We thought we’d whip up a quick article on ways to increase the comfort sleeping temperature of your sleeping bag. In other words make your sleeping bag warmer. As you know we like to carry the minimum which means that for the coldest conditions we camp in we will be wearing and using everything we carry.
We travel for extended periods of time (years) so this would usually only be a couple of weeks at a time otherwise we would just come better prepared.
First it’s important to understand that most of the methods below do not actually ‘warm’ you up but reduce the loss of heat. Thats why its important that your body is properly fueled and your body is generating heat as a sleeping bag merely insulates body heat. Much like pouring cold water into an insulated flask doesn’t produce hot water.
Using the tips below we’ve used our 0 C sleeping bags and been relatively comfortable in negative conditions in Mongolia and Patagonia.
Finally, we use organic down sleeping bags from Tundra as, well they are organic so nicer on the ducks and down packs away a lot smaller than synthetic equivalents.
Here are our tips
- Thermal Liner
Thermal liners are great because not only can you use them to make your sleeping bag warmer but you can also use them in hostels in warm conditions when you’re not too sure how clean the sheets are. Before travelling with camping gear I would always bring a silk liner like this. These days as we knew we would be camping in Patagonia we changed our liners to heavier insulated sleeping bag warmers, we carry the Sea to Summit Reactor Extreme Thermalite Liner.
- Decent Sleeping Mat
Don’t underestimate how important a decent sleeping mat is. The old school yoga style camping mats just don’t cut it in terms of comfort and also keeping you insulated from the ground. Lightweight Air pads are small, thin air mattresses suitable for backpacking. Make sure you check the R rating of the pad which is the measure of how well it insulates. We currently use Expeds Synmat Duo a pad for two people but we’ve also used Thermarests Light and Fast range as well. They are an investment but your sleeping bag is useless without it.
- Wear More Clothes
It's a myth that sleeping naked in a sleeping bag is warmer than in thermal underwear. Wearing good thermal underwear or even more dry clothes will keep you warmer at night. Our thermals are a mix of Smartwool and Icebreaker merino wool. If it's really cold we’ll even wear our down jackets and wooly hats. As long as your clothes are dry and you aren’t compressing the insulation of the sleeping bag it's good practice to a better night's sleep.
- Jacket Over The Bag
You can’t wear all your clothes in your sleeping bag and if you wear your waterproof to sleep its usually not comfortable because of the crinkling and all the zips digging into you. One thing you can do is slide the zipped up waterproof over the bottom of the sleeping bag to create another layer and increase the warmth over your lower legs. Alternatively drape your jacket or other clothes like a blanket over the sleeping bag. The only problem with this is you won’t be able to move too much in your bag.
- Bin Bag Over The Bottom
This follows the same principles as the above tip, you slide the bin bag over the bottom of the sleeping bag. However, I would only use this in extreme conditions as often condensation can build up. If your sleeping bag contains down and doesn’t have a slight waterproof coating then this will have an adverse affect as down doesn’t work when it's wet.
- Hot Stones
This is a technique we used regularly in Mongolia when we were travelling with our animals. Every night we would be cooking on dung or wood fires and would throw a couple of large mango sized rocks into the fire. About 30 mins before we would go to sleep we would bring them out of the fire, let them cool and then wrap them in our towel or an old sock to bring to bed with us. Just be very careful as they can get really hot but if you get it right it will keep you warm into the early morning.
- Hot Water Bottle
We've recently started experimenting with travel size hot water bottles and found them to be really good if you’re camping in cold climates. We often cook pasta when camping and would just throw out the hot water after cooking. Now we pour the pasta hot water into the hot water bottle and wrap the bottle in a winter buff and have a hot water bottle with minimum fuss. Alternatively you can use a Nalgene with a similar effect.
- Cover Head
That old saying that you lose most of your body heat from your head, well there is some truth in it. The truth being that if you cover all your body and not your head of course you’re going to lose the most heat there. If you’re one of those people who must have air on their face and not buried into the sleeping bag then make sure you cover your head.
- Foil on Footprint
If you’re using a footprint with your tent then consider lining it with some foil. Foil is a great insulator and we’ve seen people doing this in Patagonia. They claim it keeps you that little bit warmer and also stops water from the ground seeping through. Making your own footprint isn’t hard, here's some instructions.
10. Body Warmth
Get to know your partner, spooning is a great way to share the body warmth. If you’re a couple consider buying sleeping bags that zip together to further increase the efficiency of shared body warmth. On a side note, sleeping on your side will decrease the amount of contact with the floor and reduce heat loss.
11. One Extra Tip
If you’ve read this far then you deserve the most important tip. As mentioned at the start of the article sleeping bags insulate and keep warmth in. So make sure your body is well fueled with food before you sleep so that it can produce heat. Similarly doing a few burpees or star jumps to raise the temperature but not sweat will warm the muscles.
We would love to hear your tips in the comments below.
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