
NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.

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I've had one-pound, western mtering bag "highlite" for many years. ... I'd prefer a longer and heavier zipper and also wider dimension for wearing more clothes to bed. It's rated at 35F, but this is wildly optimistic for cold sleepers. I've used it at 25F, w/ lots of clothing. Is ok bag at high price.
I use Western bags, and they're awesome, but wanted to go lighter, so I switched to a Zpacks bag for my cold weather bag. I found that Zpacks bags are truer to their temp ratings. I still use the Western HighLite for my warm weather bag, but now use the Zpacks Classic bag for cold weather. Their Classic 10 deg bag only weighs 20.5 oz and the Classic 20 deg bag only weighs 16.6 oz. I can't say enough about Zpacks: https://zpacks.com/collections/sleeping-bags
I've had wm highlight for 20 yrs or so. Lately added "cheap" down pants & jacket. But I'd rather have the 10F model for below freezing. Definitely thought of retro-fitting a full zipper for warmer weather. Was never super happy with the bag but sm too poor to replace.
That's a very good deal & nice bag...(how is a full-zip "bag" less warm than quilt!??) I've used the similar Western Mtnr "HiLight" model for years &don't really like it (too tight; zipper too short) but I'm too poor now, to replace. Pushing a "summer bag" to freezing or a bit below is always "possible." At their best on balmy nights (as "quilt").
WM has 3-4 "semi rectangular" models rated from 40F to 25F. "Only bag I know that no one has ever complained about being cold." I have a non-semi-rectagular, WM 40F bag that prompted my complaint around 50F. But have used it as low as 25F wearing supplemental clothing. Nice stuff; not necessarily worth the frightening price.
If you are brand new, get something cheap and on sale. Fair chance that you either will give up backpacking after a few trips or realize that you want to invest more in high-end gear. You eventually need a quiver if tents, sleeping bags, and packs as no single one is great for all conditions. For summer, I mainly use: flycreek 2p tent, Western Mountaineering 20 or 40F sleeping bags, and a daypack with side straps that cost about $60 and weighs roughly half a pound.
Western Mountaineering mummy bag. I do a lot in shoulder season and these are very warm for the weight
I am a cold sleeper too. And I’m embarrassed to admit, I could afford a western mountaineering bag. It was 0°. And I’m 59 and I got the 6 foot six version. Giving me tons of down to snuggle into. I actually use this bag way more than just the winter and I’m always toasty warm.
Western mountaineering. I get cold easily even in the summer in Colorado at high altitudes. I also snow camp
Don’t forget to get a really big bag one that goes way over your head. It’s just so cozy.
It really depends who you are. I can shiver on a Colorado summer night at 11k. So I spent 2lbs on a western mountaineering bag. I love it.

NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.
Hammock Gear
Classic Burrow 20°F
Budget-friendly quilt; very warm, but not ultralight.

NEMO
Disco 30
Roomy spoon shape, but bulky and prone to zipper snags.

Katabatic Gear
Alsek 22°F Quilt
Premium quality, very warm, but high price for weight.

Neve Gear
Waratah
Great warmth-to-weight and value, but untreated down.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
Ranked #1
Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series
Ranked #1
Hammock Gear - Classic Burrow 20°F

Ranked #1
NEMO - Disco 15 Series