Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Tuesday, March 18, 2014

A Simple, Inexpensive, Lightweight, Effective Accessory to Control Condensation in a Single Wall Shelter

By Will Rietveld

Ultralight backpackers love a single wall shelter because they save a lot of weight and (to them) function effectively to provide all the weather protection needed.

Lightweight backpackers disdain them because of condensation. “Yuck! The tent walls are all wet in the morning, and if I brush against them, I will get wet.” How terrible! Therefore they gotta have a double wall tent; no matter that it weighs one-third more, and costs more.

I have a hard time understanding lightweight backpackers; they want to reduce pack weight but somehow manage to shoot themselves in the foot every time :).

Somehow they fail to notice that a double wall tent gets condensation on the inside of the fly, so it’s just as wet. And that brings up another strange behavior of lightweight backpackers – they wait for the tent to dry out in the morning before they pack it up and get going. That can take hours in cool morning temperatures and high humidity. Direct sun is needed to dry out a tent.

Fortunately there is a simple, inexpensive, lightweight, effective accessory that fixes the condensation problem. It’s something everyone can carry in their pack for this purpose, and many others. It’s easy to obtain and easy to use. It works great for single wall tents, but is harder to use on double wall tents because the condensation is harder to get to. 

After use, the tent walls are mostly dry, and one can decide whether to pack up the shelter mostly dry and get on the trail (a good choice), or let it stand while eating breakfast so it dries some more. Actually, with this accessory, you are better off to use a single wall tent, because you end up with a dry tent faster in the morning. Whereas if you use a double wall tent your choices are to pack it up wet, or wait it out for the tent to dry.

This accessory costs only about $10, but you can probably find a cheaper substitute, and it’s readily available at most outdoor stores or online. The weight is about one ounce, and it can be used multiple times. Single wall tent manufacturers ought to provide this accessory with each tent purchase, just to enlighten people. Frankly, when you find out what it is, it will seem like a lightbulb moment.

Well, here it is, it’s a pack towel! Yep, that’s all you need to control condensation in a single wall tent. Simply wipe down the tent walls in the morning. Problem solved. You don’t need to pack up a wet (heavier) shelter that may wet other things in your pack. And, like I said, it’s harder to use this accessory on a double wall tent, so a single wall shelter is actually better.
 Okay lightweight backpackers, here is your chance to do something right and actually save weight; get a single wall shelter plus a pack towel!


  1. Nerdy devil's advocate alert: Weight of Nano Pack Towl is 0.9 oz. Weight of SUL Cuben Fiber is .34 oz/sq. yd. Once could feasibly own a single wall shelter that containing 2.64 more yards of fabric in trade for the weight of the towel thereby making it large enough not to have to worry about brushing against the shelter wall.

    1. Hi Sam. You're right, one can get a bigger roomier shelter by going to Cuben Fiber. But the condensation issue is the same. Its nice not to brush against it as easily, but its also nice to wipe the walls down in the morning so you don't have to pack it up wet and carry that extra water weight all day. I will bet the moisture weights more than 0.9 ounce :) One could use a bandana to wipe down the tent walls, which is a multi-purpose item that can be used for other things, like a bandana.

    2. Pack Towel/bandana/sock/shirt is dual use, that extra 0.9oz of tent is not.

  2. > I will bet the moisture weights more than 0.9 ounce :)

    Touche, Will. Touche!

  3. Ok what ultralighter caries a pack towel? Bandanas rule.

  4. Per comment: "You don’t need to pack up a wet (heavier) shelter..." Weight of (dry tent + wet pack towel) = (wet tent + no pack towel). I'll concede the towel can hang on the outside of your pack and dry as you hike...

    1. Oooh you got me on the weight issue, and I would also personally choose a bandana over a pack towel. But it is still nice to mop up as much of the condensation as possible before packing up a shelter, then dry out the bandana on the outside of my pack. I have had shelters so wet in the morning, including double-wall tents, that I could probably mop up and wring out a cup of water. And that is probably the big turn-off re SW tents for some backpackers. I just wanted to make the point that condensation doesn't have to be a big issue; you can simply wipe the tent walls.

  5. disposable dish towels like clorox handi-wipes are featherweight, absorbant, reusable and even washable

  6. If there is condensation on the inside of your tent, there is excess moisture in the air inside your tent. This excess moisture will cause you to sleep colder, and it will be absorbed by much of your clothing and sleeping bag. This is especially true of down sleeping bags. These items will need to dry during the day, which doesn't happen inside of a backpack. The tent and packtowel or bandana will also need to dry.

    Good ventilation is more important than the annoyance of water on the fabric of your tent in the morning. You are correct that well-ventilated tents are typically relatively heavy. Well designed tarps, on the other hand, have adjustable ventilation, allowing less ventilation in windy conditions and more in a rainstorm, when almost no tent will stay dry inside due to condensation. I prefer the Jardine designed tarp, but there are others that are light and adjustable as well.

    That said, I love my single-wall tent for winter use.

  7. You all are right guys on your way of discussion because you all have presented your point of view regarding this topic.

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