessories 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 of an area (through a window, for example).
   
• Buckets: The simplest portable air conditioners have an internal container that holds extra water and needs to be manually drained regularly.

Electrical Outlet Requirements

Most portable ACs use a typical household 120-volt power outlet and require no special wiring. However, some powerful portable ACs, such as commercial-grade units, may require special outlets. Read the product description and specifications to determine the power requirements when selecting a room air conditioner. A standard NEMA 5-15 plug image looks like the plug to the right:

Noise Level

Portable air conditioners make noise, because they use motorized fans and compressor systems that cool and circulate the air. Many people consider it “background noise,” others are concerned with appliance noise. If you’re concerned about noise in your room, we suggest buying a portable AC with special features that minimize the sound. Features to look for include a programmable timer, multiple speeds, and a Sleep mode.

Some portable air conditioners list the decibel rating of the system at each fan speed. You can compare these ratings to other indoor appliances, but remember sound is different to each individual. Many conditions can affect the sound level, such as the position of the unit, if you have carpeting, what type of furniture you have, and the fan speed.

For easy reference, use the comparison chart below to get an idea for the level of sound a portable air conditioner will make based on its decibel measurement.

Installation and Maintenance

Maintaining your portable air conditioner is simple and requires very little effort. Most systems work as a "set it and forget it" appliance. However, to get the most out of your investment, you should keep up on general maintenance to ensure it has a long lifespan. Suggested maintenance includes:

• Clean air filters as needed (usually once every summer).
• Ensure it’s installed correctly for maximum efficiency.
• Defrost the unit completely if ice builds up on the coils.
• Drain your portable air conditioner before storing it.
• Check your warranty for more specific information on the parts and services covered.
• Consult the manufacturer or another professional if problems arise.

Cooling Server and Computer Rooms

Additional cooling is needed in many server rooms, and portable ACs are often used as supplemental or primary cooling systems in these areas. When considering an AC, overestimate the amount of BTUs needed to cool the space; these areas get very hot with electric equipment running. Exhausting your AC is another consideration, because many server rooms don’t provide access to windows. Our customers usually direct the hot air exhaust hose into a drop ceiling or through a hole in the wall in these cases. Check out our suggestions for computer/server room portable ACs.

Heating Options Portable ACs that offer a Heat mode generate heat either through a heat pump or electric heater. Electric heat is suggested for cold, northern climates while heat pumps work best in moderate temperatures. In winter months, a heat pump extracts heat from outside air and disperses it throughout the area. It can reverse its system and cool areas as well. Heat pumps tend to be more efficient than electric heaters because they simply transfer heat. In contrast, units with electric heat convert electrical energy into heat using a heat strip in the unit. While this method uses more electrical power to heat than a heat pump, it also can handle colder environments. Interested in a portable AC with heat? Check out our bestselling portable air conditioner heaters.

Where Do You Need A Portable AC?

Now that you know more about Portable ACs, let’s review your options:

• Small Spaces: Portable air conditioners for rooms up to 300 square feet tend to be cost-effective and efficient. ACs between 7,000 and 10,000 BTUs can quickly cool areas like bedrooms, small offices, or one-car garages.
   
• Medium-Sized Areas: For living rooms, offices, and workshops, look for portable ACs between 10,000 and 16,000 BTUs. Features include multiple modes, timers, and automatic restart.
   
• Large and Commercial Spaces: Cooling manufacturing facilities, large server rooms, and outdoor event spaces can be challenging. Commercial-grade portable air conditioners can handle these large, hot areas.
   
• Garage/Workshop: These areas tend to have poor ventilation and air circulation, so we suggest one of these powerful portable ACs.
   
• Room With Sliding Glass Doors: Some AC models include window kit extension kits that make simple installation in sliding glass doors. Check out our suggested portable ACs for sliding glass doors.

Special Features

Many portable air conditioners offer special features that enhance your cooling experience. These features add convenience and save you money on energy costs. They include:

• Self-evaporating technology
• Directional air control
• Remote control
• Washable air filters
• Casters for easy mobility
• Programmable timer
• Digital controls
• Multiple fan speeds
• Carrying handle
• Additional modes: Dehumidify, Fan, Heat, Automatic, Energy-conserving

Still Have Questions?

For more information on specific portable air conditioners and other indoor air treatment solutions, review our extensive product listings and visit our Learning Center. 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.