Sleeping in a car safely when it's warm out takes little preparation. Likewise, you can sleep in a car when it's cold; however, you must be adequately prepared.
Whether by necessity or leisure, being warm is critical to being comfortable and safe while sleeping in your car.
Warm, layered clothing, proper air circulation, and tools such as heaters can keep you warm down to -30F!
Below we'll go over various techniques and some surprisingly simple tips to stay warm while sleeping in a car in all weather conditions.
Sleeping in a car while it's chilly outside
How Do I Stay Warm Sleeping in My Car?
To stay warm sleeping in your car overnight, you should have multiple layers of blankets (electric ones work, too) and layered clothes.
These will give you a comfortable cushion for your body and preserve body heat overnight.
Hand warmers are a great way to keep your fingers from freezing, and if you're planning on sleeping in your car a lot, you can insulate your car to keep the cold out.
Sleeping in a car with layered clothing
How Should You Sleep in Your Car in the Winter?
During the winter, you should be extra prepared if you plan to sleep in your car.
Take preemptive steps like bringing along lots of heavy blankets or a heavy-duty camping sleeping bag and dress for the occasion.
The temperature in your car can drop low at night, so you should insulate it using a reflective roll to preserve any heat and keep your car's interior warm.
Space blankets are a good way to keep the heat in your car.
Heavy sleeping bags for winter car camping
Helpful Products to Keep You Warm
There are two ways of staying warm in a car, and you should take advantage of both.
The first is with personal warming items―layered clothes, sleeping bags, hand warmers, and hot rocks.
Prepare by brewing a hot coffee or other warm beverage to cup your hands around, and bring some spicy food to raise your body heat.
You can also warm up the inside of the car to preserve heat with inset insulation inside the windows. These trap heat in your car, making it warmer than the outside.
Space blankets help keep the heat in and make the cold more bearable.
Drinking hot fluids while car camping in chilly weather
Can a Candle in Your Car Keep You from Freezing?
A candle isn't ideal for overnight sleeping in a car.
First, it doesn't provide anywhere near enough heat for freezing temperatures, and although it has a small benefit, there are way better options.
You also need to be wary of the fire risk since your upholstery and floor mats are flammable. If you're wrapped up in a blanket, there's an additional risk of the candle igniting the blanket.
On the other hand, a candle heater is a decent (but not sole) addition to your car to keep you warm. It helps, but it won't do the job all by itself.
Overnight Car Heater
An overnight car heater is a good idea to keep the area warm. Make sure you insulate the windows and floor to maintain the heat.
Space Blankets
Space blankets, also known as mylar blankets, can reduce up to 90% of the heat loss from the body. Although not 'cozy,' they are light and function perfectly as a middle layer in your blanket setup.
Space blanket
Hand Warmers
Hand warmers are a great addition to any trip where you're expecting cold weather, especially at night. This is because the body's extremities (like hands and feet) get cold very quickly and are more susceptible to the cold.
Hand warmers won't warm up the entire car, but they're great for keeping your hands from going numb and stiff.
Wool Blankets
Wool blankets are a great option to keep your body warm since wool traps heat so well. A nice big wool blanket is not only comfortable to sleep on, but it gives you lots of warmth at night.
Layered Clothes
Layered clothes are a must for sleeping in your car in cold conditions overnight. The more layers, the more body heat you trap. Adding a warm hat covering your ears, thick gloves, and wool socks can help protect parts of your body that get cold quickly.
Layered socks for winter car camping
Electric Blanket
Electric blankets produce heat as well as hold it in. So while they're not usually as thick as a hearty wool blanket, they're an excellent choice for staying warm.
Reflective Foam Insulation
Reflective foam insulation is a way of preventing warmth from escaping through your windows.
A lot of heat is lost through cracks in your doors and windows, so cutting reflective foam insulation to fit your windows is a great idea.
You should keep your window cracked slightly to allow for some air intake in the car.
How to Insulate Your Car
All you need to do to insulate your car is purchase a roll of reflective foam insulation and cut them to fit your windows, minus a little space at the top for cracking the window. Then, install them on the inside of your windows for insulation.
You can help insulate your car with insulation floor mats and space blankets.
Free Products for Staying Warm in Your Car
There are many free ways to stay warm in your car overnight, and some of them are dead simple.
While many of these free options are reasonable, you should consider that layering up, getting a good portable heater, and having appropriate insulation and blankets are generally the best way to stay safe in your car.
Always consider just how cold you expect it to be where you are at night to know how to prepare appropriately.
Another Person or Pet
Bringing your significant other or a friend with you is a great way to generate more body heat and keep the car warmer.
Of course, the closer two people are, the more their body heat is shared. Pets produce body heat, too, and are great for adding a little heat to the car.
Height of Car Roof
The higher your car roof, the more surface area you'll need to heat with a portable heater, and the easier it'll be for heat to escape through the roof. Consider insulating your roof to help keep your car warm.
Boiling Water
Boiling water adds heat to a car, and you can tuck a hot water bottle in your sleeping bag to help keep you warm.
Hot Rocks
Hot rocks are helpful because they hold heat well.
You may need to wrap them in a blanket depending on how hot they get, but they make great warmers for your sleeping bag or hands.
Should I Run the Heat in My Car?
You can run the heat in your car for 10 minutes or so every hour.
Any more than that, you risk breathing harmful emissions and wasting gas.
A great vehicle for sleeping in is the Toyota Prius. The Prius's engine will automatically kick in occasionally to charge its battery at night and maintain a consistent temperature in the car.
How Cold Is Too Cold to Sleep in Your Car?
At -30 degrees Fahrenheit, you start to hit the point where sleeping in your car is dangerous and ill-advised. In addition, heating your vehicle becomes a logical impossibility to preserve enough body heat, even with electric blankets or a portable heater.
Is It Warmer to Sleep in a Car or Tent?
Sleeping in a car is warmer than sleeping in a tent because a car has more natural insulation than a tent does; however, in either case, you should bundle up and insulate if you expect it to be really cold.
Can You Sleep in a Car Overnight with the Windows Up?
Sleeping in a car overnight with the windows up is safe as long as you don't have the engine running. There's enough natural oxygen exchange that it's not dangerous to have the windows up, but you can always crack the windows slightly for more airflow.
Is There a Portable Heater for Cars?
Plenty of suitable portable heaters for cars generate heat to be preserved in a car overnight.
Just make sure you're not at risk of touching your heater.
In addition, you need to source one suited for cars and follow any recommended safety guidelines listed in the user guide.
You also need a tip-over safety switch such that if the heater falls over, it will switch off.
The last thing you want is your heater to cause a fire in your car while you're fast asleep.
FAQ
How to Stay Safe Sleeping in a Car
Safety is paramount when sleeping in a car.
It would help if you first texted a friend your location before you go to sleep and give them a heads up when you're on the road again.
This check-in system helps you stay in touch, and your friend will be alerted if anything goes wrong.
Avoid parking on the side of the road so no one accidentally hits your car.
Don't leave the car on overnight for climate control.
You risk breathing toxic fumes, burning out your car battery, or wasting gas.
Your windows should be open just a crack for fresh air, but never leave them fully open.
A car tucked away at night with open windows is a welcome mat for thieves.