Portable Air Conditioners:
Power Use, Safety and Installation

Knowing a few basics about any portable air conditioners your thinking about buying or renting can prevent headaches and disappointments in the future.

Power Use

Look for models that use the most common plug / outlet configurations for your area and are compatible with the electricity supplied to your area. Read our page on basic electricity for more information on plug types and electrical supply. Review the technical specification of the unit(s) you are considering.

Be careful not to overload the outlet powering your unit -- don't plug other appliances into the same outlet if they'll need a lot of power, too.

Smaller units are designed to run on typical household currents. Larger units that draw more power may need special outlets and wiring.

It's no fun to pull out your portable air conditioner to use for the first time on a hot day,
only to learn you can't even plug it in!

Keep in mind some areas may have restrictions on electricity use which can affect your choice of outdoor cooling method. It's a good idea to contact these places before purchasing your portable air conditioner just to be sure your unit can meet any restrictions they might have.

Plugs and Outlets
Larger, more powerful units (20,000+ BTUs) may have special plugs that aren't compatible with certain outlets. Check the unit's technical specifications. If your portable air conditioner will be set up long term or permanently, consider having a knowledgeable electrician rewire an outlet for you. If you will be using it in several locations it's wise to check into what kinds of outlets are available where you will be using it. If you need more cooling than a standard outlet will supply, consider using multiple smaller units, or providing your own portable power with a generator.

All plugs on portable air conditioners have a grounding (earth) pin that helps prevent electrical shorts and fires. Newer models may have a LCDI (Leak-Current Detection and Interruption) plug. These detect any leaking current, which would happen if the cord was damaged or frayed, which could cause a fire.

For personal safety some units are fitted with a GFCI (Ground Fault Circuit Interrupter) that detects power fluctuations that might cause electrocution and shuts off the appliance immediately. Both LCDI and GFCI plugs have "Test and "Reset" buttons that are simple to check whenever you set up your portable air conditioner.

Watts
The power of any electrical appliance is measured in watts per hour. It may withdraw large amounts of electricity (amps), and the amount of amps tells you what kind of electrical outlet the unit needs. But how those amps are used -- how much is converted to watts -- shows how much power the unit really has. Large units may list their electricity use by "kilowatts which is simply 1,000 watts. The number of watts used will also help you estimate operating costs.

CFM (Cubic Feet per Minute) / CMS (Cubic Meters per Second)
The amount of air a portable air conditioner can move is measured in cubic feet per minute (CFM) or cubic meters per second (CMS). These ratings for portable air conditioners serve a different purpose than they do for outdoor fans. An outdoor fan's cooling ability is based entirely on moving air, so those numbers are high compared to an air conditioner.

A portable air conditioner's airflow is sometimes broken down into two areas: the evaporator and the condenser. A certain amount of airflow is needed inside the unit across the evaporator and condenser coils to achieve temperature reductions. In general, look for CFM of around 400 per "ton / 12,000BTU, or look for CMS of around .1888 per "ton / 12,000BTU.

SEER (Seasonal Energy Efficiency Ratio or Rating)
SEER ratings are established by the U.S. Department of Energy to describe how well air conditioners work. A higher SEER rating means better efficiency and lower energy bills. The difference between a SEER 9 and a SEER 13, for example, can mean an energy savings of about 30%. Ratings typically range between 6 and 25.

SEER is calculated by dividing the number of BTUs by the number of Watts it uses. The tests on these units are done in a laboratory under a specific set of seasonal conditions. Since you won't be using yours in a laboratory, your unit's actual energy efficiency will be quite a bit different than the rating. But use the rating as a basis for comparing shopping.

EER (Energy Efficiency Ratio or Rating)
EER is similar SEER. It rates the electrical efficiency of an air conditioner, but does not take into account the seasonal factors. Since the seasonal factors of the SEER are almost impossible to duplicate outside of a laboratory, EER ratings may be much closer to the actual efficiency you can expect.

EER calculations are similar to SEER: the number of BTUs provided by an air conditioner is divided by the number of Watts it uses. Period. In fact, you can even figure it out for yourself if it's not included in the description of your portable air conditioner. Typical ratings for portable air conditioners range between 8 and 12.

Units with higher efficiency ratings may be more expensive initially, but cost savings in electricity use can offset that expense. And more efficient units typically last longer.

Noise
Portable air conditioners can be noisy. Surprisingly, some of the larger ones make less noise than the smaller ones. If you'll be using yours at night when you're trying to sleep, or near other people such as at festivals or trade shows, you'll want to be especially aware of noise levels. In fact, some areas may have noise restrictions. Check with local authorities before you purchase or rent your portable air conditioner to be sure your unit will be in compliance.

Bottom threshold of human hearing	10dB
Recording studio	20dB
Quiet living room	30dB
Quiet office or library, refrigerator	40dB
Quiet conversation	50dB
Average office noise, clothes dryer	60dB
Average conversation, dishwasher	70dB
Average factory	80dB
Typical home stereo volume	90dB
Heavy truck	100dB

Most portable air conditioners list decibel ratings which will give you an idea of how noisy they will be. The decibel rating (dB) is a common measurement of sound. These typically range from 50dB (about as loud as a quiet conversation) up to 70dB (about as loud as a dishwasher).

• The actual noise level a portable air conditioner will make can vary from what the actual rating is. The actual level can be affected by:
• how the unit is installed -- installation on a solid base of packed earth or concrete will be quieter than on a raised metal base that allows the unit to vibrate
• what the area is like around it -- setting it up where there be plants or walls around it can muffle its noise
• and how close people are to it when it's operating -- Putting the main unit outside of your tent or structure may make it quieter for you inside, but it also may make it noisier for those around you outside.

Keep in mind noise ratings usually refer to the general long-running noise of the fans in the unit. Lower fan speeds run more quietly than higher fan speeds. There is often an additional noise when the compressor turns on to boost the cold air. This noise can be quite noticeable, especially in a normally quiet environment.

If at all possible try to see and hear the unit in operation before your purchase. If you're renting, make sure your rental consultant is aware if you need an especially quiet unit.

Operating Limits
Operating limits refers to how hot, how cold, or how humid the environment is in which a portable air conditioner will be used. If it gets too cold, the motor may freeze. Not usually a problem when using an air conditioner in the summer! But high heat and humidity could be concerns. If your air conditioner will be outside in 110 / 43 degree heat, you'll want it to be able to stand up to that heat so you won't have to. Same with the humidity.

Check the technical specification of the portable air conditioner your are thinking about buying or renting. This will tell you the minimum and maximum temperatures within which the unit will work safely and efficiently. Many will work best in temperatures over 115°F / 45°C or under 65°F / 18°C; most will work best in a narrower range. Also look for humidity level operating limits. Most portable air conditioners will not work properly above 60% RH (relative humidity).

Units that will work is harsher environments are called "high ambient" models. These are used in harsh desert environments and can handle temperatures up to 150°F / 65.6°C

Safety

Safety refers as much to the design of a portable air conditioner as it does to how it's set up.

Safety Ratings
Where you can use any particular portable ac will depend on what kind of safety rating it has. Independent agencies such as Underwriters Laboratories (UL) test electrical appliances and determine in which types of areas they are safe to operate. You can find out more about these agencies at safetylink.com.

• UL ratings for electrical appliances designate safe use for one of 3 kinds of locations:
• DRY -- for indoor use and dry locations ONLY. Don't use a DRY rated appliance in damp or wet locations. Most portable air conditioners are for dry locations only. These need to be positioned inside the area you are cooling, on dry ground. Their motors, components and connections don't have the special safety designs to handle the dust and moisture of open outdoor environments.


• DAMP -- safe for protected outdoor use, for example, open walls with a solid ceiling and dry floor; not good for direct contact with water such as rain or puddles, but outdoor humidity is fine. These models can be temporarily placed outside a structure with the cool air hoses leading inside. Be sure it has protection around it, over it and under it to keep water off of it, especially if it will be installed permanently. Allow at least 18 / 45 cm of clear space around it for adequate air flow. Never use a DAMP rated portable air conditioner in wet locations.


• WET -- safe for unprotected outdoor use, ok to get rained on; rarely applied to portable air conditioners. Most often seen on the largest units and some high ambient units.

Installation

You have to be extra careful when setting up and using any electrical appliances outdoors. There are simply more hazards outdoors than indoors. Following are some precautions to consider before choosing an installation site for your portable air conditioner. Please review these points carefully since improper installation could reduce the cooling capacity, damage the unit or even cause personal injury.

• Do not use in areas where it will be exposed to rain or water unless it is specifically rated for safe use in wet environments
• Do not use in areas where the temperature or humidity are outside the allowable operating range.
• Do not install a portable ac in sloping areas. The unit may move or topple over even if the casters are locked.
• Install a portable air conditioner only in areas that can withstand the weight of the unit. Smaller units may weigh well under 100 lbs (45 kg), but the big units of 5-tons and more can weigh over 500 lbs (227 kg).
• Allow 18 inches / 45 cm of unobstructed airflow for both the air inlets and outlets.
• Do not use in areas where leakage of flammable gas may occur, or in an atmosphere of excessively corrosive gas or vapor.
• Make sure any connections that are outdoors are waterproof. Seal with electrical or Teflon tape if necessary.

For more information on using portable air conditioners outdoors safely, go to our page on electrical safety outdoors.

Read the next page to learn about the costs involved in owning or renting a portable ac.

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