Does a wall or window room air conditioner need a dedicated circuit?

Thursday, May 14, 2020

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. 


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