Outdoor Portable Air Conditioner Smart Energy Use

Energy use ratings: EER and SEER

Energy ratings describe how well an electric appliance uses electricity. A higher rating means better efficiency and lower energy bills.

EER (Energy Efficiency Rating)

EER is a simple energy rating that gives you a general idea of a portable air conditioner’s efficiency. Because there are so many variables with outdoor use, EER ratings may be closer to the actual efficiency you can expect with outdoor use. SEER ratings are more common, but they can mislead you.

Use EER only as a guide.

EER is simple to calculate. Divide the number of BTUs by the number of watts a unit uses. In fact, you can even figure it out for yourself if it’s not included in the description of your portable air conditioner.

Typical EER ratings for portable air conditioners range between 8 and 12. HIgher numbers are better.


Units with higher efficiency ratings may have a higher upfront cost. But they can offer long-term savings in electricity costs. Also, more efficient units are often more durable and last longer. This can reduce maintenance costs and extend the lifespan of the unit.

SEER (Seasonal Energy Efficiency Rating)

SEER energy ratings are for central and mini-split air conditioners that cool stable interiors. The tests are done in a laboratory under a specific set of controlled seasonal conditions.

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.

Since you won’t be using yours portable AC in a laboratory, your unit’s actual energy efficiency will be a lot different than the SEER rating. But you can use the rating as a basis for comparing shopping.

Operating Limits: How Your Portable Air Conditioner Handles Extreme Outdoor Conditions

Operating limits refers to how hot, how cold, or how humid the conditions are where you use your portable air conditioner.

Temperature Extremes

If it gets too cold, the motor may freeze. Not usually a problem when using an air conditioner in the summer! But high heat could be a problem. If your air conditioner will be outside in 110ºF (43ºC) heat, you’ll want it to stand up to that heat so you won’t have to.

Put your portable AC in shade to keep it from overheating.

Check the Specs

Before you make any decisions about buying or renting a portable air conditioner, check its technical specifications. This will tell you the minimum and maximum temperatures in which the unit works best and stays safe. Most work best between 115°F (45°C) and 65°F (18°C). Some work best in a narrower range.

High Ambient Heroes

Units that work in harshest environments are called “high ambient” models. They can brave harsh desert environments and can handle temperatures up to 150°F / 65.6°C.

Humidity Extremes

High humidity can also cause problems. Most portable units start to struggle above 60% humidity. Many high humidity climates like [example and example] have humidity levels well below 60% during the hottest part of the day. So when you need the AC the most, it can still be safe and effective to use.

But some areas like stay hot and humid throughout the day. Outdoor fans and shade work better in areas like these.

Electricity Use

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

Smaller units run on typical household currents. But larger units that draw more power may need special outlets and wiring.

Some public areas and rented venues may have restrictions on electricity use which could impact your choice of outdoor cooling method. If you want to use your AC in these places, contact them before purchasing or renting your portable air conditioner just to be sure your unit can meet any restrictions they might have.

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!

Making Your Portable Air Conditioner Safe and Easy to Use

If you’re looking for a powerful portable air conditioner (20,000+ BTUs), be aware that some may come with special plugs that won’t fit certain outlets. To avoid compatibility issues, always check the technical specifications of the unit before purchasing.

Installation Tips: If you plan to use your portable air conditioner for a long time or permanently, you might want to have a qualified electrician adjust the outlet for you. Also, if you’ll be moving your AC unit around, make sure to check what types of outlets are available in the places you’ll be using it. See our page with other installation tips.

Safety Features: Using any electrical appliance outdoors raises safety concerns.

  • All portable air conditioner plugs come with a grounding “earth” pin, which helps prevent electrical shorts and fires.
  • Some units have a GFCI plug, which detects power fluctuations and immediately shuts off the appliance to prevent electrocution. These plugs also have “Test” and “Reset” buttons that are easy to use and should be checked regularly.
  • Some newer models may have an LCDI plug. It detects any leaking current that might occur if the cord gets damaged. This feature is crucial to prevent fires, especially with outdoor use.

Choosing the Right Model: Look for models that use common plug/outlet configurations for your area and are compatible with the electricity supply. Make sure to read the technical specifications of the unit(s) you’re considering.

Watts: A Measure of Energy Use

The energy use of any electrical appliance is measured in watts per hour. At its peak, it may withdraw large amounts of electricity (amps). The amount of amps tells you what kind of electrical outlet the unit needs.

But how a unit uses those amps — how much it converts to watts — shows how much power the unit really has and uses. Large units may list their electricity use by kilowatts which is simply 1,000 watts. The number of watts used also help you estimate operating costs.

Review the technical specification of the unit(s) you are considering. Read our page on basic electricity for more information.

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 are commonly used for outdoor fans. But they serve a different purpose for portable air conditioners compared to outdoor fans. While outdoor fans rely solely on moving air for cooling, portable air conditioners have a more complex cooling process.

A portable air conditioner divides the airflow into two areas: the evaporator and the condenser. Proper airflow across these coils effectively reduces temperatures. As a rule of thumb, aim for a CFM of around 400 (CMS of around 0.1888) per 12,000 BTU/ton of cooling capacity.

Learn more about BTUs and selecting the right size portable AC for your needs. Combine this information to make smart use of your outdoor portable air conditioner and maximize its energy efficiency.

Other Outdoor Cooling Methods

If you have a more open outdoor area that needs cooling, consider outdoor fans, misting systems, or misting fans which combine misting systems and outdoor fans into a single unit.

Swamp coolers (desert coolers) use a similar technology as misting systems (evaporation cooling), but in a contained unit. They are sometimes called air conditioners, but use a different technology than true air conditioners.

Outdoor shades are a nearly universal solution that combine well with every other cooling option.

Take a look at our comparison page to learn which outdoor cooling solutions may be best for you.