How to insulate and stay warm in hammocks

The key to staying warm in a hammock tent is finding a way to be insulated underneath.   Like camping in ground tents, you are at the mercy of the temperature beneath you.  But it’s even worse because even in the middle of a hot summer you can get frozen in a hammock when a breeze passes over water and acts like an evaporative cooler on your backside.

What provides the best insulation for hammocks?

There is only one reliable insulator: air.  Therefore, you should judge your insulation by how much air it can hold without flushing that air out when you move around in the hammock.

Pads

The best hammock insulation will conform to the bottom of the hammock without a large gap between the insulation and the hammock bed.  Pads can accomplish this, whether placed directly below your sleeping bag (or in sleeping bag sleeves such as those found in Big Agnes sleeping bags) or placed in dedicated pad sleeves below the hammock bed which some hammocks provide.  However, pads can be awkward and bulky to pack and they may not always perform well in the three dimensional world of hammocking where your body weight turns a fairly flat bed into a bathtub.  In addition, pads typically don’t breathe well, and may essentially seal the fabric below your back, making the hammock less comfortable.

Underquilts

The consensus is that insulating underquilts are superior to pads.  They breathe and are built to conform to the hammock when your weight is inside.  An underquilt must walk a fine line, keeping close to the hammock bed but not so close that your body weight flushes the air out of the insulation.

Underquilts come in various lengths.  When you purchase a half or three-quarters size underquilt, it is usually with the understanding that your legs and feet will not need as much insulation as the rest of your body.  While this is true, your heels make enough contact with the bed that you can still get cold on your feet if there is no insulation under them in frigid weather.  You may find yourself relegated to a fetal position to stay as warm as you’d like with shorter underquilts.  In addition, smaller underquilts can have trouble keeping cold air out when you move around in the hammock. For this reason, you should consider an underquilt that covers the entire bed of your hammock.

Consistent insulation for underquilts

There is one more hurdle for good insulation to overcome. In addition to trapping air and holding it close to your hammock bed, it must do so evenly and consistently.  Otherwise, one part of your body may be a few degrees warmer than another part of your body.  Even if both areas are in an acceptable range of warmth, you will go crazy at around 3:00 am just from the small disparity in temperature.  You will desperately desire for your thigh to be the same temperature are your upper back.

Staying warm in a hammock when temperatures are between 32° F and 65° F (0° to 18° C)

It is very frustrating to think that most hammock manufacturers expect you to bring insulation with you on almost every trip, since most people end up in temperatures below 65° F (18° C).  Clark stands out from the crowd here with its four-season hammock like called the NX Series.  These hammocks have built-in pockets that, when holding gear or other items, hold out a dead air space underneath the heaviest parts of your body where you compress you sleeping bag the most.  Cold breezes are then unable to affect you.  The insulating pockets on the newest Clark NX models are sewn shut on the outside, with only interior access from zippers on the inside of the hammock.  This means that it’s easier to keep cold air from seeping in and disrupting the stable air mass that your body is warming.  These pockets are intended to keep you from having to bring a pad or underquilt on typical camp-outs where you are expecting good weather and when you don’t expect temperatures to dip below 40° F (5° C).

Down vs. Synthetic underquilts

If you are not allergic to down, then purchasing a down underquilt can be a good value since they pack tighter than synthetic and are more durable over time.  However, they also cost significantly more and will not insulate you if they get wet.

Conclusion

Clark is the leader in cold-weather hammocking.  NX models provide built-in insulation that keeps you from having to bring a pad or underquilt on most trips.  They include built-in velcro to atttach full-length underquilts (called Z-Liners) that provide even and consistent warmth and can allow you to sleep down to 0° F (-17° C) if you have decent coverage inside the hammock (a sleeping bag meant for the temperatures you are sleeping in is recommended).  Because Clark underquilts attach with velcro, they effectively seal out cold and won’t flush out a lot of warm air when you move around the hammock bed. Because Clark Z-Liner underquilts use the highest grade synthetic fill (ClimaShield Apex), they pack almost as tight as down and will work even if they get wet.  Finally, you can install Clark underquilts on the hammock and pack them in a larger stuff sack that comes with the underquilt.  After all, when your fingers are already cold, the last thing you want to do is attach an underquilt when arriving at your campsite.

Hammock Tarps – How to choose

When choosing a hammock tarp, start with the obvious: it needs to keep you dry.  Not all hammock tarps can do that reliably, sometimes because they are made in an inferior way from poor materials.  But usually it’s because of the shape of the tarp itself.  Another consideration is the ability of a tarp to protect from blowing rain and shed wind.

Hammock Tarp Shapes

Many hammock tarps on the market today are diamond-shaped.  It’s easy to see why.  First, they look really cool.  Plus, it’s much less expensive to produce a diamond-shaped tarp because the triangular pieces allow the manufacturer to use much less fabric and save money.

The problem with diamond-shaped tarps is that they don’t protect a hammock very well, unless the rain happens to be falling straight down.  When blowing rain begins, a hammock camper will find that a diamond-shaped tarp has little protection anywhere but over the middle of the hammock bed.  The result is that the areas near the occupant’s head are far less protected.

Rectangular shaped tarps are also common, and protect better than diamond-shaped tarps.  But rectangular tarps are also not created equal.   These tarps have a tendency to flap noisily in the wind.  This is caused because the outline of the hammock between the tie-out points are straight.   Superior tarps are cut with curves between tie-out points to allow the hammock to shed wind and not keep you up all night listening to violent tarp flapping.

Materials for building hammock tarps

There are various fabrics and other materials used to make hammock tarps.  The most popular is sil-nylon, a silicone impregnated or coated nylon fabric.

Sil-nylon is lighter than many other materials because the silicone coating itself is lighter than other coatings used to make nylon fabrics waterproof.  In fact, it hardly adds any weight to the fabric at all.  While much more expensive than polyurethane-coated fabrics, sil-nylon is definitely worth the price.

Another material sometimes used for hammock tarps is Cuben Fiber.  Cuben Fiber is taken from the sailing and wind-surfing industry.  It is a laminated fabric that is extremely lightweight.  However, it is also more expensive than sil-nylon.

The current consensus is that sil-nylon makes more sense for hammock camping based on its price, its ability to be cut with catenary curves, and the fact that it blocks more light than cuben fiber.  If a cuben fiber tarp is not cut to shed wind correctly, it is extremely noisy.

Solution

Clark, the inventor of the camping hammock, makes sil-nylon hammock tarps that are both protective and include wind-shedding catenary curves to help you sleep better.  You also get velcro closures on each end of the hammock for ultimate protection in violent storms.  Besides the tie out point on each side of the ridgeline, Clark tarps offer you three tie-out points on each side that create a reliable, waterproof shelter.

If you want to sleep well in a hammock, make sure you have the right hammock tarp, not just a cool tarp made on the cheap.

What hammock features do I need?

Most hammocks are comfortable.  But that doesn’t mean they are all created equal.  When purchasing a hammock tent, take time to determine what features you need for the type of adventures you are planning.

Above all, take these items into consideration:

  1. What is the lowest temperature I plan to sleep in?
  2. What is the highest temperature I plan to sleep in?
  3. How important is good mosquito protection?
  4. How much awning do I want my tarp to provide for activities around the hammock on rainy days?
  5. What is my primary sleeping position (side, back or stomach)?
  6. What weight threshold would I like my combined shelter, insulation and sleeping bag to stay under?
  7. How long do I need my hammock to last?
  8. How do I wish to store my gear when sleeping in my hammock?
  9. Do I want to share my hammock with another person?

If weight is your only concern, you will be able to find many hammocks that are extremely light.  But that also means that you’ll sacrifice durability.  It also means that you may not have adequate coverage from your rain tarp.

Be aware that some kinds of added weight to a hammock can actually save weight in other areas.  For example, the four season hammock models by Clark include insulating pockets that (when used properly) can save you from having to bring any other insulation on trips that are above 32 degrees F (0 degrees C).   And when you add an underquilt (such as the Z-Liners made by Clark) you can save weight by purchasing a sleeping bag that has no under-insulation (such as those made by Big Agnes).

If you are most worried about high temperatures and mosquitoes, it’s best to get a hammock that allows breathability while keeping mosquitoes off your back.  The best example of this type of jungle hammock is the Clark TX-270, which has a breathable bottom that is mosquito-proof against all of the world’s mosquitoes.  This feature adds weight to the shelter, but for complete protection, it is worth it.

If you hope to share your hammock with another person, decide whether you are okay being forced together all night long in one big hammock bed, or if you need two separate beds that give each of you your space (see the Clark Vertex and Double V hammocks).

Clark hammocks are built for the long haul with the features that keep you comfortable when weather and terrain are at their worst.  See the unique features that make Clark hammocks the envy of the industry.