Can Hot Air from an Outdoor A/C Unit Cause a Fire in Grass?

There are a few ways in which air conditioners can start a fire. According to the National Fire Protection Association, approximately 2,800 house fires annually are caused by ill-functioning air conditioners. However, the hot air from the outside unit of an AC is not likely to cause a fire in the grass.

The Hot Air from an AC Unit

It is normal for the outdoor unit of an AC to release hot air. This is the excess heat that has been stripped from the indoor air. But even though it is hot, this air will not cause a fire. The temperature is just around 160°F, which is still far below the flashpoint. Hence, it is safe to place your outdoor unit near grass and plants.

The Real Cause of Fire

A properly functioning AC unit will not pose a fire threat. It is some sort of error in the system that may start a fire, such as:

Short Circuit

Electrical errors are the most common reason for a house fire caused by an air conditioner. Fluctuating electrical flow or a power surge can trigger a short circuit, which may start a fire.

If you are still using a fuse box, it might be time to consider switching to a circuit breaker panel. These are a lot safer because the switch will turn off instead of burning when a short circuit strikes. Use one switch for your AC unit to keep it separated from other appliances in your home.

Electrical Wire Issues

Besides the short circuit, electrical wire issues could also cause a fire. It is advisable to regularly monitor all the exposed wires in your house, especially the ones connected to your AC unit. Make sure they are still in their safe states. It is also important to keep it away from water and flammable materials.


An overheating AC unit may also trigger a fire. AC units tend to overheat if:

  • The air filter or coils are dirty
  • They are worn and torn
  • They are oversized
  • They are improperly installed
  • They contain incorrect parts.

Regular maintenance can prevent the risk of your AC overheating. As long as you take care of your appliance well, your AC is unlikely to overheat and ignite a fire.

Flammable Materials Nearby

Always remember to keep your AC unit a safe distance from any flammable things in your house. Although it wouldn’t directly cause a fire, the presence of flammable materials near the unit will instantly make the situation worse when a fire occurs. Experts recommend putting your AC at least three feet away from flammable goods.

Air conditioners are not easily flammable if they are in good shape. As long as you keep doing your regular maintenance, your appliance should be safe. Treating every problem immediately will also help prevent bigger issues. This not only will keep your house safe but also increase the appliance’s performance and efficiency, as well as possibly prolong its lifespan.

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