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ENO Vulcan Under Quilt Review

The ENO Synthetic Primaloft Underquilt on a Warbonnet Blackbird - when cooler weather rolls round, you need to add bottom insulation to a hammock to avoid Cold Butt Syndrome
The ENO Synthetic Primaloft Vulcan Under Quilt on a Warbonnet Blackbird – when cooler weather rolls round, you need to add bottom insulation to a hammock to avoid Cold Butt Syndrome

The ENO (Eagles Nest Outfitters) Vulcan Under Quilt is a full length quilt filled with synthetic Primaloft Synergy insulation and has an integrated perimeter suspension system that is compatible with any gathered end hammock. Rated for 35-45 degree weather, it’s priced at $174.95, which is expensive when compared to other synthetic full-length underquilts like the Enlightened Equipment Revolt Apex ($165/65″/30 degrees) and the Arrowhead Equipment New River Underquilt ($155/78″/25 degrees).

The Vulcan is full length quilt as opposed to a partial length one, with an wrap-around elastic suspension system that you secure to the ends of a gathered-end hammock. Like other underquilts, it has a differential cut rather than a rectangular one, that conforms to curve of your body and hammock to improved weight-to-thermal efficiency.

What’s the advantage of a quilt filled with synthetic insulation, rather than goose down? The difference is primarily one of lower cost and larger packed size since a synthetic quilt will be bulkier and less compressible than one insulated with goose or duck down. As a for instance, the ENO Blaze Underquilt filled with 750 fill power duck down is rated for 30 degrees but costs just under $300 or about a 60% premium for a quilt that only weighs 1 ounce less than the Vulcan.

The Vulcan has a wrap-around elastic suspension and hangs from the ends of a gathered end hammock. Unfortunately, ENO does not provide any hanging hardware, so you'll have to source your own.
The Vulcan has a wrap-around elastic suspension and hangs from the ends of a gathered end hammock. Unfortunately, ENO does not provide any hanging hardware, so you’ll have to source your own using mini-biners or Dutchware quilt hangers.


In testing the ENO Vulcan Under Quilt, I repeatedly experienced Cold Butt Syndrome every night I used it in its stated temperature range of 35-45 degrees. Cold Butt Syndrome or “CBS” occurs when your butt gets cold because your underquilt, sleeping pad, or foam pad (whatever you use for cold weather hammock insulation) doesn’t keep you warm. Based on my experience, there’s simply no way that the Vulcan is a 35-45 degree underquilt and I wouldn’t recommend taking it below 50-55 degrees without bringing along a foam pad to augment it.

Specification Errors

After putting the Vulcan through its paces on multiple backpacking trips, I also discovered the specs published by the manufacturer on their website were way off and that the product I’d received was 5 ounces lighter (25 ounces instead of 30 ounces), 9 inches narrower (39 inches instead of 48 inches) and 70 inches long instead of 80 inches).

When I contacted ENO about the discrepancy (I try to give manufacturers a chance to put things right before I publish a bad review), they measured the Vulcans they had in stock and revised the measurements on their website, downsizing the product weight to 25 ounces and changing the online measurements to be 82″ x 45″ from 80″ x 48″, but not the 70″ x 42″ that I reported to them because their in-stock under quilts had different measurements than mine.

But with all of these spec changes, you have to wonder how the Vulcan’s 35-45 degrees temperature rating can remain the same after the weight of the quilt was reduced from 30 ounces to 25 ounces (scratching head). You need to wonder how many people bought quilts where the specs didn’t match up…

Regardless, I recommend giving the ENO Vulcan under quilt a pass. Too cold, not to mention the inaccurate product specs. ENO obviously have some production and quality control issues and I’d advise you to make sure that you verify the weight and measurements of the Vulcan Under Quilt if you buy or have already purchased one, to make sure it matches what you thought you were buying. ENO, to their credit has a two-year warranty, so call them up if your Vulcan doesn’t measure up.

If you want to buy a synthetic underquilt, I’d recommend you check out a cottage manufacturer like Enlightened Equipment or Arrowhead Equipment which both have more stringent quality controls in place because they sew each quilt on a custom basis for individual customers.

Disclosure: ENO (Eagles Nest Outfitters) provided Philip Werner ( with a Vulcan Under Quilt for this review. 

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  1. That would be pretty disappointing for $180. I got CBS last weekend at 35-40 degrees for free! I went with the special offer “No Down Money, Free Shipping” Convective Air-Gap under-quilt.

  2. …and now all gear manufacturers will be checking their specs BEFORE they send you reviewable equipment.

  3. This is the first I’ve heard of an underquilt.
    You know what would be a good idea… someone should take an underquilt and sew it to an overquilt. They could put a zipper down one side for temperature regulation, and add a footbox and a hood to keep your feet and head warm. THAT would be a product I’d buy.

  4. Excellent, straight up review!
    And I appreciate current hammock info very much. Looking to buy light syn underquilt.

    I have an old, specially down overstuffed Peapod I reserve for cold weather. It sure works and differently. Creates a micro climate in there. With thin, boundary layer night clothes like long sleeve and pants silk long johns it’s supremely comfortable — but heavy and bulky. I leave it on hammock, just pull out of pack and hang. Like being in a mini tent–can listen to music and write in there without heavy clothes or oppressive heavy sleeping bag. Not sure I’d do it again with the great new gear these days but it’s paid for!

  5. ENO stuff is crap! If you are serious about hammocking, the cottage gear manufacturers are the way to go. Also, in many cases, their stuff is actually cheaper.

    • They’ve certainly pissed off the hard core hammocking community, which can’t be good. But I don’t know whether I can say that all of their stuff is bad having not tried it. How can you mess up making a single layer gathered hammock?

  6. I did not expect good things when I herd they were putting one on the market .
    Stay away ,to many great vendors like UGQ out there that hits out of the park every time !!!

  7. As a daily reader but infrequent commentator, I wanted to say I appreciate what you do Philip. Too many reviewers seem very close to sales persons with overly glowing reports on not so great stuff, or too picky and only ever choose ultra high end equipment outside of most people’s budgets, and as we all know, much ultralight gear is already fairly expensive…. light on the back and feet often means heavy on the wallet! Proper in the field testing takes time, and there’s little point in testing otherwise. Too many things make it off the drawing board and onto the market only to be failures in real world use. I get teased for reading too many reviews, but I believe in the long run it saves me time, money, and a whole lot of trouble! Nothing like hypothermia to ruin a day or life! Poor design, poor quality, high cost…. we all want better than that. Thanks for setting things straight with this review. I’m sure not only us here but also ENO will have a few thoughts on this one!

  8. This review is complete garbage. While I understand docking the product for cold-butt syndrome, you can’t dock them for inaccurate measurements. That’s not relevant to the product itself. Also, you docked it for not having proper hanging equipment. It doesn’t need anything. It’s designed to work with the SingleNest and works in conjunction with the carabiners on the hammock. It’s an expensive underquilt, but when used PROPERLY with the ENO hammocks, it’s a great product.

    • I respectfully disagree. If I company sells an under quilt that grossly underperforms at its claimed temperature because they’ve shorted the amount of insulation in it, you’re damn right I’m going to ding them on it. BUYER BEWARE

    • Wrong dude. The thing underperformed. (I OWN ONE). and the measurements matter because the smaller quilt actually lets in cold air on the sides. It’s not the end of the world, and it’s still usable, but it certainly could be better.
      Also, it’s 10 degrees off for my comfort level, I thought it was me, but maybe it’s just the quilt. But now I don’t know because a company that can’t be trusted with a simple measurement, can’t be trusted anywhere else either.

  9. I agree with Jack about the review being inaccurate. I’ve owned a Vulcan since last fall and have used it in temps lose to freezing. It performs better than my Yeti UQ, albeit at a heaver weight and larger packed size. Perhaps the reviewer was sent a sample that wasn’t quite up to specs?

    • The manufacturer updated the specs after I pointed out that they were inaccurate. Perhaps they don’t have the level of quality control that they should. Either way, I’d check to make sure you got what you think you’ve bought.

  10. The link to EE quilt isnt the product specified in the reveiw.

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