The Fire Dangers of Window-Mounted Air Conditioners



Recently, the ABC program Good Morning America did a story describing the fire risks posed by air conditioners. According to a National Fire Protection Association study quoted by the piece, air conditioners are the cause of roughly 2,800 home fires per year.

While the “Air Conditioner Dangers” piece is definitely worth a watch, it’s also worthwhile to spend some time digging into the report as well.

Window Air Conditioner Fire Risks

The NFPA data indicates that window-mounted air conditioners pose an outsized risk.

The NFPA website features a page specifically on the fire risks of air conditioners, with a link to a detailed 2012 study. In the study, the authors point out that, “Room air conditioners appear to have a higher fire risk relative to usage than central air conditioning, but reported fire incident data no longer separate the two.”

They go on to say that while the ratio of households using room air conditioners versus central ACs is 1-to-3 (i.e. 25% of homes use room air conditioners), the ratio of all room AC- versus central AC-related fires is 3-to-5 (i.e. 37.5% of fires are caused by window AC units).

Adjusting for the relative frequency of these two types of ACs—to look at how many fires would be expected in equal numbers of window units and central units—indicates that window-mounted AC units are 1.8 times more likely than central ACs to cause a house fire.

This increased fire risk with window AC units is likely due to poor installation and usage practices.

Elsewhere in the study, it mentions that 38% of AC fires originated with the ignition of an electrical wire, or the insulation covering such wires. Likely culprits, as mentioned in the Good Morning America video, are:

  • Window unit electrical cables
  • Extension cords used to power window units
  • Home electrical wiring overtaxed due to a window unit being plugged into a power strip or plug splitter

It is especially imperative to consider this information now, as July and August account for 20% and 18% of all air conditioning-related fires for the entire year. In other words, we’re just starting the two month period in which nearly 40% of all AC-related house fires start.

How you can minimize the fire risk of your air conditioner.

For starters, if you use a window unit, make sure that the power cable is in good condition, with no nicks, tears, or signs of overheating.

If you can at all help it, do not plug it into an extension cord or power strip—plug it directly into a wall outlet. If you must use an extension cord, use a 12 or 14 gauge cord that is as short as possible, and which is indicated specifically for use with window ACs. Make sure that the draw of your window AC doesn’t exceed the cord’s rating (for example, the product overview of the linked cord indicates that it has a 15 amp, 1,875 watt maximum capacity—it would be unsafe to use with an AC over that rating).

Lastly, make sure that you clean your air conditioner’s filter regularly, and ensure that the intake and exhaust are unobstructed, with at least 3 feet of clearance. If you see any sign of electrical failure or improper operation, cease using your unit until you can have it inspected by an air conditioning expert.

However, the best bet for ensuring your safety is to have a new central air conditioner professionally installed. As the study showed, central ACs do cause fires as well, and much of this is likely due to improper installation. The experts at Gilmore Heating Air & Solar can help you select the AC that’s right for your home, install it so that it will work safely and properly, and give you tips on how to ensure safe, reliable operation in the future.

To learn how Gilmore can keep your home cool and safe, give us a call at 888-868-2316, or use our contact form to schedule an appointment. It’s hot out there, so don’t wait!