ueli just says no …

On the simple point of no zippers:

Absolutely, this saves weight and makes for a more insulative bag. And it packs smaller. Is it REALLY less versatile? Do you overheat in moderate temps? I'd argue we can get used to sleeping on anything. The Chinese used to use stone blocks as pillows. I used to use sheet-blanket-comforter adjusting the combo to the temps, but my wife wanted a single, thick down quilt. I learned to deal. I toss some of it off my shoulders or feet and that works, unconsciously, for me now.

As for the OTHER reason for zippered bags: when most Everrest climbers are married (or domestic) partners, THEN let's go back to zippers.

Second point on Zippers: When working in a BP shop, we'd order equal numbers of R and L bags. When we were a little heavy on L bags, I'd point out to customers (accurately) that far more people had R bags and if they wanted to maximize the possibilities, they'd buy a L bag.

I suspect that before getting a zipperless sleeping bag, you might want to try using your current sleeping bag without undoing the zipper. I tried it and decided I definitely want that zipper! Those of us with weak bladders (old age and childbearing here) need to be able to get out of the bag in a big hurry, which the zipper facilitates.

As usual, YMMV, HYOH, different strokes for different folks!

I tried to find the perfect pants for my PCT. Perfect meant that there were no (few) zippers, belt loops pockets etc. I ended up taking a brand new pair of REI Sahara pant and doing major surgery. Ended up loving them on my hike but they got shredded especially from glissading. So I got back and made up a new pair. I suspect that these folks are creating many of the same products that we are in the end just by different means. They are custom ordering and we are modifying.

Isn't a sleeping bag without zippers essentially a quilt?

"Essentially a quilt" would be a sleeping bag with the zipper completely open. With a no-zipper bag, you'd have a half-width quilt twice as thick.

When I can solo M9 at altitude I'll consider bags without zippers.

The only thing I imagine would be worse than getting into a zipperless bag in a hammock would be getting out of it.

PHD in the UK have been making ultralight zipless bags for a while now, and a fair few people using them without complaint. So long as the bag isn't super tight its not a real problem and the weight saving is genuinely non trivial, especially at the lighter end of the spectrum.

Cheaper to make too of course.

Zipperless bags have been around for a long time. Getting into one is no worse than getting into a zipperless bivy.

Which can still be a pain in the a**.

Especially when you're in a hurry!

Back in 2005 when I was researching lightweight gear, I saw a zipperless down bag from The North Face, called the Beehive or something similar. I believe that Vaude also had a zipperless bag at that time.

Nothing wrong with a zipperless bag if you can take your time getting in and out and aren't in a hammock or a really snug solo tent!

For those of us who can afford only one bag, which has to be warm enough for high altitude late season backpacking, a full-length zipper is worth the extra weight to ventilate on warm summer nights.

YMMV and all that!

So if you're getting into such a bag quickly, would that move be called a

Zipless Tuck?

(A bad 1970's Erica Jong pun)

A climber may not worry much about campsite comfort, though if they got the weight down, a zipperless sleeping bag could be marketed as an emergency sleeping bag I guess.

Checking out the Mountain Hardware/athletes website, their sponsored tend to be extreme climbers, extreme skiers, etc… plus a dose of Euro-style techno/trance music.

"Which can still be a pain in the a**."

Indeed. Especially if one has a larger one than normal.

Me I'm more concerned with my wide shoulders and chest then trying to shimmy down inside my bag and bivy while wrestling with my pad and puffy clothing. ;)

Then you need one of these:

http://www.backcountry.com/the-north-face-elephants-foot-sleeping-bag

I've actually used an elephants foot before. Cool idea but I didn't find it very warm for the 'normal' winter months where I hike. Truth be told I'd be fine with a partial zipper bag for the winter but once I get into three season hiking and the wide range of temps I deal with I like using a quilt or a full zippered bag for their versatility and ease of venting.

To each their own though.

I ordered a zipperless bag from PHD and used it and have no regrets. On the issue of potentially overheating simply put less of your body inside the bag. If your seeking a little less insulation than the bag for the exposed body parts then use some of your clothing.

The lack of zip then complements an airbed like the Neoair as one less sharp metal to puncture the mat.

My bag is tight on me around the shoulders but I didn't have issues getting in/out, is a little bit of feeling of weaving yourself into a cocoon but not difficult.

The only downside I could see was the unused bag at your feet was blocking venting on my tent.

I just stopped by the Mountain Hardwear store near my work this morning and saw that "Ueli's" new line of clothes has already started hitting the shelves here in Korea. From what I have seen so far they are indeed very nice but not necessarily anything that hasn't been done before. So far I have only seen the pants and the Nilas down jacket, but when the Dry Q pullover comes out I might consider picking one up to replace my current shell…

Considering Rab and other brands with lighter options don't sell anything directly in Korea it's nice to see a mainstream company offering simple and light gear in a market that loves heavy pro goretex jackets that seem to have more pockets than I have fingers.