Can You Sleep in a Car With the Windows Up?

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As a camper, you may have the dilemma of not having a place to stay.

You may also find it too exhausting to find your way back home or to your Airbnb after a day of hiking and scavenger hunts. 

Therefore, if you find yourself in that position, it would be great to know whether or not you can sleep in a car with the windows up. 

Can You Sleep in a Car With the Windows Up?

It is entirely safe to sleep in a car with the windows up. Contrary to widespread assumption, your vehicle is not airtight. Replacement of oxygen occurs every few hours. While it is not an ideal place to get a good night’s sleep, you won’t have to worry about running out of air.

This article will explore several important things when sleeping in a car

How well you can sleep in a car with the windows up, the safety concerns window-up camping might have, and any downsides to sleeping in a car with the windows up.

Our Cars Are Not Airtight

First, it is essential to note that vehicles are not airtight. There are several ways for vehicle air to escape or enter your car while sleeping in it.

The primary way for vehicle air to get in will be through the vents. Air can flow freely through these holes because doors do not cover them. 

The car will use the same airflow to bring in outside air.

However, the amount of air brought in this way is usually not enough for most people to feel it. 

Air coming through vents is also already cooled down and dehumidified because it has run across the evaporator coils in your AC unit.

If you have your car’s AC on, the air coming through the vents will still be comfortable.

Carbon Monoxide Poisoning

The creation of carbon monoxide occurs when something burns, such as gasoline or natural gas.

According to a 1998 study, carbon monoxide in motor vehicle exhaust emissions accounts for most carbon monoxide poisoning deaths in the United States.

Carbon monoxide cannot escape through open windows when sleeping in a vehicle with the windows up because the closed windows will block it. 

Carbon monoxide would have to be coming out of the vehicle’s exhaust to get inside a car and reach dangerous levels.

If running a vehicle with its engine on and windows closed, carbon monoxide can quickly build up to dangerous levels.

The exhaust of a running machine can contain carbon monoxide that is deadly if inhaled.

It is important to note that some people are more sensitive to carbon monoxide than others. 

Other chemicals in the exhaust can also be dangerous even if there is no carbon monoxide present. 

Precautions to Avoid Carbon Monoxide Poisoning

Can You Sleep in a Car With the Windows Up 1 Can You Sleep in a Car With the Windows Up?

Carbon monoxide is an issue for anyone sleeping in a car, but there are several precautions we can take:

  1. Don’t smoke inside the vehicle and run the engine while sleeping.
  2. Have sufficient ventilation when using an auxiliary heater.
  3. Have a carbon monoxide detector in the car. Get out of the vehicle immediately and seek fresh air if it goes off.

Security Concerns

One concern with sleeping in a vehicle is security.

If you leave your car unlocked, someone may break into it and steal belongings inside.

Also, if your windows are down while you sleep, more noise will wake you up when something happens to your car.

If you are worried about security, park in a 24-hour parking lot. 

These places have full-time patrol, and it is easier to find your car if you know the area. 

This way, you will be able to see anyone approaching your vehicle more easily. 

It is still possible that someone could come to your car, but you will likely spot them before they spot you. 

It might be safer to plan on sleeping in a car with the windows up. 

If you are sleeping in an unfamiliar area, it will be easier to get around if your windows are up. 

If you decide to sleep with your windows down, lock your doors and park between other cars to make it more difficult for someone to break into your vehicle without waking you up.

Sleeping In Your Car Can Be Safe

Sleeping in your car with the windows up does not need to be unsafe. If you follow these tips, you can effectively reduce any safety concerns.

First, get a good night’s sleep before trying to get one in your car. 

This way, you will be well-rested and won’t make any stupid mistakes when trying to rest in your vehicle. 

Secondly, keep the car keys in the same spot every day.

Keeping them in a familiar place makes it easier to find them in the dark when we need them. 

Keeping your keys somewhere on your body can be effective if you are worried about seeing them in the dark or losing them. 

Otherwise, you might have to replace them.

I would try this before putting the keys under the floor mat unless you have a good feeling that no one will find them.

A wallet in your back pocket can also work for this purpose, although it might be uncomfortable to lean against the window with all that metal.

Lastly, carry an essential kit with you when sleeping: 

  • A flashlight 
  • Pocket knife
  • Extra batteries 
  • Fix-a-Flat 

You can use these items defensively and help you find your keys and get back into your car at night. 

People carry these kits for camping even when sleeping indoors, so it makes sense to do so when sleeping outside.

Suitable Weather Conditions for Car Camping

Different weather conditions offer various challenges when attempting to sleep in your car. 

I would only recommend sleeping in your car with the windows up during cold weather or warm weather if you have an effective way to keep yourself and your belongings warm and safe during the night.

The Hot Seasons

You can undoubtedly sleep with the windows up during hot weather, but it might be more comfortable to open the windows instead. 

When opening your car’s windows, ensure that you are not choosing an area where exhaust gases could seep into your vehicle.

Be aware of any possible rain as well. If it is raining, do not open your windows or have a wet sleeping area. 

If your car gets wet inside through an open window, be sure to wipe everything down before trying to sleep in the car. 

What About the Cold Seasons?

If you can afford a quality sleeping bag and don’t mind its price, I would highly recommend getting one. 

Materials that block all light make the best sleeping bags.

You can zip yourself up in a suitable sleeping bag and truly feel like you are in a bed.

It is easy to adjust the temperature of your sleeping bag, and there will be no concern about having enough ventilation.


Sleeping in your car with the windows up is not ideal. 

There are better places to have your good night’s sleep. However, you can still do it safely and comfortably. 

To have a safe experience, follow the mentioned tips closely, and you won’t have any problems sleeping in your car.

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