How To Stay Warm In A Hammock

Ed Speer January 2003

With snow falling and cold wind howling outside, this is an appropriate time to discuss staying warm! Sadly, many hammock enthusiasts have begrudgingly hung up their hammock and gone back to their old ways for cold weather camping. But with the proper gear and some experience, winter use of a hammock can be just as enjoyable and fun as summer use. The only question is "What gear do I need?" The good news is you probably already have most, if not all of the gear you may need.

I sleep in my hammock outdoors a lot; even at home, I'm usually set up in the back yard. As winter approaches and the temperature drops, I stay warm by adding wind blocks and additional insulations. The actual gear I use is given in the table below. Note that this gear list is a work in progress and changes as new information becomes available.

CAUTION: Cold weather camping is SERIOUS BUSINESS no mater what gear you are using. Be sure you have the gear and experience to do it right.

Since I'm a skinny old man, I probably sleep colder, and thus need more insulation, than most folks. However, you should use my gear list only as a suggestion of where to start your own experiments to find what works best for you. You should experiment in your own back yard, or similar "safe" place before venturing into the wilderness. To avoid unpleasant surprises, you should know from experience that your chosen gear will work; otherwise always have adequate backups available.

The key component in my cold-weather system is the Pea Pod Sleeping Bag, which is custom-made to go completely around the outside of the hammock. This prevents crushing the bottom insulation and thus eliminates the "cold butt syndrome" so familiar to most hammock campers. By using the Pea Pod, first as a stand-alone item, and later as the temperature drops even more, as part of a component system, I'm actually able to save pack weight over the more-conventional setup with all insulation inside the hammock.

How To Stay Warm In A Hammock using the Pea Pod

Temperature in Degrees F (no wind)

	+75	75-65	65-55	55-45	45-35	35-25	25-15	15-5
Fabric Treatment				x	x	x	x	x
Pea Pod			x	x	x	x	x	x
Sleep Pads:
1/4X22X47					x		x	x
1/2X24X54						x	x	x
Mylar Sheet						x	x	x
Inside Blanket:
Thin Sheet	X
Speer Top Blanket		X	X	X
30^o F Sleeping Bag					X	X
20^o F Sleeping Bag							X	X
Clothes:
Thermal Long johns
Lt wt					X		X	X
Med wt						X	X	X
T-Shirt
Short Sleeve	X
Long Sleeve		X	X	X
Socks
Lt wt		X	X	X			X	X
Heavy wt					X	X	X	X
Balaclava
Lt wt					X
Med wt						X	X	X

NOTES:

Pea Pod Sleeping Bag--1.6" loft, 2 lbs, rated 50^o F, synthetic insulation, DWR-treated 1.1oz/yd² ripstop nylon shell, drawstring end closures, full-length Velcro center closure, available from Speer Hammocks, Inc

Sleep Pads

1/4X22X47", 11 oz, closed cell foam

1/2X24X54", 14 oz, closed cell foam

Mylar sheet--Survival blanket, aluminum coated, 6X8', 1.8 oz

Speer Top Blanket--3.5'X6', 0.8" loft, 11 oz, synthetic insulation, DWR-treated 1.1oz/yd² ripstop nylon shell, foot pocket, available from Speer Hammocks, Inc

30^o F Sleeping Bag--3" loft, 1 lb 13 oz, down, DWR-treated 1.1oz/yd² ripstop nylon shell

20^o F Sleeping Bag--3.5" loft, 2 lb 1 oz, down, DWR-treated 1.1oz/yd² ripstop nylon shell

If this table does not print correctly, a full-page version can be found at

http://www.hammockcamping.com/Newsletters/Jan2003.htm

An alternative cold-weather system using sleeping bags and sleep pads inside the hammock is given in the table below, which comes from the book Hammock Camping: The Complete Guide To Greater Comfort, Convenience and Freedom

How To Stay Warm In A Hammock

With Inside Sleeping Bags and Sleep Pads

>75⁰F Thin cotton sheet & no sleeping pad

70-75⁰F 48⁰-rated sleeping bag & no pad

60-70⁰F 48⁰-rated sleeping bag & 1/4" pad

50-60⁰F 38⁰-rated sleeping bag & 1/4" pad

40-50⁰F 25⁰-rated sleeping bag & 1/2" pad

30-40⁰F 25⁰-rated sleeping bag & 1" pad

20-30⁰F 15⁰-rated sleeping bag & 2" pad

10-20⁰F 0⁰-rated sleeping bag & 2" pad

Fabric treatment refers to waterproof or water repellant treatments that can easily be added to hammock fabrics. Since these treatments also reduce or even block cold wind, they are part of my stay-warm system. Either silicone or DWR (Durable Water Repellant) sprays can be used. Multiple washings will remove the treatments when warm weather returns and more ventilation is needed.

Self-inflatable sleep pads work, but generally provide uneven insulation (i.e., they have cold spots). I've found that the same warmth can be achieved with thinner closed-cell foam pads that weigh less. However, a combo self-inflatable and a wide 1/4" foam pad may work fine. An inflatable pad without interior foam or down makes a poor insulator even though it may be several inches thick.

Note that most hammock users need at least 24" wide sleep pads to provide protection around the shoulders. Broad-shouldered campers will need even wider pads. However most generally available sleep pads are only 20-22" wide. A proper sleep pad is a piece of gear that a cold-weather hammock user may not already have. Thin, but wide closed-cell foam pads are recommended and can be used alone in mild temperatures or in combination with other pads (even pads otherwise too narrow) in cold conditions. These wide thin pads are not readily available at outdoor retailers; 1/4" thick pads up to 40" wide can be ordered from Speer Hammocks, Inc or Oware. Alternately, suitable 1/4" pad material can be ordered in large sheets and cut to size; check Quest Outfitters or Outdoor Wilderness Fabrics, Seattle Fabrics or The Rain Shed. Useful closed-cell foam pads 1/2"X24"X72" can be purchased at Wal-Mart (Ozark Trail Egg Crate Pad). The more durable 1/2" and 3/4" pads from Coleman are also 24" wide and may be found at select retailers (I get mine at my grocery store!).

For more information on staying warm, see Chapter 3, How to Stay Warm, in the book Hammock Camping: The Complete Guide To Greater Comfort, Convenience and Freedom

The most useful piece of gear for staying warm is the Pea Pod, which is a unique sleeping bag that goes completely around my hammock. Thus the user does not crush the bottom insulation. It is longer and wider than a normal sleeping bag so that it fits the hammock without squeezing the occupant. The Pea Pod can be fully open on top, in which case it functions as an under blanket to the hammock, or when needed it can be completely enclosed, leaving only a breather hole for expelled breath to escape. The Pea Pod often is all the insulation needed and may be the only sleeping bag carried. In cold weather, however, the Pea Pod becomes part of a component system and serves as an outer shell, while an inside blanket, such as the Speer Top Blanket or a light-weight summer sleeping bag is used inside the hammock. In even colder temps, a moderate winter bag is used with the Pea Pod.

The Pea Pod and the Top Blanket are available from Speer Hammocks, Inc.

Getting in and out of a sleeping bag while lying in a hammock is a gymnastic exercise mastered only with experience. I prefer to use my inside sleeping bag like a quilt over the top of me with my feet tucked into the foot end. This way, it's much easier to turn over or change positions. However, I can get into the sleeping bag for greater warmth when needed.

The clothes mentioned in the table above are an important part of my component system. I normally would be carrying them in my pack anyway for the conditions listed. Thermal, wicking long johns and/or fleece garments are highly recommended. Wearing one's rain suit or wind suit in addition to long johns will add a few more degrees of warmth in a sleeping bag; just watch out for condensation, which is generally insignificant.

Lastly, the aluminized Mylar sheet (survival/emergency blanket) is placed like a liner inside the Pea Pod where it rests against the outside bottom and sides of the hammock. The Mylar sheet blocks cold wind from entering the hammock, blocks warm air from escaping, and reflects a significant portion of your radiant heat back to you. Note that since the vapor-barrier Mylar sheet does not lie over the top of me, some of my body moisture can escape upward through my top blanket and through the Pea Pod if it is completely enclosed. With this set up, I've found that most, but not all, of my body moisture is carried upward and escapes through the insulation or breather hole above me. The Mylar sheet helps retain body heat without causing undo condensation. My body may be different than yours, so do try this at home first!

While I have no actual figures to support my argument, I suspect this Mylar sheet setup provides the equivalent of 5-10^o of additional warmth.

Other tips on staying warm, such as eating and drinking well, hiding from the wind, and adding dry leaves to the Pea Pod can be found in Chapter 3, How To Stay Warm, in the book Hammock Camping: The Complete Guide To Greater Comfort, Convenience and Freedom.

NOTE: As everyone knows, wind can greatly reduce the "effective" temperature, resulting in an accelerated rate of heat loss. In windy conditions, you will need to move to the right on the Pea Pod gear list above in order to maintain comfort. Depending on the temperature and the amount of wind hitting the hammock, you may have to shift one to four columns or more to the right! Since this is a potentially dangerous possibility, don't get caught unprepared. The proper skills and experience can play an important role here. Remember, if the hammock gear you have proves insufficient, it may be warmer to sleep on the ground and return to the comfort of the hammock later.

For temperatures below 5^oF--stay home! OK, just joking. It can be done, again with comfort and safety if you have the right gear. But now we're talking about some serious gear. For instance, extreme cold weather sleeping bags (rated below zero) and 2-3" thick extra-wide sleep pads are recommended. This is not my kind of camping and I have very little experience to draw on; so I will end my discussion here. I would love to hear from others who have the experience and wish to share it.

Best of luck and happy hammocking

Ed "Not To Worry" Speer

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