For all their convenience, zippers are heavy and somewhat prone to failure. In full sleeping bag lengths, they can often add a full ounce to your sleep system. They can snag and pull on the ultralight fabrics making it necessary to reinforce the area around it, further adding to the extra weight. Lastly, they require draft tubes or some sort of system to cover over the uninsulated area where the zipper is….and of course, it isn’t all that uncommon for them to fail. On a camping quilt, we just get rid of it, along with the whole bottom of the bag, which is redundant weight, but there are often draft issues that need to be dealt with. However, the false bottom bag design provides a fully draft-free system without the complication/weight of zippers. Venting a false bottom system is a bit different but not as limiting as one might think. First, the top drawstring can be used for primary upper body venting by opening it to allow heat to escape or by sticking an arm out. After that, it can be fully pulled down off a sleeper’s core. Additionally, the false bottom of these bags can be spun around to the side or top, allowing heat to escape through the single layer fabric without exposing the body to the outside, a bit like sleeping under a sheet on a hot summer night. Beyond all this, a sleeper can get out of the bag entirely and drape it over themselves as needed on hot nights. It is quite common for folks to have some anxiety around venting simple bags, but after some use, the feedback is unanimously positive. It takes slightly more effort to push out the top drawcord than to just push back a camping quilt and you can’t just stick a leg out like a quilt, but it’s actually quite easy to regulate heat in a false bottom bag. The draft-free performance in cold weather heavily outweighs any extra effort required in warm weather venting.