All 120-volt wall or window air conditioners that are around 8,000 BTU or more will have a sticker on the side, like the one shown above, that require a “single outlet” (dedicated) circuit. The reason is that the National Electrical Code (NEC) requires that any cord-and-plug connected appliance that is fastened in place be limited to 50% of the rating of a multiple outlet circuit to which it is connected. NEC 210.23(A)(2) states that: “The total rating of utilization equipment fastened in place, other than luminaries, shall not exceed 50-percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastend in place, or both, are also supplied." 

    So a wall/window air conditioner with a rating of over 7.5 amps would require its own circuit on a 15-amp breaker, or over 10-amps on a 20-amp breaker. If the applliance is not “fastened in place,” such as a portable dehumidifier, then it is allowed to be up to 80% of circuit rating, per NEC 210.23(A)(1).

        Also, see our blog posts What are the most common problems with wall/window air conditioners? and Can I run a window air conditioner on a portable generator?

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  To learn more about heating and air conditioning systems, see these other blog posts:

• How can I find out the SEER of my air conditioner? 

• My air conditioner won't turn on. What's wrong? 

• How can I find out the size of my air conditioner? 

• How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump? 

• Where is the air filter for my central air conditioner and furnace? I can’t find it? 

• Does an old air conditioner use more electricity as it ages? 

• How did homes stay cool in Florida before air conditioning? 

• What is wrong with an air conditioner when the air flow out of the vents is low?

• Why has the thermostat screen gone blank? 

• Why does it take so long to cool a house when an air conditioner has been off for a while? 

• Why is my air conditioner not cooling enough? 

• What are the most common problems with wall/window air conditioners?  

• Will closing doors reduce my heating and cooling costs? 

   Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.