
NEMO
Disco 15 Series
Spacious spoon shape, but bulky and inconsistent warmth.
Running these analyses costs money. Buy through my links to help keep lights on! I may get a small commission.
I used a Wiggys bag when I lived in Alaska, as did almost all of my scout troop. Most of us had their -40 2 bag system. I never had it down that cold but definitely got down to -10 to -20 range with no issues.
They also sell compression sacks. With a sitting on it and pulling the straps. I get it squished down pretty small. But you’re right. They don’t pack down extremely small. My favorite wiggys is this one. https://www.wiggys.com/specials/hunter-super-light-with-hood-rectangular-sleeping-bag/ It’s 6lbs. Rated to 0 degrees. But 0 degrees of happiness and warmth not survival. It packs down very small. The size of a basketball with a compression sacks. My wife also uses it but she runs cold. She uses an additional blanket or comforter and she’s happy and warm.
Wiggys.com They make custom sleeping bags that aren’t crazy expensive. I’m 6-5 and 300lbs. I sleep all spread out like a starfish. They made me a huge custom sleeping bags 4 actually over the years as I needed heavy weight for -20 conditions, then 3 more for various temperatures and backpacking ultralight.
Wiggys.com They have long bags and will make custom ones if you need a wider size. Great quality and you will love the bag forever.
Wool socks, insulated Danner boots, synthetic long underwear, synthetic boxer briefs, long sleeve cotton shirt, wool flannel mix shirt, synthetic rain parka, balaclava, baseball hat. Add a sleeping bag from wiggys.com And you’re good down to 15 degrees Fahrenheit. Eat red meat and get lots of iron. If you are vegan. Eat spinach and kale. Are you talking colder?
I have a military sleep system that I've replaced the cold weather bag with a Wiggy's zero degree bag, I've slept down to 20 degree's with no issue and I'm sure it would go lower than that.
Wiggys has some excellent 0F or 20F rated sleeping bags for $112-125 on special (discounted price + stuff sack + pillow + free ground shipping to Lower 48). Made in Grand Junction Colorado from US materials. They loft and insulate like down but don't absorb moisture and can be stored compressed indefinitely without losing loft / insulation. The other nice thing is they come in different sizes, so you can order a bag that fits you better (less volume = faster to warm up). Quality as also top notch, they make sleeping bags and winter survival clothing for the Air Force and Air Guard crews up here in Alaska.
Wiggy bags out of grand junction Colorado I slept cold with every fancy ‘outdoor’ brand bag until I was 20. My dad had been using wiggy bags for a decade at that point and I finally switched after having to cut a fishing trip short due to lack of sleep from the cold. Bought a wiggy bag when I got home. Have been sleeping warm for the last 29 years. All of my friends that have made the switch say thank you for the recommendation.
Wiggy sleeping bag. High r value pad like a thick exped. Ignik heated pad cover if you have power. Sleep in clothes so you don’t get cold taking them off then cold again putting them back on in the AM. Get super organized so you’re not wasting time dicking about. Things that you don’t mind doing in summer warmth can get really annoying really quickly in the cold.
Wiggys sleeping bags are amazing, though not the smallest ever. I would want one in a war zone.

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