Have you ever woken up at home violently shivering?
If you have, you probably grabbed a few extra blankets or cranked up the thermostat and your frigid shakes were cured. But what’s the solution if the same thing happens in the middle of the woods?
The honest answer is: you’re screwed.
Instead of dealing with the treacherous cold conditions on the campsite, you may want to prepare yourself for all possible weather outcomes. I’ve put together a short guide for any temp-related eventuality in order for you to stay heated in your outdoor oasis.
Simply follow the steps, and you’ll figure out how to keep warm in a tent.
Reasons For Heat Loss
Before I dive into the tips and tricks of staying nice and toasty in your tent, it’s important to examine the actual causes of heat loss in the body.
Welcome to the quick high school science lesson: Camping Thermodynamics 101.
According to WebMD, the human body loses approximately 65% of it’s heat through radiation.
The process is similar to how the warmth of a campfire reaches your fingertips, but on a smaller scale (there’s a long scientific explanation about infrared waves, but I don’t want to put your to sleep). Typically, this process occurs in ambient temperatures lower than 68 ℉.
When your body loses heat via physical contact to another solid object, it’s called conduction.
Think about it like touching a metal chair: the warmth flows from your hot skin to the chair, giving your mind the impression that the chair is indeed cold. Note that temperature only flows from hot to cold, not from cold to hot.
For the outdoors, this occurs through contact with the Earth’s surface and your sleeping pad.
The process of losing heat from flowing air or water is known as convection. Although, the actual amount of temperature loss depends on the intensity of the supplied air or water (think the stronger the wind, the colder it feels).
Lastly, water evaporating from your skin causes your body temperature to drop. The water molecules obtain energy from the surrounding air and convert into a gaseous state via endothermic reaction, allowing your body to cool down.
Amazingly, this is why you produce sweat: your internal temperature increases, and you emit water molecules so that the process of evaporation will cool you down. Isn’t the human body amazing?
4 Steps to Stay Warm Without A Heat Source
Now that you’ve learned the different processes of heat loss, we’ll transfer some of this knowledge to the camping world, without utilizing an added heat source.
Step 1: Fuel Up
No, I’m not talking about lugging a generator onto to the campsite; I’m talking about ensuring that you are properly hydrated and nourished out in the wild.
Regulating an adequate temperature starts from within... literally.
To stay safe from the ever-changing elements, learn your body’s demands for food and energy. Health organizations recommend approximately 2 liters of water per day to maintain organ function, joint lubrication, and proper circulation.
Food intake levels are a little more widespread, so just ensure that you ingest whatever is comfortable for you (I prefer to eat a high-carb snack like a CLIF BAR before I head into my tent for the night).
Camper's tip: Before hopping into your freezing cold sleeping bag, do a few jumping jacks to raise your core temperature and get the sleeping bag warm. If in the middle of the night you wake up with the chills, you can do some sit-ups to get the blood flowing.
Step 2: Layer Up
After you’ve satisfied your hunger and thirst, the next best way to keep warm in a tent is to layer up, starting with your clothes.
If you have even an inkling of doubt that you will freeze your ass off overnight, bring plenty of warm, breathable clothes. Some popular sleeping fabrics in the outdoors include synthetics, wool, down, and silk (try to avoid cotton since it can accumulate moisture).
When it comes to other clothing, I would suggest wearing both wool socks and a wool hat to bed. When blood circulates through your body, your feet and ears are some of the last body parts to receive fresh warmth, so it’s important protect them (I would even throw on some gloves if you are prone to poor circulation).
Step 3: Make Your Bed
The next layer of protection comes from the combination of your sleeping bag and sleeping pad. The Earth’s surface is major source of heat loss, so you may want to invest in an insulated sleeping pad if you are expecting bitter conditions.
When it comes to sleeping bags, each one has a temperature rating, but the number can sometimes be misleading.
Take for example a 30 ℉ sleeping bag: this rating means that the average person will sleep comfortable down to 30 ℉, assuming they are wearing long underwear and utilizing a sleeping pad. Yet it doesn’t account for factors like metabolism, humidity, sleeping pad thickness, etc.
Plus, there is no ruling authority for this system, so a company can claim whichever temperature rating they want. Just be wary of the number alone when looking into purchasing a new sleeping bag.
You may also want to invest in a sleeping bag liner, since it can play an important part in the insulation process. Each company usually offers a liner that traps heat that your body radiates at night.
Step 4: Stay Dry
Lastly, the drier you are, the warmer you will be. While it’s not always easy to control the amount of moisture in your tent, there are a few precautions you can take to losing body heat from evaporation.
- Pitch your tent on higher ground. If it rains, you will be thankful that you didn’t wake up in a puddle.
- Pitch below a tree (or canopy of trees) as the air tends to be slightly warmer underneath a blanket of foliage.
- Ensure that the tent side with the most mesh is facing the wind. This allows a slight breeze and ventilation to replace the wet, trapped air in the tent, even if you do lose a little heat through convection.
- Place any wet clothes or gear in the vestibule (or leave them in the car). As these damp items dry, the moisture that was once trapped in the fabric evaporates, then condenses onto the tent fly, which could drip on you at night.
Staying Warm With A Heat Source
If you don’t think that the aforementioned precautionary measures just won’t suffice, there are a few additional options to keep your body warm via an external heat source.
The “hot packs” themselves won’t keep your entire body warm, but are mostly used to keep your extremities from freezing.
While there are multitude of different hand warmers on the market, I prefer to carry a couple of HotHands in my pack at all times. They are lightweight, single use, and provide several hours of warmth.
They also make a verison for your toes with an adhesive side that I like to stick to the underside of my wrists (I don’t know why I started doing this, but it always has worked).
Water Bottle Method
Utilized often for by cold backpackers, the water bottle method of heating your body preferable when you don’t have the capacity to pack a giant heater (we’ll get into that in a bit).
Simply boil water over the campfire or a gas-stove, then pour it in a Nalgene or metal water bottle. Tuck the bottle in your sleeping bag and voila, a temporary heat source. Be careful though! It’s extremely important that you let the water cool for a few minutes to avoid melting the bottle or burning yourself.
On top of that, do not use a thin, clear plastic bottle, as it the hot temperature may degrade the plastic, leading you to believe that you had an embarrassing ‘accident’ in your tent.
Hot Rocks Method
I’m going to be honest, I’ve never tried this method and don’t intend to, but rumor has it that it works. Instead of using a water bottle, some people have put large rocks in the campfire to warm them up, then carefully placed them in their tent as a makeshift heat source.
Be careful though, apparently rocks with trapped moisture may turn into a mini-bomb in the campfire (yes, it actually happens).
I’m still a little wary of this method since you can’t knowingly regulate the heat source, which can lead to one of two problems: you burn yourself or your burn a hole in your tent. On top of that, one false move and the jagged stone can put a gaping tear in the floor.
I’d rather not even touch a gas-powered heater, but if you plan on sleeping in the blistering cold of winter, it may be your only option.
One of the more popular propane-powered camping heaters on the market is the Mr. Heater Buddy. It outputs up to 9000 BTUs of heat.
NEVER USE A GAS POWERED HEATER WITHOUT READING THE MANUFACTURER'S INSTRUCTIONS.
Burning any sort of fuel produces carbon monoxide, which can be deadly in an enclosed, badly ventilated space. Like you know, a tent.
While heaters designed for camping use catalytic technology that burns without producing carbon monoxide, you should use extreme caution with these devices. Always turn it off before going to sleep. I'd recommend even staying out of the tent while the heater is turned on.
Personally, I’ll just stick with the hot water bottle.
Your Turn to Stay Warm!
Staying warm in your tent will keep your camping trips cool and relaxing. Ensure that you take precautionary measures to maintain your body temperature with proper nutrition, layering, and moisture control.
If these don’t keep you warm, you can try to add a heat source like a hand warmer, hot Nalgene Bottle, rocks from the campsite, or even a gas-powered heater.
If you follow these guidelines, you’ll be able to greet the outdoors with a warm welcome instead of letting the frigid temperatures freeze your thrill for adventure.
Jay toes the line between hiking enthusiast and vagabond as he treks across the world, soaking in it’s natural wonders. When he’s not exploring the trail, he writes articles to help guide others through their outdoor conquests.