There are so many reasons to sleep in a car. A quick doze in a car is a perfect break to a hectic workday. An hour for lunch just translates to an hour nap! Cars aren’t just for quick catnaps though. Car camping is definitely a thing. Maybe you’re out hiking and enjoying nature and you lose all track of time. By the time you reach your car again, you’ll be too tired to get back home or to a hotel. You decide to spend the night in your vehicle.
In some situations, sleeping in a car is the perfect solution. You can recline that seat back and settle in. You’re even shocked that it’s not that uncomfortable. You find it easy to close your eyes and drift off. You didn’t even have to count sheep. Everything is good. Right?
You did leave the windows rolled up though. Did you just make a fatal mistake? Are you risking that you’ll never wake up? Is it safe to sleep in a car with the windows rolled up?
The short answer is yes. Sleeping in a car with the windows rolled up is perfectly safe. Despite popular belief, vehicles are not airtight and the air within a vehicle is replaced on average every 1 to 3 hours with no mechanical ventilation. You wont have to worry about running out of fresh oxygen by sleeping with your windows up.
Cars Are Not Airtight
Most of us have been led to believe that our cars are airtight. However this just isn’t the case.
If you’d like to test this idea out, drive past an area where a skunk recently passed through. Even with the air conditioning turned off and all the windows up, the skunk’s stink will still creep into your vehicle.
Remember, cars have ventilation systems. The vents in the dashboard of your car actually lead to the outside air. A lot of people aren’t aware of the fresh air and recirculation features of their car’s climate control system. Somewhere on every car’s control panel, there are two AC buttons; one features a car symbol with an arrow circling inside and the other has a car with an arrow entering from the outside.
The first button is the recirculation button. It will recycle and cool the air already in your car. The second button is the fresh air button and it pulls air from the outside into the interior of your car. The existence of this fresh air button alone proves that outside oxygen is entering your car all the time.
What do Studies Show?
In fact, there’s more proof than just a fresh air button. Back in 1998, a group of environmental health researchers at Harvard University set out to measure the air exchange rate in stationary cars. This is that study.
Researcher J.H. Park and his colleagues tested air changes per hour (ACH) in stationary vehicles. They observed the effects of different conditions, such as different combinations of open or closed windows and AC on or off. They used three different cars in this experiment.
It was discovered that in a parked car with the windows closed and no mechanical ventilation, the air was completely replaced within 1 to 3 hours. Basically, without the driver doing anything at all (i.e. sleeping), the air in a car will be refreshed every 2 hours on average. In order to decrease the oxygen levels below the safe threshold, there would have to be more than 9 people sleeping in one single car. You presumably aren’t riding around in a clown car with an entire circus, so that shouldn’t be an issue.
Cars Are Not Watertight, Either
While we’re at it, your car isn’t watertight either. There’s a reason we carry tools in our vehicles that will break out car windows in case of submersion. The reason is that cars are water-resistant, but not watertight. After hitting the water, it will begin to spill in through these openings, such as the vents. The pouring in is slow, but it’s steady. It will sink the car.
What about the rubber seals found around car doors? These weather seals are meant to withstand normal weather situations, like rain or snow. However, there is a big difference between heavy rain and total submersion underwater. Likewise, thinking back to the skunk smell example, seals don’t make the car airtight either.
In general, sleeping in a car is completely safe. Is it totally impossible to die in a car with the windows rolled up? No, of course not. Where there’s a will, there’s a way. So far, there are no known credible records of an adult accidentally suffocating in a car with closed windows. You need to make sure you are not the first.
Tips for Sleeping In Your Car
First of all, if you’re sleeping in your car in the summer, heat is your concern, not suffocation. It is tragically common to read a news report about an infant dying from heatstroke after being left in a hot car. Small children are confined to a harnessed car seat. They are unable to open a window or door to release the heat.
An adult, however, can feel when the temperature in a vehicle is too high and then is able to crack a window. If you were asleep in a car that suddenly got dangerously warm, your innate survival instinct would wake you before you could die. After all, haven’t we all had a night in a bed where we woke up too warm and kicked off all the covers? You can always prevent overheating with a solar-powered fan, by the way.
Second, it is important to note that all of this advice does pertain to properly maintained vehicles. A malfunctioning car can spell out danger. People have died inside vehicles with faulty or compromised exhaust pipes. In fact, a common exhaust danger rears its ugly head every winter. Drivers will unknowingly run a car while the tailpipe is blocked by snow. If the dangerous fumes can’t be expelled, the carbon monoxide travels back inside the vehicle. It can kill a human in minutes.
The good news is that cars do have safety measures. If your car was built after 1975, it will be outfitted with a catalytic converter. Thanks to EPA regulations, all cars built after 1975 are required to have one. A catalytic converter helps convert dangerous carbon monoxide exhaust to carbon dioxide. Still, the catalytic converter alone cannot keep you alive. A faulty or blocked tailpipe could still spell disaster.
It’d be wise to prepare and catch a catastrophe before it can wreak havoc. Before ever sleeping in your car, give your car a good once over. You can even take it to a mechanic. Is everything in good working order? You don’t want to miss anything. You especially want to check out the tailpipe. If you have any doubts about its ability to work safely, replace it.
Third, to keep yourself safe while you snooze, place a carbon monoxide detector in your car. We have them installed in our houses, so it just makes good sense to keep one in the car as well. It’s best to purchase a battery-powered model so you aren’t dependent on an outside power source. This detector’s battery lasts for up to a year. Yes, it lasts over 365 days! This simple-to-use device will alert you immediately if it detects high carbon monoxide levels. Keep it close to your ear so it will wake you.
Still Not Feeling Safe Sleeping With the Windows Up?
If you’re still uneasy sleeping in a car with the windows up, there’s always the option to just open the windows. There’s no badge of honor for leaving the car windows closed all night. Plus, those closed windows plus your breath will equal some major condensation on your windows. It’s merely an inconvenience that can be swiped away with a hand, but you can avoid it if you prefer!
It’s safe to sleep in a car with windows down as well. It’s best to not roll them down all the way, just to make sure no human can squeeze through in the middle of the night. In most cases, the worst that can happen is that a moth or mosquito takes up residence in your vehicle with you. You can always avoid that with mosquito repellant bracelets. You can also use a mesh cover over your window. A ShadeSox sunshade will keep bugs out and the breeze in.
Your car is a free and easy place to get a full night’s rest. According to a survey by KOA, 93.8 million Americans consider themselves campers. You can do it for recreation. You can do it out of necessity.
Whatever your reason for doing it, it’s perfectly safe to sleep overnight in your car, even with the windows rolled up. It all depends on your personal comfort level. Go out there and play hard, then sleep harder – in your car! You’re in good company.