Boost 650™ 20F/-6C Sleeping Bag

  • Boost 650™ 20F/-6C Sleeping Bag | Regular | WarmZip™ Open
  • Boost 650™ 20F/-6C Sleeping Bag | Regular | WarmZip™ Closed
  • Boost 650™ 20F/-6C Sleeping Bag | Draft Collar
  • Boost 650™ 20F/-6C Sleeping Bag | Packed | Regular Size Shown
  • Boost 650™ 20F/-6C Sleeping Bag | Regular Wide | WarmZip™ Closed
  • Boost 650™ 20F/-6C Sleeping Bag | WarmZip™ | Photo: James Barkman
  • Boost 650™ 20F/-6C Sleeping Bag | Photo: James Barkman
  • Boost 650™ 20F/-6C Sleeping Bag | Photo: James Barkman
  • Boost 650™ 20F/-6C Sleeping Bag | Photo: James Barkman
1 11

Therm-a-Rest

Boost 650™ 20F/-6C Sleeping Bag

$299.95
$299.95
Sale Out of Stock
Size
Size Chart

No Hassle,
30-Day Returns

Free Shipping
over $50

Warranty
Protection

Ultra-comfy three-season backpacking sleeping bag with adjustable shape and warmth.
  • Customizable Comfort: Enjoy the spacious freedom of the semi-rectangular bag or the cozy warmth of a mummy bag—pick the shape and temperature that keeps you comfy at night with just a zip.
  • WarmZip™ Tech: Patent-pending center zipper design zips up to reduce the bag’s internal space and tuck insulation around the sleeper to boost warmth by up to 10F/6C.
  • Multi-Use Arm Holes: Reach the WarmZip, read a book, play cards or simply ventilate—do it all while tucked into your sleeping bag for elevated livability.
  • Plush & Puffy: 650-fill, RDS-certified hydrophobic down is allocated to key areas with Zoned Insulation for refined heat efficiency and maximum coziness.
  • Eco-Conscious Materials: Shell and liner are made of GRS-certified, 100% recycled, soft-to-the-touch nylon and coated with PFAS-free water repellent.
  • Inclusive Sizing: Each length—Short, Regular, Long—is also available in a Wide width, so you get the bag you want in the fit you need.
  • Additional Features: YKK anti-snag zippers, cinchable hood, zipper draft tube, puffed draft collar, and a two-way entry zipper.
  • What's Included:

    • ✓ Compression Sack

    ✓ Storage Sack

Product Graphic
Product Award
Product Award
View full details

Description

Comfort is not ‘one size fits all’, which is why the Boost 650 empowers you to customize its shape to find your perfect balance of space and warmth. As a spacious semi-rectangular sleeping bag the Boost provides all the room you need to side sleep, shift about, spread out and relax. The semi-rectangular shape gives you considerably more internal space than a mummy bag—you’ll feel unrestricted and free to sleep in whatever position you want all night long. But more space demands more body heat to warm it up and cold isn’t comfortable. That’s where WarmZip comes in. Zipping up the WarmZip center zipper transforms the shape of the Boost 650 from a semi-rectangular bag to a thermally efficient mummy bag. It pulls the 650-fill down around your body and reduces the amount of space your body needs to heat. WarmZip gives you the power to add up to 10F/6C to the Boost’s temperature rating. Standard Therm-a-Rest features like a puffy draft collar, a draft tube along the entry zipper line and a cinchable hood round out the Boost’s bliss-inducing comfort.

We designed the Boost 650 to be comfortable when you’re falling asleep, when you’re asleep and when you’re wide awake and hanging out in your tent. The arm holes give you easy access to the WarmZip without having to use the side zipper. They also allow you to access your belongings, read a book, play cards or high-five your friends without leaving the cozy warmth of your sleeping bag. Getting too warm? Use the arm holes to ventilate or comfortably sleep with just your arms out. You can also ventilate around your torso or down by your feet with the two-way side zipper. Every zipper line on the Boost has a durable YKK anti-snag pull to eliminate annoying snags and damaging tears.

All that comfort must be bulky and heavy, right? Think again. The Boost 650 was built to backpack—we dialed in the materials and design to make it light, packable and high-performing in variable backcountry conditions. Zoned Insulation places the 650-fill hydrophobic down in key warmth-retention areas (on top, around your core and shoulders) and reduces it where it’s less efficient (on the bottom), allowing the Boost to create more warmth with less down. The shell and liner are made of 100%-recycled nylon that was handpicked for its light weight and super-soft feel. The PFAS-free DWR coating and the hydrophobic down keep the Boost warm and comfy even in wet weather.

Tech Specs

Short Short Wide Regular Regular Wide Long Long Wide
Weight 2 lb 4 oz (1021 g) 2 lb 13 oz (1274 g) 2 lb 11 oz (1205 g) 3 lb 5 oz (1515 g) 3 lb 1 oz (1398 g) 3 lb 13 oz (1737 g)
EN Comfort 32 F (0 C) 32 F (0 C) 32 F (0 C) 32 F (0 C) 32 F (0 C) 32 F (0 C)
EN Limit 20 F (-6 C) 20 F (-6 C) 20 F (-6 C) 20 F (-6 C) 20 F (-6 C) 20 F (-6 C)
EN Extreme -9 F (-23 C) -9 F (-23 C) -9 F (-23 C) -9 F (-23 C) -9 F (-23 C) -9 F (-23 C)
Fits (User Height) 66 in (168 cm) 66 in (168 cm) 72 in (183 cm) 72 in (183 cm) 78 in (198 cm) 78 in (198 cm)
Length 73 in (188 cm) 73 in (188 cm) 80 in (203 cm) 80 in (203 cm) 85 in (216 cm) 85 in (216 cm)
Girth Shoulder 63 in (160 cm) 75 in (191 cm) 64 in (163 cm) 76 in (193 cm) 65 in (165 cm) 77 in (196 cm)
Girth Hip 59 in (150 cm) 73 in (185 cm) 60 in (152 cm) 74 in (188 cm) 61 in (155 cm) 75 in (191 cm)
Girth Foot Box 61 in (155 cm) 61 in (155 cm) 61 in (155 cm) 61 in (155 cm) 61 in (155 cm) 61 in (155 cm)
Packed Dimensions 9.5 x 6.5 in (24 x 17 cm) 10 x 6.5 in (25 x 17 cm) 12.5 x 7.5 in (32 x 19 cm) 13.5 x 7.5 in (34 x 19 cm) 13 x 7.5 in (33 x 19 cm) 14.5 x 7.5 in (37 x 19 cm)
Fill Material 650-Fill Duck PFAS-Free Hydrophobic Down, RDS 650-Fill Duck PFAS-Free Hydrophobic Down, RDS 650-Fill Duck PFAS-Free Hydrophobic Down, RDS 650-Fill Duck PFAS-Free Hydrophobic Down, RDS 650-Fill Duck PFAS-Free Hydrophobic Down, RDS 650-Fill Duck PFAS-Free Hydrophobic Down, RDS
Fill Weight 1 lb 4 oz (565 g) 1 lb 11 oz (768 g) 1 lb 7 oz (649 g) 2 lb (909 g) 1 lb 10 oz (733 g) 2 lb 4 oz (1030 g)
Shell Fabric 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop
Lining Fabric 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop 20D 100% Recycled Nylon Rip Stop
Zipper Side Left Left Left Left Left Left
Color Morning Blue Morning Blue Morning Blue Morning Blue Morning Blue Morning Blue
SKU 14201 14202 14203 14204 14205 14206
Country of Origin Made in Vietnam Made in Vietnam Made in Vietnam Made in Vietnam Made in Vietnam Made in Vietnam

Video Gallery

FAQs and Documents

What is the Better Sleep Guarantee?

All Therm-a-Rest sleeping bags and quilts are also covered by our Better Sleep Guarantee. When you wake up on a Therm-a-Rest sleeping bag or quilt, we're confident you'll wake up feeling better than ever. If you are not completely satisfied, return it within three months with the original receipt of purchase and we will give you a full refund- no questions asked.

Why are Therm-a-Rest® sleeping bags so great for side sleepers?

Therm-a-Rest® sleeping bags are designed to accommodate a wide range of sleep positions. Therm-a-Rest sleeping bags are designed with extra room in the torso to allow your shoulders, elbows and hips to move freely. At the head and foot the fit is closer, keeping you warm and decreasing overall weight. In addition, the placement of our SynergyLink connectors is optimized to keep the mattress secure while you roll, yet allow the head and foot of the bag to rotate 90-degrees in either direction, following you for maximum comfort and warmth.

How warm is my sleeping bag and what is the EN/ISO Standard?

The new ISO standard has made a few updates to the previous EN rating system. All Therm-a-Rest sleeping bags have been adhering to the most updated standards and tested in our on-site cold chamber. For more info on the EN/ISO testing, head over to our blog.

Is your down ethically sourced?

Therm-a-Rest actively supports industry-wide efforts to ensure all down-filled products are made with the least harm possible. We are opposed to inhumane practices and actively work with peers across all industries to improve the treatment of geese. Our product development team plays an active role in the Outdoor Industry Association (OIA) and its Textile Exchange Materials Traceability Working Group (TEMTWG). Our team also serves on the TEMTWG Down Task Force, working to address key issues in the down and feather industry and manufacturing supply chain.

To learn more about OIA Working Groups visit: www.outdoorindustry.org/resources.working

How should I store my sleeping bag?

Sleeping bags should be stored dry and loose (not compressed) in order to extend the life of the bag. All Therm-a-Rest® sleeping bags come with a storage sack well suited for long term storage. For short-term storage or when shipping, use the compression sack to save space.

How do I clean my Therm-a-Rest® sleeping bag?

Follow the care instructions below to help maintain the high quality and extend the life of your down or synthetic Therm-a-Rest® sleeping bag.

 

Hydrophobic Down Care Instructions:

All hydrophobic down treatments wash out over time, and washing is hard on all down. Extend the life of your bag by spot cleaning with a damp sponge, and only machine washing when necessary.

Washing

Hand wash or machine wash in a large capacity, front loading washing machine, using 3 oz. of Nikwax® Down Wash™. Select cold water and a gentle/delicate cycle with two rinses. We recommend an additional spin cycle as well to extract as much water as possible before drying.

DO NOT dry clean. DO NOT bleach. DO NOT iron.

Drying

Hang dry your bag whenever possible. This can be a long process (24-48 hours or more), but this is by far the best way to get the longest life from your down. Use a well-ventilated, low-humidity environment. Hand-tease or shake out your bag gently to break-up down clumps, and flip it often to help speed the process.

If you need to dry your bag faster, tumble dry in a large dryer on low heat. As your bag gets drier, it will begin to loft and can actually fill the dryer chamber, preventing it from tumbling. This can cause hot spots and even melt the bag's shell, so check it often for overheating and visually inspect frequently to make sure it's tumbling. When you check it, feel for clumps of wet down and either shake the bag gently or hand-tease the clumps apart to redistribute down. Throwing in 3-5 tennis balls can help agitate the bag, breaking up those wet down clusters to speed dry times.

 

Nikwax® Hydrophobic Down Treatment and Re-Treatment

Use Nikwax® Down Proof™ to restore your down's hydrophobic properties. Specially formulated to renew the Nikwax Hydrophobic Down treatment, it can also be used to provide improved water-resistance to any down bag. Follow directions on the bottle.

Storage

The less time your sleeping bag is compressed, the longer it will serve you by maintaining the loft necessary to keep you warm. Store your sleeping bag loose, in a cool, dry place. If you must store it in a bag, use the extended storage sack it came in, or something even larger. Never use a waterproof bag for long-term storage.

 

Eraloft™ Insulation Care Instructions:

Washing

Hand wash or machine wash in large-capacity, front loading washing machine. Use a mild, non-detergent soap. Select cold water and a gentle cycle with two rinses.

DO NOT dry clean. DO NOT bleach. DO NOT iron.

Drying

Hang dry your bag whenever possible. This can be a long process (24-48 hours), but this is by far the best way to get the longest life from your bag. Use a well-ventilated, low-humidity environment. Unzip fully and flip it often to help speed the process.

If you need to dry your bag faster, tumble dry in a large dryer on low heat. As your bag gets drier, it will begin to loft and can actually fill the dryer chamber, preventing it from tumbling. This can cause hot spots and even melt the bag's shell, so check it often for overheating and visually inspect frequently to make sure it's tumbling.

Storage

The less time your sleeping bag is compressed, the longer it will serve you by maintaining the loft necessary to keep you warm. Store your sleeping bag loose, in a cool, dry place. If you must store it in a bag, use the extended storage sack it came in, or something even larger. Never use a waterproof bag for long-term storage.

Are Therm-a-Rest sleeping bags under warranty?

Therm-a-Rest® offers a Limited Lifetime Warranty for most products including all sleeping bags. Your sleeping bag is guaranteed without time limit against defects in materials and workmanship. We also offer repair services for damages not covered under warranty. Learn more about Therm-a-Rest® Warranty & Repair.

Why should I consider using a Therm-a-Rest quilt?

Using a quilt can save you weight, allow for multiple sleep positions and versatility to your sleep system. To learn more by checking out our blogs on Backpacking With A Quilt and Understanding The Underestimated Camp Quilt.

How do I choose the right temperature rating for me?

All Therm-a-Rest bags are tested in compliance with the EN/ISO standard. This standard helps users compare sleeping bags and quilts based on an industry-wide test. You should choose a bag that will allow you to sleep comfortably at the nighttime low you expect to experience on your trip. For unisex bags, we recommend that most men and people who sleep warmer choose a bag based on the Limit/Transition Range rating, which is the listed temperature rating in the product name. For most women and people who sleep colder, we recommend choosing based on the EN Comfort rating, which is found in our Tech Specs tab on the product page. For more info on the differences in EN/ISO ratings, head over to our blog.

What is synthetic insulation?

Our synthetic insulation uses at least 85% recycled polyester fibers to create a fill structure that is lightweight, compressible, warm and durable. The fibers are highly resistant to water and provide warmth even when wet. They also provide good wash durability, giving our synthetic fill products a long life.

What is WarmZip™?

WarmZip is a sleeping bag design innovation found on the Boost 650 that empowers you to customize the shape and warmth of your bag. It’s a zipper that runs on the top of the sleeping bag, up the center from footbox to chest. When WarmZip is open (zipped down), the bag is a spacious, semi-rectangular shape. When it’s closed (zipped up), the bag converts to a mummy shape. Closing WarmZip adds up to 10°F/6°C of warmth to the sleeping bag. To learn more, check out this post on our blog: WarmZip Sleeping Bag Temperature Ratings.

How does WarmZip™ add warmth?

WarmZip converts the sleeping bag into a more thermally efficient mummy shape, decreasing dead air inside the bag and holding the bag’s insulation closer to your body. A key WarmZip effect is pulling the insulation of a wider semi-rectangular bag into a narrower space, resulting in a thicker, and therefore warmer, layer of insulation on top of the body. For an in-depth look at the WarmZip effect, head over to our blog.

Does the Boost 650 have two EN/ISO temperature ratings?

No. The Boost 650 has one EN/ISO temperature rating, and it rates the Boost in its default, semi-rectangular shape. We exhaustively tested WarmZip and can confidently say that it adds warmth, but the data collected from those tests cannot be used to determine an EN/ISO temperature rating. For a more detailed explanation, check out this blog article: WarmZip Sleeping Bag Temperature Ratings.

Shipping and Returns

Free Shipping on Orders over $50

We offer complimentary FedEx Ground shipping for orders over $50. Learn More

Orders Shipped in 1-2 Days

We do our best to get all orders out within one business day, Monday through Friday. Learn More

No Hassle Returns

We accept returns within 30 days of purchase. All returned items must be in new condition. Please be sure no dirt, grass or pet hair is on the item you are returning. Learn More

Limited Lifetime Warranty

Every piece of Therm-a-Rest gear is designed to endure the rigors of your time in the backcountry. We offer a Limited Lifetime Warranty on all products, except electronic devices, which have a 2-year Limited Warranty. Visit our Therm-a-Rest warranty page for more info.

Portrait of our repair shop crew

  • WarmZip™

    Patent-pending center zipper allows you to choose a semi-rectangular or mummy shape, or somewhere in between. Boosts the bags warmth by up to 10F/6C when zipped up in the mummy shape.
  •

    Arm Holes

    Access the WarmZip, ventilate, read a book, play cards or high five your friends—all without leaving the warmth of your sleeping bag. Arm holes make being in your bag and living in a tent comfy and easy.

  • Humanely Sourced Down Insulation

    650-fill hydrophobic down is certified to be sourced from humanely treated waterfowl by the Responsible Down Standard (RDS).
  •

    100% Recycled Nylon

    Shell and liner are certified 100% recycled by the Global Recycle Standard. Recycled nylon is made of plastic bottles and reduces water and energy waste in the textile supply chain.

Overall rating: 4.5263157 / 5 from 19 reviews.

AI Generated Review Summary

Summary topics

Review topics: ["weight","bag","material","problem","design","feels","packs","features","zippers","ventilation","difference","night","option","hole","stuff sack"].

Review highlights

Reviews

A great bag!

"I love this bag! The armhole features are great and super handy when you don't want to get out of the warmth of your bag to get something in your tent! I love the middle zip as well that allows you to adjust the warmth of your bag. I'm 5'2, 128lbs and bought short version, it's perfect! Would definitely purchase this bag again."

— Char (5/5)

I’ve been using this for

"I’ve been using this for a couple weeks regularly and I love it!! Very cozy, and the arm holes are a 10/10 addition. The only issue I’ve come across is that the zipper will snag sometimes. Very much not a big issue though, it comes out very easily!! I would 100% recommend this. Very warm and comfortable. Also packs down really small pretty easily!"

— Amelia B. (4/5)

This sleeping bag has some

"This sleeping bag has some great features especially the zippers to allow your arms to be able to go outside the sleeping bag while staying warm inside the bag. I love the option of having more leg room on warmer nights and snuggled in on colder nights. It's great how light this sleeping bag is."

— Melody M. (5/5)

Leaked Copious Down - Had to Return - Great Design

"Returned due to leaking down. My wife spent one night in this bag and awoke utterly feathered. Some bags leak down at first, but this bag leaked down extensively. Also; there should be an option for 850 Goose Down. The bag is also heavy and could easily be redesigned with lighter rip-stop nylon and light weigh zippers. I hope that you will make improvements in fill, materials, and weight! This bag design could be greatly desired by backpackers far and wide with a few changes."

— Andy K. (1/5)

Excellent used 3 trips Applachin

"Excellent used 3 trips Applachin trail, Skyline drive, At. Excellent sleeping bag!!!!"

— scott b. (5/5)

I haven't used it in

"I haven't used it in the field yet, but it seems well built, packs small, and is very light. Simply didnt rate a 5 star because I haven't used it in the back country."

— Brian P. (4/5)

great option for backpacking and car camping

"I got this bag for a backpacking trip, and it outperformed my expectations. It might not be the lightest weight one on the market, but the features are what really did it for me. The arm zips are So Nice for reaching items while snuggled up, or for venting heat at night. The warm zip made a noticeable difference keeping me warm at 3C. Haven't used it for car camping yet, but that's the goal. Some reviewers have mentioned that the compression bag is too small; I disagree. The bag fits with a little bit of stuffing, and still compresses to about 3/4 the size of the bag."

— Kae (5/5)

Awesome

"Top notch"

— Keven L. (5/5)

I loooove this bag. It

"I loooove this bag. It is lightweight, comfortable, and super warm. I honestly feel like I would've been fine with a 30 degree bag because I mostly camp in the summer, but the big vent in the front and the arm holes make a big difference as far as cooling me off. Also. . . . . . the arm holes are super sweet. They make it so you can read a book or look at your phone before you go to bed. I've had a synthetic bag for years, and the feel and construction of this bag fell amazing. I don't backpack often anymore, but this bag is plenty light and comes with a compression sack to get it nice and small for packing. Would definitely recommend. Again, I love this bag."

— Robert A. (5/5)

Great sleeping bag, small improvements

"I got this sleeping bag specifically for the arm slits and I'm glad I did! It makes sleeping in a sleeping bag feel much more comfortable and natural. While I love this sleeping bag now, I didn't love it at first. That's because I had to order this bag twice because the first sleeping bag was delivered with a manufacturers defect on the two way zipper. The zipper was misaligned, creating a small opening near the foot of the sleeping bag, ultimately meaning that the bag couldn't close all the way. Luckily, I was able to return it and got a new one quickly (I ordered through MEC in Canada, not through Therm-a-rest). Secondly, I'm 50/50 on the shell fabric. While I appreciate the lighter weight and less bulky material of the 20D polyester, it also feels quite thin and delicate, and I'm always conscious of unintentionally or accidentally tearing or cutting it, especially when storing it into the stuff sack. I compared it to my husband's NEMO Forte Endless Promise which uses a 30D polyester shell fabric which is a bit thicker, and the difference is noticeable. I was also disappointed to see feathers in the delivery box and mesh bag, meaning that the sleeping bag was already starting to lose little bits of down. Nothing crazy, but it's not what you want to see when you spend $400 on a sleeping bag and haven't even used it yet. Lastly, the stuff sack feels a bit small for the sleeping bag. It fits in the end, but you have to make sure you're packing it in really tight right from the beginning, otherwise you won't be able to store it. I found this out the first time I tried to pack my sleeping bag in the stuff sack, and ended up having to restart halfway through packing because I realized it wasn't going in. Other than that, I've come to love this bag! I love the warm zip, I was skeptical about it at first, but after using it I found it to be a great addition and it's super for helping to regulate heat. I have the -6°C bag, and slept very comfortably in about 10°C weather by unzipping it. I also really like that there are multiple size options, as I was able to get a bag that suits my measurements really well. Overall, I would say that this is an excellent sleeping bag, there are just some little things that could be improved. P. S. It would be great if Therm-a-rest also made sleeping bag liners for this bag and it's multiple sizes, as there are not many brands that carry liners with arms holes. I was able to find one with arms holes by Sea to Summit, and although it does the job, it's much too long for my sleeping bag."

— Stephanie (4/5)

Q&A