Can I Sleep In My Car With The Ac Running?

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Who wouldn’t want the maximum comfort that sleeping inside an air-conditioned vehicle brings? After all, the car is not only a means of moving from one point to another. It can also be a couch where you relax and sleep.

Let’s take a step back. The summer is always a hot time and sleeping in your car may not be a good option.

The experience in winter offers something different; it can be quite tempting. After all, with the A.C on full blast, you can breathe easier and savor the tantalizing excitement of paradise.

However, the hotter or cooler the experience may seem, the more harm it causes to your body in the final analysis.

Can I Sleep In My Car With The AC Running?

No, you cannot and shouldn’t sleep in your car with the AC running. You should not, not even for 20 minutes. It’s simply dangerous.

So, you’re tempted to ask, ‘what’s out of this world if I take a little nap inside my car with the A.C. blazing?

Honestly, nothing is absurd about relaxing inside the car. But there’s a big deal when you expose yourself to the carbon monoxide that the fuel-burning car engine emits.

Do you know what I mean?

Ok, let me explain the science and danger. If you have to put on the AC, the car engine has to run.

As the engine runs, it starts a combustion process in which it burns fuel. The fuel-burning car engine gives off carbon monoxide, a dangerous and poisoning chemical.

The engine also produces a host of other harmful gases. How does the chemical seep into the car cabin?

The poisoning finds its way into your cabin through a wide range of means, including leaks, windows, openings, cracks, and vents.

The more the carbon monoxide stays in the cabin, the more poisoning your body will be exposed to.

Some of the health risks of carbon monoxide include chest pain, fainting, fatigue, shortness of breath, and hallucination.

You can experience dizziness, headache, nausea, or other flu-like symptoms. The case is even more fatal for people who are intoxicated.

They can meet silent death without anyone’s knowledge.

Now, you understand why I’ll always that you shouldn’t sleep inside your car with the AC? But then, I think there’s more to learn about this dangerous poisoning.

Carbon Monoxide Poisoning In Car Air Conditioner

Characteristically, carbon monoxide (CO) is a colorless, highly inflammable, odorless, and tasteless gas.

What it means is that when the harmful gas seeps into your cabin, you won’t be able to tell that it’s already found its way in.

With the help of a carbon mono detector, you can detect. Even at that, you can’t tell the quantity of the gas that’s present in the car.

The AC vent helps diffuse the carbon across the nook and cranny of the car. It’s more dangerous if your car is enclosed in a little space where there’s neither opening nor ventilation to dispense the accumulating poisoning gas.

Carbon monoxide will replace the oxygen that’s present in your blood cells and this leads gradually to slow asphyxiation and death.

Is It Safe To Sleep In A Running Car With The Air Conditioner On?

No, it’s not safe to sleep in a running car with the air conditioners on. To say it pointedly, it is suicidal to sleep inside a car with ac running.

You can get asphyxiated after inhaling the poisonous gas. Remember, carbon monoxide reacts with hemoglobin.

Hemoglobin contains a lot of iron that bonds with carbon monoxide and causes suffocation when inhaled in excess. This is a reason you’re highly likely to die when a large amount of the gas builds up in the car and gags your breath.

This highly flammable chemical often will be sucked into the vehicle cabin through the AC vent. This will cause you to choke in your deep sleep in the car.

What Are Other Risks Of Sleeping In A Running Car With AC On?

Apart from carbon monoxide-related death, you also stand the risk of other problems if you sleep in your car. They include:

Engine Overheating

Due to protracted working, your engine can start to overheat over time. Some of its components may damage if you leave the AC running for an extended period.

Low Battery Power

If the car engine and AC run for a long time, the battery stands the risk of losing a lot of power. A loss in power means the battery may start to drain, malfunction, and ultimately die.

Potential Damage To Radiator

When your car engine overheats, the radiator is one of the victims of the consequences. The radiator can easily damage. This is an extra cost for you.

And how much does a radiator cost? You may want to rethink each time you want to run your car engine with the AC on full blast.


What about a sleep-related accident? An incoming car could swerve and hit you while you’re sleeping inside the car.


Sleeping in a car with the running can also cause you to oversleep. As a result, you may miss out on an important appointment.

You may have intended to sleep for just 5 minutes, but the AC has a way of overcooling. In the end, a 5-minute sleep turns to 3 hours or more.

Is It Legal To Sleep Inside The Car?

I’m sure everyone should be more afraid of death than being caught by the law. Nevertheless, some cities and states in the US prohibit drivers and car owners from sleeping inside their cars.

The reasons vary from city to city. First, the idea is to reduce the rate of mortality resulting from suffocation due to inhalation of excess carbon monoxide.

Again, laws against sleeping inside the car target individual and public safety.

Hoodlums can lynch the sleeping car owner and cart away their property. Homeless people can also use the opportunity to loiter around and constitute a nuisance on the street.

Even in cities where sleeping in the car is not illegal, you still have to obey some rules. You cannot park n restricted areas or on private property.

Not obeying rest stops and signage when parking your car for a nap may attract fines.

For instance, in Hawaii, it’s illegal to sleep in the car between 6 pm and 6 am. In places where there are local parking restrictions, you cannot sleep in your car in Walmart.

If you sleep in your car in Palo Alto, you will be liable to six months in jail or pay a fine of $1,000.

In all, you must learn the laws of your state or city of residence.

What Safety Tips If You Must Sleep In Your Car?

Well, a lot of people use the car as a couch to relax during a stopgap, stopover, or a break at work. If you must sleep inside the car, check if the city allows it. If not, don’t.

However, if your city of residence permits it, then here are things you can do while you relax in the car. This way, you can save yourself and other commuters.

  • Put on a short sleeve if you must sleep in the car. Don’t wear a sweatshirt or a jacket.
  • Set the AC temperature at not more or less than 24 degrees Celsius.
  • Before sleeping, park your car in an open and well-ventilated space for free airflow.
  • Ensure your car exhaust system and intake valves are in good condition.
  • Turn off the AC and other climate controls.
  • Put up a warning sign to alert other commuters that someone is inside the car.
  • Create a few openings around the windows to disallow the seeping carbon monoxide from building up.
  • Fill the gas tank to full capacity.
  • If you must run the AC, make sure you are always with the CO detector. This way you can know whether the gas is seeping into the car cabin.
  • Switch off the engine and remove the key from the ignition.
  • Make sure you have your cell phone with you to call 911 or inform someone about your location.
  • If you’re sleeping inside an electric car, you’ll have no worry about CO because the car doesn’t emit gas.

Final Thoughts

The next time someone asks you, ‘can I sleep in my car with the AC running,’ you won’t take a yes for an answer.

I understand how comfy it can be to recline in the passenger seat for a 5-hour non-stop sleep. But it’s much more than that; it’s a matter of life and death. It’s about personal and public safety.

It’s about not violating the laws of many cities and states that prohibit sleeping in the car. It’s about deterring some homeless people from idling around the streets.

As the engine burns fuel, it gives off a hazardous and poisoning gas that’s can harm sensitive parts of your body.

Why not stay inside your room or rent an apartment in a hotel or motel to sleep over the night?

Sleeping in an Air conditioner car is not worth the risk associated with it. Stay and drive safe.