Mt Washington 3 (20F)

(12 customer reviews)


Conservatively rated to 20° F(-7° C) the Mt Washington 3 underquilt features a dual differential cut, body contouring design with constant height radial baffles.

Mt. Washington 3 Under Quilt
Length: 77 inches (1.8 m)
Width: 42 inches (1.07 m)
Weight: 21  ounces (0.59 kg)

Over-stuff: 25% over-stuff included!

Compression Sack: For 20 degree quilts we recommend the large size compression sack.



Using a hammock underquilt means no more wrestling with pads inside the hammock. No more waking up cold in the middle of the night. The Mt. Washington hammock underquilt works on any hammock – including all gathered end hammocks and bridge hammocks. It attaches to a hammock in under a minute with the included JRB Suspension System.

Over-stuff: 25% over-stuff included!

All Jacks ‘R’ Better quilts are over stuffed by at least 25%. We do not recommend additional over stuffing. If you think you need additional over-stuff consider purchasing the next warmer quilt model.

Compression Sack: A lot of folks no longer use compressions sacks and instead keep their quilts dry inside a lawn contractor bag or trash compactor liner.  We do not want anyone to have to pay for something they do not want so now we offer them separately. For 20 degree quilts we recommend the large size compression sack.

The Mount Washington 3 hammock underquilt works on ENO Hammocks, Hennessy Hammocks, Warbonnet Hammocks, Dutchware Chameleon, as well as most other brands and DIY hammocks.

Mt. Washington, at 6288 feet, is the home of the world’s worst weather: bitter cold, heavy fog, deep snow, and incredible wind … occasionally a beautiful day. To tackle the winter’s worst conditions, Jacks ‘R’ Better has designed a unique hammock underquilt with a dual differential cut, body contoured design and constant height radial baffles to achieve a 20 degree capability. These are the most capable and warmest commercially available hammock underquilts.


Just Jeff’s Hiking Page
Backpacker Gear Test
Backpacker Magazine

Activ-dri down™ – Activ-dri™ is a hydrophobic down treatment that keeps the down drier, while having no adverse effects on loft, fill power, or warmth retention. Activ-dri down is still down insulation and should be protected from direct exposure to moisture. All types of insulation, whether down or synthetic, will degrade in insulation capability if wetted.

12 reviews for Mt Washington 3 (20F)

  1. Scott

    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.


  2. Richard Cunningham

    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

  3. Caleb Yagow (verified owner)

    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.

  4. Jake

    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.

  5. Kenny Vairin (verified owner)

    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!

  6. Dennis Gay

    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!

  7. Sherri

    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!

  8. Bill Kline

    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!

  9. Patricia J Gardner (verified owner)

    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.

  10. John Petrie II (verified owner)

    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).

  11. Dennis (verified owner)

    I finally got my first down product last fall and got to use it last weekend at AZ spring hang.
    It fits my diy bridge hammock perfectly and I am really impressed and satisfied

  12. Chip Hungerford

    I have a Mt. Washington 3 full length under quilt and a Sierra Sniveler top quilt, both 20 degree rated. I have only been out to 30 degrees and as high as mid fifties at night and I love both products. I use them with a Dutchware Chameleon and there is plenty of coverage on the bottom extending from beyond my head to my feet and the width of the top quilt is more than enough to to wrap around my shoulders when on my back or side. During the 50 degree night I loosened up the drawstring at the top and bottom of the under quilt to vent it a bit and I was nice and warm but not over heated at all. The foot box on the top quilt is secure with the Velcro and draw string but easily ventable or you can pull a leg out if needed. Overall quality of craftsmanship seems great, I would recommend this combo to anyone looking for a good 3 season quilt set . Also the quilt was at my door 3 days after I placed the order.Keep up the great work Jacks R Better

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