Why am I cold with an underquilt?

[Jenny A]

I am new to hammock camping and spent my first night outside last night, 41 degrees with a 20 degree underquilt, no wind, but I was chilly.  Had a 30 degree quilt on top, but I could definitely feel cold on my underside.  I snugged the underquilt tight on both ends of the hammock, which helped a little, but at 7 a.m. I dragged into the house to warm up.  I’d like to get this dialed before taking the system to the high country.

I am using a Western Mountaineering SlingLite 20 degree underquilt.  It is 3/4 length and tapered at both ends.  Coverage seems fine, but I’m just wondering if I am missing some critical thing.  BTW, I did sleep really well, and my back wasn’t stiff in the morning, a big WIN!

[Matthew / BPL]

I’m not a level 19 hangwizard but I’m under the impression that the two most likely causes would be either there is an air leak or you are over-compressing the UQ. I’d recommend having someone help you out while you are laying in a sleeping position to see if either of these conditions might be happening. It’s hard to feel around for it yourself without moving out of the sleeping position. You want it to fit snugly but not too tight.

[Kevin Babione]

Matt’s right, except that I don’t think it’s possible to over-compress the UQ.  Even stretched fully it should be able loft to its maximum amount because there’s nothing to compress it.  A couple of questions:

• Can you remember where you were feeling the cold?  CBS (Cold Butt Syndrome) is the most common problem hammocking, but with a 3/4 UQ it might have been either your head or your feet that got cold.  If you sleep cold you might need either a pillow under your head for insulation or a sit pad under your feet.
• If you can lay in your hammock with someone who can run their hands between the UQ and the hammock it might show where you have gaps.  It should fit snugly throughout the length of the UQ.
• Were you sleeping in the “banana” position  (body parallel to the hammock lines) or diagonally across the hammock to flatten it out?  Sometimes I’ve found that laying diagonally means I’m “off” the quilt more because it’s a rectangle that parallels the hammock.
• I’ll give you the benefit of the doubt, but your UQ was mounted underneath your hammock, wasn’t it?  One of my buddies, the first time he borrowed one of my UQ’s for his hammock, put it inside his hammock rather than under it!  It was under him (which is what he thought it was for), but it belongs under the hammock.  I happily caught it before we went to sleep by asking:  “Where’s the under quilt?”  When he told me where it was we corrected his issue.  He sheepishly told me that he was wondering why there were clips attached to mini-bungee lines…

[Jenny A]

Matthew and Kevin, thanks for the suggestions.

It was definitely my hips and butt that were cold, head and feet were fine.  I’m going to try loosening the quilt a little to create a bit more air space in case I’m actually compressing the underquilt (and it is hanging underneath the hammock – no one is born knowing everything, right?).  Might have my hubby check for fit while I’m lying in the thing, that is hard to do by oneself.  I am lying on a diagonal, so should be plenty of insulation in the midsection of the quilt.  Similar temperatures forecast for tonight, so should be a good test.  Boy, it’s nice to be sleeping outside again, even if it isn’t in the mountains!

If creating slightly more air space isn’t the answer, then I’ll go the opposite route and snug things up.  Gotta be one of those 2 things.

[Kevin Babione]

Good – I’m glad to hear it.  Nice that you can set up and practice in your back yard.  You should be good – I’ve found the UQ to be more important than the top quilt in terms of keeping warm.  And thanks for not being offended by my comments…

Let us know how it goes.  My first night in a hammock I used a Z-Rest pad as my insulation.  I was comfortable but knew that the pad wasn’t the answer for me.  I bought my first UQ and never went back.

[Matthew / BPL]

Is this drawstring snug? I have a similar adjustment on my HG UQ and find that it makes a difference in overall warmth.

[Matt Dirksen]

In the green remodeling world, us architects and building professionals use a very simple analogy about the importance of removing air gaps:

One square inch of air leakage in your home’s wall is equivalent to eight square feet of ZERO insulation.

Regarding hammock camping, I suspect a very small air gap in your system could severely impact it’s ability to insulate you. Even worse if you have air gaps at opposing ends, thus creating convection opportunity. And moving around at night could make it even worse.

As Matthew mentioned, closing up the those drawstrings at the head and foot could prove to be very helpful, I suspect.

But I admit, I don’t hang anymore, so I’m only speculating.

[Jenny A]

Matthew and Matt;  things were much better last night (low temp 43 degrees, a tad warmer than two nights ago).  I cinched up the drawstrings on both ends as you suggested, Matthew, and that seemed to do the trick.  Matt, comments on creating air flow via two small openings makes total sense.  I’m thinking that was the issue, solved by tensioning the ends.  I’m also trying to ensure that I’m not compressing the down underneath my hiney, in fact I loosened the tension just a tad to create a little more space there.

There is a ton of info on all things hammocking out there, and I appreciate your helpful suggestions.  It’s fun to be tweaking the system to be ready for the backpacking season!  I think the 20 degree underquilt (maybe 20….) paired with the 30 degree quilt are going to be about perfect.

[Chris Bell]

I searched for photos of that underquilt and it appears the shock cord runs through the entire hemmed edge, length, of the quilt.  If it does some times the quilt will sag in the middle.  The shock cord will lift but not lengthen the quilt.  It can “accordian” become shorter and scrunch up leaving a gap in the middle area.  That design may have a method to correct for that but I am not familiar with the quilt.  Just something to look at.

[Matthew / BPL]

Jenny, I missed your follow up but I’m glad it’s working better now!

[Jenny A]

Chris, you are correct about the shock cord running the length of the under quilt on both sides.  There are two plastic clips on each side of the under quilt designed to hook onto the edge of the hammock and prevent the sagging that you describe.  Unfortunately, they do not seem to stay attached.  That might be because this particular hammock is a double; I’ll have to try the under quilt with the new single hammock  that just arrived in the mail….

The backyard experiment was a success!  I was comfortable down to temps of 36 degrees, though I don’t think I’d push this particular system much below that.  My tarp (a Sea to Summit) kept some light rain off, although the mini Groundhog stakes pulled out – I might swap out for regular Groundhogs.  It was so comfortable that I am pondering how to rearrange stuff in one of the kids’ old rooms to hang a hammock for sleeping in the house.

[J David Sullivan]

I have both a Warbonnet and an Enlightened Equipment underquilt, which I use during the winter, depending on what I grab first. Each has kept me warm down the low 20ºs. However, because I don’t like to wake up cool in the night and fiddle with cold spots, I have always slept on a Z-lite pad underneath my back and butt. During the winter I use both the pad and the UQ. During the spring and fall I use just the pad. During July/August I use a sitpad under my butt (I’m old and don’t have much natural padding there). With just the full pad, I was warm at 44º last weekend. I also have a Nemo Switchback pad which I’ve used a couple of times. It is warm for me. When I just used an UQ I never could keep sufficiently warm at 4AM, so I solved it with the pad; besides, the pad is very useful for mid-day naps along a trail.

[Christopher W]

One thing that I did with my Jacks R Better underquilt that has the same cord through design is to use a prusik knot to keep the quilt tight. I don’t know if this will help with your quilt but made a tremendous defference with mine. https://www.youtube.com/watch?v=7uKRt3PaUgs

[DAN-Y/FANCEE FEEST]

These 2 videos might help.

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