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What Gauge Extension Cord for Air Conditioner? – Answered

Written by Edwin Jones / Fact checked by Andrew Wright

what gauge extension cord for air conditioner

Extension cords are available to quickly connect the AC unit when the outlet is too far. But choosing what gauge extension cord for air conditioner can be a bit of a challenge.

Generally, the AC unit may be plugged into a 14 gauge, 12 gauge, or 10 gauge extension cable temporarily, depending on the AC unit’s current and how long the cable is.

Current Requirements of Air Conditioners


Different air conditioners have different current needs. Generally, air conditioners with higher cooling capacities (or BTUs) will need more current.

For instance, a 5000 BTU window air conditioner uses up to 6 amps; a 10,000 BTU unit uses around 11 amps; and an 18,000 BTU model needs as much as 20 amps.

Also, air conditioners differ regarding their starting currents. The starting current is the amps needed to get the AC motor started, and typically, this current is higher than the normal operating power of the appliance.

The starting current for window AC rated at 5,000 BTU can reach as high as 9 amps. Meanwhile, a 10,000 BTU unit may need as much as 16 amps to begin its operation.

Why are these facts important? Well, the electrical demands of ACs affect their wire sizes, which you will see below.

Wire Gauge for Extension Cords


The right extension cord for an air conditioner unit should consider the starting and running currents of the AC and the distance of the AC from the outlet.

A thicker cord (which happens to be a lower gauge number) can carry more current. The length is also significant as shorter cords reduce voltage drops. Picking cables with these characteristics ensures that an air conditioner can draw enough current during its operations.

A 14 gauge extension cord may be enough for window air conditioners rated between 5,000 and 8,000 BTUs. On the whole, thicker extension cords are needed for AC units with higher ratings.

The table below shows a summary of extension cord thicknesses for portable air conditioner, window air conditioners, and mini-split units.

Cooling capacities (BTU) Running current (amps) approximate Starting current (amps) approximate Minimum wire gauge
5,000 6 9 14
6,000 7 11 14
8,000 9 13 14
10,000 11 16 12
12,000 13 18 12
15,000 16 22 10

Take note that 15,000 BTU is the highest rating available for a window air conditioner at 110v/120v. Thus, air conditioners with a higher cooling capacity will need a 220v extension cord or a high voltage extension cord.

Also, take note that extension cord gauges listed above consider that the length is around 50 feet. 14 gauge is good for a 15 amp air conditioner up to 50 feet, but it’s best to use the shortest possible extension cord for your needs. Don’t use long cables needlessly.

50 feet is most likely enough, especially considering that the average bedroom is only around 14 x 16 feet.

Frequently Asked Questions

Can I use a heavy duty extension cord with an air conditioner?

As long as the heavy duty extension cord meets the wire gauge listed above, that extension cord may be used.

Can I use a 15 amp extension cord for air conditioner?

A 15 amp extension cord may be used for smaller air conditioners as long as it meets the AC unit’s current needs. Also, make sure the cord actually supports the amperage you need it for.

For instance, a 16 gauge cable can only handle 13 amps; in this scenario, it won’t reach the 15 amps mark.


What gauge extension cord for air conditioner? 14 gauge is good for up to 8000 BTUs; 12 gauge is good for up to 12000 BTUs; and 10 gauge is good for up to 15000 BTUs.

Always remember, though, that extension cords may be used only as temporary connections for an air conditioner. ACs should always have permanent outlets and dedicated circuits.

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