Insulation is key
The underquilt is perhaps the most essential piece of a good hammock setup. You must stay warm to stay happy in the outdoors, and a sleeping bag just won't cut it. When in a hammock, just like on the ground, your body weight crushes the insulation in your sleeping bag underneath you. This collapsed insulation is essentially worthless. In a hammock, this lack of bottom insulation is compounded by the fact that you have air circulating beneath you. It can get cold in a hurry. Even with a 15*F sleeping bag, the cold starts creeping in as warm as 55*F.
Options for staying warm
There are two viable options for hammock insulation: a sleeping pad and an underquilt. The most common is a sleeping pad. This is a popular option because many people already have sleeping pads from tent-camping. They work similarly well in a hammock. However, sleeping pads have problems when used in a hammock. First, they do not conform well to the shape of a hammock. This can depend on the hammock and the pad, but the fit is not ideal. Second, if you move around a lot, chances are you will wake up with your pad on top of you. Third, most pads are not wide enough. Hammocks wrap around your body, and touch your shoulders and hips. Anywhere your hammock touches your body, you will experience a loss of insulation in your sleeping bag, and, thus, a cold spot. Finally, sleeping pads change the feel of a hammock, and usually not in a good way.
The Exzo underquilt is the better option. Because it wraps around the outside of the hammock, it is unaffected by your body weight, and the insulation can loft to its full thickness. For this same reason, it is seamless. You do not feel it nor does it change the shape or feel of the hammock besides the warmth that it provides. If you are serious and committed to hammock camping, the underquilt is absolutely essential.
How cold can I go?
Over the past two years, we have tested Exzo underquilts in all conditions, from 60*F humid steam-fests in the Smokies, to -5*F in the dead of winter on top of North Carolina's highest peaks. Our testers have yet to spend a cold night in a hammock. With the right underquilt, happiness is possible at any temperature. It might be surprising that even as high as 55-60*F, you will get cold without an underquilt. For an ultralight, 3-season backpacker, an underquilt like the one above would be ideal. It is good to about 20*F, but still comfortable as high as 60*F. With the lightest fabrics and best down possible, you can have a full-length, full-wrap underquilt for 15oz. Because of the full-wrap, you no longer need a full sleeping bag in the hammock, and can save more weight by going with a top quilt. Our ultralight top quilt/underquilt combo weighs in at a scant 33oz (2lbs 1oz), and is comfortable at 30*F (the top quilt is only good to 30*F). Many 30*F sleeping bags ALONE weigh more than that, and they do not address underneath insulation.
The thicker tan underquilt below has seen duty as low as -5*F, and has yet to be pushed to its limit. With further testing, it should be a solid -10*F performer. With a weight of just 28oz, ultralight hammock camping is a reality even during the winter. There are so many other products on the market that promise to add warmth, such as over covers, under covers, pod-type things, etc. At Exzo, we believe that is thinking in the wrong direction. Such covers will likely add a few degrees, and perhaps stretch you to 40*F if you were ok at 50*F before, but they will also trap moisture and cause condensation. If you want to REALLY be warm, you don't wear a windbreaker, you wear a down or synthetic insulated jacket, right? So why would a hammock be different? It's not. If you surround yourself with enough down or synthetic insulation, you will be warm at any temperature.
How do I choose my Exzo underquilt?
This is the toughest part, but you have all the answers. Here are the main questions:
- Down or Synthetic?
- Which fabric?
- What temperature?
- Full-length or Torso-length?
First, is the question of down vs. synthetic. If you don't know much about the two options, here's a quick guide. Down is unbeatable when it comes to warmth to weight ratio. If you want the lightest and most compressible quilt possible, go down, without question. However, down has one downfall. If it gets wet, it loses loft, and stops insulating. In practice, if you have a good tarp and good waterproof stuff sack for your down gear, this is not a huge concern. At the moment, we have two options: 900FP standard goose down (the highest quality down available), or 800FP Activ-Dri down (down coated with a DWR or Durable Water Repellent coating). What does all this mean? Essentially, FP, or Fill Power is the fluffiness of the down. The higher the number, the less down we need to get you to a certain warmth. That means your Exzo quilt will be lighter and more compressible. In a 20*F quilt, the difference between the two types of down would equate to roughly 1-2oz (the 900FP version being lighter). The Activ-Dri down is 800FP down that has been treated with a DWR coating that helps the down fend off moisture. It is particularly effective when it comes to dry time and accumulated moisture over long, humid trips. Synthetic insulation is made of ultra-fine polyester fibers that mimic down's ability to trap air and warmth. Synthetic insulation is not as light or compressible as down, but it retains most of its loft and warmth even when soaking wet. Currently, we have access to Climashield APEX, Primaloft Sport, and occasionally, Primaloft ONE. Synthetic insulation is also much more affordable.
Now, choose your fabric. We recommend the lightest fabric available, but it depends on your needs. Because underquilts hang under your hammock, and do not deal with much abrasion, the lightest option usually provides plenty of durability. However, accidents happen, and we have access to tons of fabric types in case you want a certain color or need added durability. There are also possibilities for wind-proof or waterproof fabrics, etc.
Temperature is the important part. Are you a summer-only Southeast backpacker, or are you snowshoeing deep into the New England wilderness in winter? You likely know what you need, but Exzo can help if not. If you want a good, catch-all temperature, go with 20*F.
Full-length vs. torso-length is likely a function of your style. If you cut the tags and excess webbing off your gear and chop your toothbrush to a nub, torso-length may work. If you value comfort and hate cold feet, go for the full-length. If your underquilt will see winter duty, full-length is best.
Pricing will be totally dependent on the materials and specifications of the underquilt Exzo designs for you, but expect a 20*F full-length, full-wrap, down-insulated, light as possible model like the grey one pictured to be around $400. Add about $100 for every 20*F below that (a 0*F would be $500, -20*F $600, etc).
If you are looking to cut costs, synthetic is the way to go. Expect a 20*F synthetic, full-length, light as possible underquilt to cost $250. Regardless of insulation material, we can cut costs to some degree by using different materials. This will add weight in most cases.