Keeping warm in a hammock in winter is rather simple, but knowing how to hammock backpack in the winter does take some knowledge before your first venture into the wilderness. First off lets discuss using just a sleeping bag with no pad or underquilt. If you were to take a sleeping bag and get inside it and use it for your winter hammock backpacking use, you would notice very fast your underside would get cold! This is because when compressed almost all insulation (down, primaloft, wool, etc.) lose almost all their insulation value. To make and keep warmth, particularly in a winter hammock backpacking adventure, you need fluff if you will. Squashing insulation just makes a $400 cold proof sleeping bag useless. Now there are a few methods for keeping warm, and I am going to discuss my method and other methods, so let’s get started!
Many people in the hammock backpacking/hiking game choose underquilts for the winter. Now while underquilts are great when it comes to keeping in the warmth in winter, they do not provide cushion. Now I like more cushion for the pushin, and underquilts just do not give me cushion. Now if you like to sleep in a hammock with nothing under you for padding, then an underquilt might just be the ticket. But when looking at the prices of some of these underquilts, a pad is more economical and provides cushion, what I like. Underquilts are basically a blanket which lays against the underside of your hammock and keeps the wind and all that warmth sucking weather away from your body. Companies make different type whether it be full size, half and even ¼ sized underquilt. In doing so, companies are making it a very diverse market place and customization of how you sleep with an underquilt can be very specific to whatever need you might think of or have. Underquilts are secured against the hammock is done usually with shock cord at the ends of the hammock, then you just pull the shock cord until the under quilt is nice and snug against the underside of the hammock. The fill for underquilts is diverse as well, with Primaloft and Down being the front runners. I love Down, it is light and packs up super small, but if it gets wet and it is not weather treated like DriDown, it is almost useless. But using or buying a underquilt make of a synthetic like Primaloft means having something bulkier and a little heavier. So this is, like everything else, up to your personal preference and budget.
MY RECOMMENDATIONS: Jacks ‘R’ Better, Warbonnet, Hammock Gear
The one I use in the winter is the Exped DownMate Lite 5, which is relatively lightweight and provides good warmth. Now when talking pads, you want to get the widest version possible, this will usually be the 24"+ variety. Most all sleeping pads come in a "wide" or "xl" version if you will. As you are going to need the pad to wrap around your shoulders some, as you do not want your shoulders off the pad and have them cold due to coming in contact with the bottom of the hammock. A pad like the Therm-a-Rest TrailPro can hang in there to relatively cold weather, around 20-25 degrees. Below that a second pad should be taken, something lighterweight like the Thinlight Insulation pad from Gossamer gear or the foam sleeping pads from Oware (closed cell foam ones).
This gets to the selection of pads. Taking an open cell pad with you will put you in trouble as they absorb moisture, something that is evil to a backpacker. Moisture is not something you want to play with, particularly in something you wear and use to keep warm. So using a closed cell foam pad you can combat this issue easily. As far as using the pad in the hammock, for air filled ones you only need to blow it up maybe halfway, or even less depending on which pad you get and what works for you. This allows for your body to contour to the hammock better, and gets rid of that square peg in round hole feeling that would be present if you blow up your pad the maximum levels. Experimenting is the best way, and going outside and seeing how you feel with different gear is the best way. A Exped pad and thin closed cell pad might work for me down to 5 degrees, but maybe not for you, so I cannot make any recommendations on what is 100% going to work for you, this is just based off my experience. Now an interesting item people use as well is Reflectix, something you can purchase at say Home Depot or Lowes. I have used this as a pot or mug insulator and have recently been in discussions with people about using them in hammocks. What Reflectix does is exactly what it sounds like; it reflects your heat back onto you. So using this under your body can greatly increase warmth and I have heard of people using Reflectix with great success. It is amazingly lightweight as well, so no worries on adding ounces. Just get a roll and cut it to whatever shape you want or need or just pattern it after your pad, etc.
MY RECOMMENDATIONS: Exped DownMate Lite 5, Big Agnes QCore SL, Therm-a-Rest Trail Pro, ThinLight by Gossamer Gear, Oware Closed Cell Foam Pads, Reflectix
Sleeping Bags/Top Quilts
Now that we have your underside covered, let’s talk the top of your body and keeping it warm in a hammock during winter. This is actually the easiest part. Just use a sleeping bag! Many people are taken by the top quilts and specially made items for hammocks made by great companies like Warbonnet Outdoors, Hennessy, Jack 'R' Better, etc. But in reality, especially just getting into hammocking, a sleeping bag will work fine. To this day I have never spent money on a top quilt, I just use sleeping bags I know work at certain temperature ranges. Now as to how to use it, just zip it down almost all the way, get in your hammock, slide your feet in and then drape the bag over your body. Once that is done just tuck the sides of the bag in under your sides. Now it is time for sleeping! Top quilts are a great option, if you want to spend the money, personally I like just using sleeping bags so that I have diverse gear and I might be slightly anal about it, haha. But top quilts are pretty cool, as they are made specifically for hammockers. They usually have no zipper, and are open about 75% of the way down the bag, and you do the same thing you would with a sleeping bag when you get it. The biggest benefit is not having the mummy head of a sleeping bag in your face, although I use mine as a pillow to a degree. There are so many ways to go here, again personal preference as they both work.
MY RECOMMENDATIONS: Sierra Designs, Mountain Hardwear, Valandre, Warbonnet, Jacks ‘R’ Better
Of course depending on the temperature, you might have to sleep with some layers, a hat, etc. But again, that is personal preference. Take with you warmth layers, and alternate and try out different ways in a few trips to figure out what works for you. For me, a Black Rock Gear down hat and vest or jacket work wonders in keeping me warm during most hammock winter backpacking trips. A nice set of gloves and possibly a neck warmer should be taken with, along with a few pairs of warm socks. I personally stay away from Cotton, as it is a horrible winter fabric for your main gear. I always take a shemagh with me though, which are made of Cotton. This is more for diverse use, say I need to filter junk out of water before I filter the water, I can use the shemagh, just as easily as I can wrap it around my neck for warmth. But mainly I go with Wool, Down and Synthetic materials (Polyester, Nylon, etc). I have seen that Bamboo fabric is nice as it keeps your core warm and yet in warm weather it keeps you cool. But I like to layer, so in sub 20's I use as example a FreeFly Bamboo t-shirt, Exofficio long sleeve wool midlayer, Black Rock Gear Down Hat and Black Rock Gear Down Vest, IceBreaker Hiking Lite+ Socks, Prana Bronson Pants and Possum Down Gloves. If I was going to sleep I would make sure to add accordingly to that base of clothing, like adding warmer socks for sleeping when I will be static and not moving. Basically, if certain clothing has worked for you when you went tent backpacking, it most likely will carry over to the hammock.
I wish you luck on your adventures, check back for more discussions like this from time to time.