Mt Washington 3 20°F Three-Season Hammock Underquilt

$289.95

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Mt Washington 3 20°F Three-Season Hammock Underquilt

Name: Mt Washington 3 20°F Three-Season Hammock Underquilt
Brand: Jacks R Better
SKU: MW320
Price: 289.95 USD
Availability: InStock
Rating: 4.96 (26 reviews)

$289.95

10.35 oz of 850FP down where 7.6 hits the 20°F rating — 36% optimized fill, standard. It doesn't add loft; it stops the down shifting and holds the rating for years. Dual differential cut, suspension included.

⏳ Made to order — ships in ~2–4 weeks

Handmade in the USA
Free shipping over $249
Satisfaction guaranteed
Easy returns

The Mt Washington 3 is JRB's 20°F three-season hammock underquilt — full length, and filled 36% over what its chambers need to hit 20°F, at no extra charge. Dual Differential Contoured Radial Baffles — the construction we invented — plus the JRB Suspension System and a storage bag, handmade in the USA.

Built for Hammock Campers Who Want to Sleep Warm from Below, Not Just on Top

Sleeping in a hammock introduces a problem ground campers never face: every bit of insulation beneath your body gets compressed flat by your weight, losing its loft and nearly all of its insulating value. A sleeping bag used underneath is simply not doing what it was designed to do. An underquilt solves this by hanging freely below the hammock fabric — it never touches your body, never gets compressed, and the down stays fully lofted all night.

Without an underquilt, no amount of insulation on top of you will keep you warm below 50°F in a hammock. The Mt Washington 3 is the solution for three-season temperatures down to 20°F, full length at 77 inches, head to foot.

How It's Built: Dual Differential Cut — The Construction We Invented

The Mt Washington 3 uses Dual Differential Contoured Radial Baffles — a construction we invented at Jacks R Better and have been sewing underquilts with since 2004. It is the thing that separates a purpose-built underquilt from a top quilt repurposed underneath. The inner shell is cut smaller than the outer shell, so the quilt conforms to the curved underside of a loaded hammock instead of the two shells pulling together at the edges and compressing the down between them. A flat-cut quilt compresses the down exactly where it matters most as it curves around the hammock. The baffles run radially to follow the contour of your body, which is what holds loft height constant from head to foot as the hammock changes shape under you.

Suspension is by adjustable shock-cord loops at each end, included — and you cannot hang it too tight. Because the outer shell is cut larger, it keeps its slack no matter how far you pull the suspension down, so tightening seals the edges against draughts instead of crushing the loft. Ease those same cords off instead and the quilt eases away from the hammock, letting air move across your back — we call it opening the windows, and it is handy on the nights you climb in hot. You also cannot be too warm underneath — the same reason you sleep on the same mattress in July as in January. An underquilt warms only your back; the rest of you stays open to the air, so there is no sealed pocket to trap heat the way a sleeping bag does. Carrying more rating than the night calls for costs you nothing — here is how to pick between 40°, 20° and 0°F. Setup takes under a minute on all gathered-end and bridge hammocks — ENO, Hennessy, Warbonnet, Dutchware Chameleon, and most DIY builds.

Every Mt Washington 3 ships in a storage bag that does not compress the down.

Optimized Fill: 10.35 oz of Down Where 7.6 Would Do

Everyone else calls it overstuff and sells it by the ounce. We call it optimized fill, because a quilt filled only to its base rate fails two ways. The down has slack to move in, so it drifts to one side of a chamber and leaves the other side thin — and a thin chamber is a cold spot. And down loses loft as dirt, body oils and dust work into the plumules, so a quilt with no fill to spare drops below its rating within a season or two.

This quilt's chambers require 7.6 oz of 850FP down to reach 20°F. Every Mt Washington 3 ships with 10.35 oz — 36% over. Not an upgrade, not a dropdown, not priced separately. That extra 2.7 oz is what takes the slack out and supplies the margin — which is why we'll still call this a 20°F quilt in its fifth season.

Here's our arithmetic. Check it against anyone else's.

42″ × 77″, 11 chambers × 2″ baffle walls, lofting to 2.5″ = 6,468 cu in internal volume
6,468 ÷ 850 fill power = 7.6 oz base fill rate — the down this quilt needs to reach 20°F
× 1.36 = 10.35 oz of down actually in the quilt (293.4 g, if you'd rather weigh it)

Those are the three numbers to ask any maker for. Matching this much fill elsewhere runs $27 to $41 on top of the listed price, and it is built to order. Ours is in the price and on the shelf. How the base fill rate is worked out, and how to run this comparison on anyone else's quilt.

Named for the Trail

Mount Washington, at 6,288 feet, is the highest peak in the northeastern United States. The summit weather observatory has tracked temperature swings, icing, and wind events that make the Presidential Range the most exposed section of the entire Appalachian Trail in shoulder seasons. The trail crosses above treeline for miles with no shelter. Spring comes late and fall comes early. What looks like a three-season trip to the White Mountains can turn into something far colder by nightfall.

The Mt Washington 3 is named for that mountain because the principle is the same in a hammock: bottom insulation is not optional once temperatures drop. This underquilt was built for the kind of nights where you're glad you planned for worse than the forecast.

Handmade in the USA by Jacks R Better, sewn in Pennsylvania — making quilts since 2004. In-stock quilts ship the same or next business day. If it's sold out, order anyway — that puts you in the build queue, and we'll sew yours and ship it in about 2–4 weeks. Finished quilts go to the people already in line, so waiting for one to reappear on the shelf usually means waiting longer.

Specs

Weight	19.5 oz (0.55 kg)
Length	77.0 in (1.96 m)
Width	42.0 in (1.07 m)
Temperature rating	20°F (-7°C)
Down fill power	850+
Down weight	10.35 oz
Loft	2.5 in
Shell	1.1 oz Taffeta w/ DWR
Construction	Dual Differential Contoured Radial Baffles
Features	Underquilt – 3 Season
Includes	Zippered storage bag, JRB Suspension System
Made in	Hulmeville, Pennsylvania, USA

Compare all quilts

5 stars: 25 (96%)
4 stars: 1 (4%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 0 (0%)

Recently spent three nights up in the WV mountains with my new Mt. Washington 3 underquilt. Snugged the underquilt up against my hammock as the temps dropped into the 40s and was warm as toast. It was kind of like the underquilt was heated - somewhat blown away. A quality product and an all around good experience with JRB. Speedy shipment and quick response to questions. Five stars for sure!

Great option to save some weight when hiking.

The under quilt has made such a difference in sleeping comfortably in all weather conditions by taking off the under chill. A perfect fit every time. Glad Jacks R Better is around. Thank you.

This was definitely a game changer for my Hennessey Hammock. It was a little finicky to set up the first time, but once I figured it out, I was sold. Super light and packs down small in the included stuff sack. Best addition to my set-up. Absolutely no regrets. I highly recommend it.

Warm, cozy and high quality. Definitely recommend!

The quilt itself is well made and works. I bought it to fit my Hennessy Explorer and found that although it fits, it's quite tight and often slips down off my shoulder.

I recently camped in high winds and temps down to about 14F. I used both the 0F and a 20F underquilt. The first night, I hung the under quilts wrong and got some wind under the hammock so it was a bit cold. Next day, I figured out what I'd done wrong and that night I slept hot! I'm sure I didn't need the double quilt setup and the Washington would have been sufficient. Too bad winter is almost over. Nice quilt, wonderful service. Thank you!

Greetings from Germany. The underquilt is so cool for the hennessy hammock. Everything fits perfectly. The pictures in the description should be redone, because the color is much better in real. Awesome dark olive forest camouflage. Mega cool. If I don't want my ass to sweat at night, because the thing is really warm, then I can adjust it well using the cuffs at both ends. I'm 1.98 m and the length still fits. And it weighs next to nothing. Really a great product. Delivery to Germany was so lala. Let me put it this way, I was happy when the delivery arrived. All in all, I am more than satisfied.

As someone who goes hammock camping trips and outdoor adventures, I was excited to try the Jacks R Better Mt. Washington 3 Hammock Underquilt for. While this underquilt is primarily designed for camping in colder conditions, I wanted to see how it would fare in more relaxed, warmer settings.

First and foremost, the quality of materials used in the Mt. Washington 3 is excellent. The construction feels solid and durable, and the down insulation provides a nice balance of comfort and warmth. Even though I used it during milder weather, I appreciated the extra coziness it added to my hammock setup. It's worth mentioning that this underquilt is designed for colder temperatures, but if you're planning to use it in mild or warm conditions, you will not overheat like you would from top quilt.

The attachment system is simple and effective, allowing for quick setup and adjustments. I found it easy to attach the underquilt to my hammock and make the necessary tweaks for a snug fit. The universal design ensures compatibility with various hammock brands, which is a plus if you have multiple hammocks or plan to share gear with friends.

When not in use, it compresses down into a reasonably small size, making it easy to store and carry.

Overall, the Jacks R Better Mt. Washington 3 Hammock Underquilt is a high-quality product that offers excellent insulation and comfort, at only 19.5 Oz making it a reliable choice for hammock camping.

I purchased 2 JRB quilts in 2016, one for myself, one for my son. Mine gets extensive use AT section hiking and here at home in the White Mtns. The Mt Washington lives up to its rating and then some, having slept on its namesake's southern flank in 15 degrees.
Just stopped by to get another suspension kit for a new hammock, and can swap the quilt between them easier. Thought I'd leave an updated review.
Buy with complete confidence. I treat it right, it treats me right. No signs of wear and tear, at all. Just like new.

Just ordered my second JacksRBetter Mt Washington 20 degree underquilt from one of the owners (Don). First off the friendly customer service and quick shipping we’re phenomenal… A++
Secondly, the build quality and attention to detail on the underquilt were top notch. Lastly, the actual performance of the underquilt in rainy Michigan 30-40F weather was everything I hoped for. I highly recommend this product. Thank you Don and JacksRBetter!
Dave M. 10/20/2022

I purchased the JRB 3 interchangeable quilts, the James River ultra light bridge hammock, stuff sacks, etc. and used them to recently complete a 3-season thru-hike of the AT. The gear all worked great, is well made, and light weight. I had no breakage issues, etc. They even provided me with a light-weight prototype bugnet for my hammock as they did not yet have that product in their standard stock . It also worked flawlessly. Whenever I had a question about usage, etc. their customer service response was amazingly quick, professional, knowledgeable and helpful. I can't say enough good things about JRB products and service!

If you are going to enjoy the winter back country hiking you need the right equipment.
My first UQ I purchased from JRB Was the MT. WASHINGTON 3 back in 2015, worked out better than I expected in temps down in the upper teens.
Then In 2016 I purchased the sierra stealth for warmer weather hiking. It was just what I had been looking for my hammock set up.
Next in 2017 had a chance to get out in -0 temps so I purchased the Old Rag Mtn. UQ and was not disappointed in its performance.
I made the mistake of letting my wife borrow my Mtn Washington 3 on a cold night at a cabin we rented,she wouldn’t give it back until we left.
So in 2017 I purchased her the Hudson River Over Quilt for her winter sleeping pleasure.
My last purchase was the Gray Lock 4 to pair up with the Old Rag Mtn for another winter hike coming up in January in northern Michigan .

Just like with all hiking equipment there are learning curves on how comfortable you want to be.
Jacksrbetter has helped make my backpacking sleeping set up very enjoyable for me.

The customer service alone is worthy of 5+ stars. I am blown away by the help they provided and the quickness they adjusted to my lack of planning. Absolutely an amazing company. I will be testing it out in the TN portion of the Appalachian train and have no doubt it will hold its own. I am super stoked to finally own a JacksRBetter product.

Mt Washington 3 (20F) ~ Elevated Hiker approved.
Maiden voyage was this weekend (Nov. 5-6) on the AT in MD. Low Fri night was 28F and Sat was 31F. Paired with a HammockGear Econ 20F top quilt. I'm a cold sleeper and was warm and comfy so definitely comfort rated. Fabric is very pleasing to the touch and the quilt just hugs you and the construction is flawless which is what you would expect from a cottage company. Not 1 feather popped through the fabric after having it highly compressed in the pack. Simplest suspension I've used yet you can still vent it if needed or snug it up (don't over cinch the ends, just enough to close any gaps). I'm very happy with this quilt! Thanks, JRB!

Mt Washington 2 (20f)
Great service and helpful, had questions and they answered them..
Out of the box/bag- great look and feel, all stitching from what i can see looks good..
Back yard test- first few minutes you could feel the warmth, high 40 w/cool breeze..
Will be using this in the next couple days on a 270+ mile backing trip, light weight and seems to pack down good for my standards..

Last night I field tested my Hudson River 20 degree top quilt and my brand new Mt. Washington 20 degree under quilt. The temperature in my hammock at 0300 hrs this morning was 11 degrees (F) and I was warm with only a balaclava, Smartwool merino 250 base layer, and my 650 fill down puffy jacket. My feet did get cold, but that was due to the lightweight socks I wore. This was a gear test for my upcoming AT thru-hike. JRB quilts performed SUPERBLY and I highly recommend their products. In addition to the two quilts in this review, I have also used their Greylock 3 under quilt (torso length/20 degree) and a Shenandoah top quilt (40 degree).

Mt. Washington underquilt for President! Temps in the 40's and I was roasty -toasty, on the bottom, that is. The Hudson overquilt I ordered should make my comfort complete. The suspension on the underquilt is sooo simple and effective on my Hennessy Hyperlight zip hammock.
I asked my Mother once, "How old was I when you and Dad started me camping in Jungle hammocks (world war 2 surplus hammocks) on the bank of the Delaware river? She replied, "About 2." I'm now 67. Still hanging after all these years!
Thank you for making life simpler and warmer.

I am copying this here from my original Facebook post at Mississippi Hammock Camping group, though it is from back in November, just dawned on me I should also post it here, and in the TQ reviews also:
...................................................................................................................
Here is a report for some hammock stuff that I have had a few years but never really put to the test: a JRB UL Bear Mountain Bridge Hammock(BMBH). I have tested the original model a lot over the years, but this is the UL model and I never actually slept in it over night. Used a discontinued version of the JRB MW3 Under quilt(UQ). This model is a "convertible" which can be used either full length or head to mid thigh length. I have used the winter MW4 on both the original BMBH and WB Blackbird, in really cold weather, works great, but never put the MW3 to the test.
On top I used a JRB Sierra Sniveller with treated down.
The forecast low was 22F, both of these quilts were rated 20-25F, perfect test. I usually sleep in my warm clothing if it is dry, and/or vapor barrier(VB) clothing, but I wanted to test only the quilts, so my only layers were the lightest weight long johns, plus some cotton PJs and T shirt(don't know why I kept the cotton on, I usually don't, cotton is some cold fabric especially if damp!) Also I used my JRB down hood and some VB socks with just my daily wear thin nylon socks over them, no thick wool socks or booties.

Worked great! Oh, I did start out with a light down jacket I was wearing as I set up in the dark under a JRB tarp, and I wore it when I 1st got in, temps in the mid 30s. But after a bit, I could tell I was getting hot enough to sweat, and my head and face were really warm, so I took the jacket off as I planned to anyway. And basically slept anywhere from toasty warm(but with no need to vent) to just warm enough, for the entire night. About 0645, I was awakened by some geese flying over real close, honking away, so I got up (at 25F) and made some coffee. But I stayed warm enough from the back of my head to my heels, and the TQ had no trouble keeping me at least adequately warm on top through out the night. Even without thick wool socks, just the VB socks covered by thin nylon socks, my feet stayed very warm all night. So, I would say that- for this old man who is not quite as hot natured as I used to be, this quilt set's rating is close to dead on. I think I could have gone at least several more degrees without getting too cold to sleep. I also know that with thick layers, and especially with VBs or both, I could easily push this 10-20F lower. So for me works as advertised. Also, the UL BMBH proved very comfy either laying on my back or side legs straight or slight amount of fetal position. No hint of calf ridge or knee extension, as expected. Some minor issues with pillow/neck comfort that I need to work on, need to get the right sized pillow, or no pillow, maybe just a small roll under my neck. All in all, a good combo of hammock, TQ and UQ!

I’ve used my quilt maybe a dozen times and I’ve never felt more comfortable. Coldest has been minus 15 Celsius and I was toasty warm. Thanks Jacks!

Just returned from a hike in trip and tried out my MW3 with 20z overstuff. I am one happy camper! Loaned out my extra top quilt to a kid who was underprepared and I was nervous as my TQ was rated at 35 degrees. The low was 19 and my, now favorite, MW3 kept me warm and toasty all night! Thanks for the recommendation, and thanks for a product that delivered when it mattered!

After fighting my hammock pad for 3 years and freezing, I finally decided to bite the bullet and purchased an underquilt.
I called Jack who quickly answered all my questions regarding overfill, full length quilts vs torso length, etc.
I placed my order for the full length Mt Washington 3 which was received as promised.
The product arrived with suspension and instructions for hanging, although I encourage you to watch the video for install as well.
The quilt is of the quality I have come to expect from JRB, first rate as is their service.
I had the chance to try it out this weekend at the LA Hang during which time the temps got down to about 29 degrees.
Sleeping with the quilt in place under you is an absolute luxury. I was warm and comfortable all night, and not once did I miss fighting to stay on my pad.
This is my second purchase from JRB, my first being a tarp.
They are great folks to by from, selling products that are top shelf quality.
Thanks again Jacks!

I just received my quilt today. I placed the order over the weekend, but JRB was closed until Monday. I called on Monday morning to ask about expedited shipping. I was speaking to one of the Jacks. He told me that they typically arrive in 2 to 3 business days, so I should receive it on time. He also recommended a change to my order based on my needs, which I'm very thankful for now. Later that day, I got a notification that the underquilt was shipped with 2 day expedited shipping, and they didn't even charge me for it. How awesome is that?! These guys clearly care about their customers, and they must be passionate about their products and the sport. I leave for my trip tomorrow and I can't wait to try out this underquilt! It sure looks warm! I'll update my review after I use it.

just got my Washington 3 in the mail I have to work tomorrow but I hung it up anyway it was simple to hang on my hennessy hammock its about 45 degrees outside and so so warm in my hammock Im going to do a few nights in it this weekend it supposed to get below 30 but im not worried. love the stuff sack also.

Outstanding Product. Easy to Install. We recived ours on Feb 15 2013. Like little boys we rushed outside and hung our Hammocks and installed our underquilts. The first night we had temps in the mid 30's we used only a fleece sleeping bag liner. We both stayed warm. Last night tempature was 28 degrees we used our sleeping bags we were exstreamly warm. Had to vent all night Jack was availble to answer all our question prior to buying. Thanks for the help and a great product... Richard

Spent the weekend sleeping in my Hennessey hammock with my new under quilt. It got down to 28 degrees last night. It was so toasty I was coming out of my sleeping bag in the middle of the night. My brother in law was in his and had a similar experience.
Jack was great and did a fantastic job advising me on this product. He did not steer me to the most expensive product but what was best or what we needed. The delivery was also fast and on time. I would recommend this quilt and JRB. Thanks Jack.

Scott