Staying warm involves a combination of factors including insulation (clothes, sleeping bags, quilts, etc.), generating body heat from consumption of food (calories), physical activity and external heat sources. The focus of this article will be on staying warm while sleeping in a hammock so the physical activity contribution will be minimal, unless you’re a really restless sleeper. Further, everyone’s metabolic rate is different. Some people are warmer (or colder) sleepers than others. There is no one size fits all solution to the problem of saying warm. Each person will have to apply the principles and ideas discussed in this article to their own situation.
First it is important to understand the perspective of the authors. We are ultra-light backpackers who are conservative in risk taking. We strive for 12 pound base pack weights (no consumables: food, water and fuel) in summer and 15 pound base weight in the winter. We believe for example in a well stocked first aid kit of about 8 ounces. We believe that almost every item in the pack should have multiple uses. Also, we believe that almost every item in the pack should be routinely used on a daily basis. We are hammock hangers who hike all year and have not “gone to ground” since early in 2003. We have refined our style and our loads to provide comfort and warmth within these parameters.
Before going out on a backpacking trip, check the weather forecast. It is important to know what kind of weather to expect in order to guide the selection of the equipment and clothing you might need during the course of the outing. Generally we try to carry sufficient protection for one “level” harsher than the forecast conditions. Call that our safety margin.
If you want to stay warm – Eat, eat, eat! You’ve got to stoke the furnace. Pay attention to the types of food you bring. You need to restore the calories you burn during the day while hiking plus have plenty of remaining calories to burn while sleeping. Eat three good meals during the day and snack regularly between meals. Plan for a snack before going to bed. A snack consisting of a slow digesting food will last longer while you sleep. Hard cheese is a good option.
Slow your pace before you stop for the evening. Hike yourself dry. Don’t get stuck in the position of settling into camp with wet clothes on. Always have a dry set of clothes for the evening. This doesn’t mean carry a second set of hiking clothes. Change into dry socks, fleece long johns, and a dry t-shirt, or a fleece shirt. Whatever you’ve planned as your dry evening wear or sleeping clothes.
Remember, heat tends to escape most readily from your extremities. Therefore these are the areas to address first when trying to regulate your temperature. The balaclava is a staple in our pack and is almost always used when sleeping. An extra pair of socks, down booties, or down sleeves worn as sleep socks work for your feet and either socks or a pair of glove liners work for your hands.
For hammock hangers, keeping warm is a two plane issue. Most tend to focus on the bottom because it is the problem that is least likely to have been solved. The top, however, is the major warmth factor once bottom insulation is at least minimally provided. When cooler temperatures than your gear protects to are expected, you need to add layers or change quilts or bags just like a ground sleeper.
The Nest and No Sniveller quilts are baffled and filled with 800+ down to a thickness of 2.5 inches. Generally, this would suggest a comfort range of around 25-30 degrees. However, these quilts can be folded in half length-wise and shaken to shift down to the center. In this manner it is possible to get 3-3.5 inches of down in the center of the under quilt. This would suggest a comfort range of 20-25 degrees. There will be less fill, and therefore thickness, on the sides; but since most of the side area is above you when lying in the hammock, this is of minor consequence. The No Sniveller quilt can be similarly adjusted for top quilt use. Here the side thickness is more important, so just shift a little (3 inch center).
We have used the three season set in temperatures as low as 26 degrees. We slept comfortably in silk weight long johns and balaclavas. Usually we start to bed with wool socks but remove them after 10 minutes or so. There are a few things to be aware of: first, nylon not in contact with you is cool to cold, so shifting around you will notice cold nylon – it will warm quickly; second there can be minor air leakage at the Hennessy slit. This is minimal and is not too noticeable if the under quilt is not in the slit and the edges are tightly butted. This is not noticed when our feet are in the foot sack and top quilt material is therefore between us and the slit. Sleeping bag users will probably not notice this draft.
It is important to note that when we wore silk weight, medium weight, or winter weight fleece long johns as past conditions demanded this had not been noticed. Hence a major point, sleeping in long johns and clean dry socks is a major comfort range issue. Also we observed periods after 3:00 a.m. seemed cooler. This could have been a one or two degree drop in temperature, something that is hard to get exact with small zipper pull thermometers. We believe this is also because the evening meal was then 8 hours or more into digestion.
A word on the long johns, since we normally don’t carry spare pants or a spare t-shirt and only pack one 100 weight fleece top, the long johns are in the pack for two reasons: first to sleep in and second as our emergency clothes. They provide a warm close thermo-clime next to the body. They keep any shift in contact to cold nylon from being an issue.
Other routine supplements are the fleece Balaclava, polypropylene glove liners (summer) and convertible fleece mitten/gloves (winter). We routinely wear the balaclava when the night temperature is below 70. It is rare to wear the gloves, but they are there for the totally unexpected temperature drop. They will make a difference, too. In addition to keeping the hands warm they also add, in a minor way, to the warmth holding materiel above you.
Ok, you have eaten well, you have put on a comfortable base layer. You have shifted down to the critical areas but you need more. Consider these options.
First, fasten the Nest slit closed on itself. This will eliminate any draft issues. You will now enter from the foot end by moving the right edge of the under quilt to the left, enter, sit, lie back, and pull your legs inside. The Hennessy slit will close completely, you may even seal it, if desired, and the under quilt will return to normal because of the elastic suspension system.
If you are still carrying a pad use it. In addition to the standard mode in the hammock, the pad can be placed between the hammock and the under quilt. Both work well. Between the Hammock and Nest is more comfortable. Additionally, it will allow better dispersion of non-sensible sweat so that you are not in the damp pool of sweat as when directly on a non-breathable pad.
A space blanket can be held nicely between the Nest and hammock by the Nest, however, the Nest must be configured with its slit closed upon itself.
If you are expecting colder weather and you have the three season set use both quilts as under quilts. By doubling up you now have four layers of nylon and 4-5 inches of down under you. This can be increased by shifting down in one quilt to achieve 3-3.5 inches in the bottom and hang the second quilt normally. This produces up to 5-6 inches under you and retains 1.5-2 inches on the side. When used in this manner, always hang the No Sniveller inside the Nest. This is particularly important if you have the long model of the No Sniveller. You will need to use a sleeping bag or a top quilt such as the “Old Rag Mtn” above you.
To summarize each person will have a different metabolic rate. We sleep “neutral to warm” as opposed to “cold sleepers”. The following is our reference guide, you probable will want to adjust from it. It is intended as a starting point.
* Alternatively, shift to winter loft/weight under quilts and top quilts such as the Winter Nest, Old Rag Mtn, or Rocky Mountain Sniveller
* Alternatively shift to a warmer under quilt such as the Mt Washington