I just got into ultralight backpacking i need a good low cost bivy for my sleeping system any suggestions?
-Nate-

P.S. I need the weight to be under 24 ounces.

The REI Minimalist bivy sack: $100, 15 ounces. The only drawback is that the mesh face opening isn't backed by a rain flap, so if you plan to use it in lots of rain, you'll need to use it with a small tarp (6x8 is large enough, anything larger is a palace); silnylon would hold the weight of the entire system to about a pound, but will run the cost up. However, if you use a poncho for raingear, it can double as a tarp (and save a bunch of money and weight over waterproof-breathable.) Sea to Summit makes a really nice one, designed to double as a shelter.

Again, as in your question about the sleeping bag, you have provided no information about yourself or under what conditions you'll be using it. That makes it difficult if not impossible to suggest anything for you.

One basic problem with waterproof bivies is that there is inevitably a lot of condensation inside, especially in cold wet weather, which will ultimately collapse your sleeping bag insulation. That's because your body puts out a lot of moisture while you're sleeping which can't escape through the waterproof bivy coating. Such bivies are really designed for emergency bivouacs (as when mountaineering) rather than regular nightly camping. Since you need a tarp with the bivy anyway to keep rain from pouring in while you get in and out of the bivy, a waterproof breathable bivy (which lets your body's moisture escape) with a tarp is generally considered a better solution. Most WPB bivies run about 6-8 ounces. Mountain Laurel Designs makes some good ones. Equinox makes the cheapest, which is adequate if your body is relatively slender.

Some feel that it is both cheaper and lighter just to have a larger tarp, big enough that you can snug it down to avoid rain splash, and dispense with a bivy altogether. Ron Moak of Six Moon Designs is of this opinion and has an article advocating this on his website. Not everyone agrees, of course. It's pretty easy to experiment with a cheap plastic tarp to decide which you prefer.

The basic problem with using a poncho as both raingear and shelter is if you have any reason to leave the shelter while it's still raining. This would be a big problem for me, but not for all. If you can stay put underneath the shelter overnight, no issues. There is the issue of having to hang your food after dinner, though--some solve this by stopping for dinner early and then hiking another hour or two before making camp. You'll need to hang your food before you set up the poncho for shelter.

I'd always thought the same thing about using a poncho for both raingear and shelter - how do you get out?

Then a friend showed how men can solve that problem: a "pee" bottle - prefereably a different brand, color, and opening size from your water bottle. (For example, if Platypus is your water bottle, Nalgene or Gatorade would be your "pee" bottle.)

For women, the problem remains, as best as I can figure.

By the way, the Minimalist is a waterproof-breathable bag. I used it for a year, including summer - not really a great experience, due to heat buildup in Ohio valley humidity. Other than that, it worked really well, and I'd recommend it highly. Of course, once lightweight solo tents came out (first the Hubba, then a succession of lighter tents and the revolutionary Tarptents) - for about the same weight as a tarp and bivy, a solo tent is a much better option in both comfort and convenience.

I agree with OM. There are very different types of bivies that serve different purposes. It's important to know just what you do and do not expect from a bivy and how you'll use it.

I have a full-on waterproof and heavy bivy that I almost never use; my daughter is in Search & Rescue and she uses it once in a blue moon now. I also have a much much lighter water "resistant" bivy meant to augment something like a poncho tarp adding some water resistance, warmth, and bug protection.

The difference between the two is night and day.

One alternative is to also carry a 1-ounce "emergency poncho" --- you have to search for something like this, and it's not meant for extended use, but can be used if you need to move around camp in the rain.

Pee bottle: on trips where I'm not sharing a tent or camping close to others, I'm a fan --- great in lots of rain, cold, or fierce bugs. There ARE options along this line for women. Obviously I have no direct experience, but a simple web search will turn up options.

You mentioned heat buildup in humidity in a bivy. While on occasion I love the ability to tuck into small places with a bivy, it's that sort of thing that drove me away for the most part. I recall one nice evening where the bugs were fierce yet it was just too warm to be in the bivy, even if on top of and not inside my sleeping bag.

For me, a water *resistant* very light bivy can be a good augment to a minimal shelter, particularly in shoulder season hiking, and that's about it. Note, however, that I'm a pretty indifferent (and infrequent) mountain climber.

Or a trash bag.

As a female, I get rather jealous of you men and your pee bottles. The aged bladder and my anatomy dictate that I have no choice but to crawl outside into the cold several times a night. At least on a clear night I get to admire the moon and stars. Plus I save the weight of the bottle! I've tried the various options suggested for women to overcome the anatomical differences, and I can tell you that they all leak!

There's an ancient joke about a woman camper taking a coffee can to bed with her, only to find after using it that it was upside down....