UL Gear: quilts, compared

To quilt or not to quilt?

BPL mummy style UL quilt

First of all, what is a quilt? Imagine you take your sleeping bag and cut out the material with the insulation at the bottom under you. Anyway there is no much loft because insulation is compressed under weight of your body. So in theory you are not effecting the temperature rating of your bag by modifying it that way. However you face another problem – drafts that may come through that hole, especially when you change positions while you sleep. Also almost all quilts come without hoods.

In last decade down quilts became very popular in backpacking world. Both low weight and versatility (quilt may be used as blanket for hotter temperatures) contributed to raising interest in quilts which became a true hype in last years. Nonetheless, in some places/communities quilts are still unknown. A good example is Israel (which is quite weird because Israel climate is best suited for using quilts). Many hikers don’t believe that quilt may provide necessary warmth. Also when you use a quilt you sleep directly on your sleeping pad which is less nice to feel next to skin. And, latest down sleeping bags are not much heavier than quilts with same temperature rating.

When you decide to switch to a quilt, you should clearly understand your goals. For me there are 3 reasons for doing so:

  • Quilt is more versatile. You can use it in a wide range of temperatures because you can always open it flat and pull out your hand/leg if it’s too warm.
  • Quilt is still a little bit lighter than sleeping bag with same temp specs.
  • Quilt is something new, so why not try it? Maybe it will be far more comfortable for me than sleeping bag?

I don’t believe I would use quilt in true winter (not that we have in Israel). Haven’t tried it though, but if you get some chilling drafts in winter it’s no fun.

For first quilt I’d suggest to get a 20°F – rated one because it is still warm enough for shoulder seasons and cool enough for summer nights (depends where you hike of course). There are plenty of manufacturers that make awesome quilts, the problem is what to choose.

Choosing right quilt is not an easy task. Quilt specs may easily confuse: manufacturers advertise many specs like temperature ratings, baffle height, loft, down fill power, overfill and other specs. There are also different features like closure system, draft collar, neck cinch method, pad attachment system and others. For a newcomer into quilts it is hard to understand all these specifications and decide what to buy.

This review includes explanations of different quilt aspects and comparison of popular quilts available on market today (as of 2014).  Let’s start with overview of quilts in this review:

Option

Manufacturer

Model

custom
orders

temp.
rating

price
($)

weight
(gram)

1

zpacks

MED REG

yes

20

390

473

2

nunatak

Arc Alpinist MED

yes

20

469

567

3

enlightened equipment

Revelation Pro reg/reg

yes

20

500

516

4

enlightened equipment

Revelation
reg/reg

yes

20

310

561

5

katabatic  gear

Alsek Regular

no

22

490

624

6

katabatic  gear

Alsek Regular

no

22

480

595

7

Jacks’R’Better

Sierra Sniveller REG + 2 oz overfill (*)

yes

20

285

680

8

Jacks’R’Better

Hudson River REG + 2 oz overfill (*)

yes

20

265

610

9

WildernessLogics

Top Quilt Regular – 2 oz of down (**)

yes

20

225

510

10

WarbonnetOutdoors

Mamba Topquilt

no

20

255

539

*) Jack’R’Better’s quilts are rated to 25-27 °F, so in order to push it to 20 °F I added 2 ounces of down. This affected fill weight, total weight and price of course
**) WildernessLogics Top Quilt Regular is rated to 15 °F, hence I removed 2 ounces to accommodate same 20 °F temperature rating. Hence differences in fill weight and total weight.

Many hikers who decide which quilt to choose think that these basic specs are sufficient for decision making, the truth is that these specs tell you nothing about how quilt is warm. Things are a bit complicated when it comes to comparing different quilts from different manufacturers. Hereby I will explain in more detail what data is important to know when choosing quilt.

Fill/overfill/fill weight

One of most important specs is how much down is in your quilt. Manufacturers specify also percentage of overfill related to their “standard” fill weight. This doesn’t contribute any useful information, so just ignore that “overfill”. What does make sense is total down fill weight. But, this still doesn’t give you all the information to be able to compare different quilts. There are two problems with “fill weight” metric:

  1. You don’t really know how much loft the down will provide when it is distributed within quilt. Say you have two quilts with same fill weight but different area. The one with smaller area will have “thicker” layer of insulation (down) and hence will be warmer. So you need to calculate quilt area in order to compare “down warmth” of quilts.
  2. The quality of down (or Fill Power) used in quilts differs from model to model. The higher the fill power the more air an ounce of the down can trap, and thus the more insulating ability an ounce of the down will have. So two quilts with same fill weight but different down fill powers will perform differently: quilt with higher fill power will be warmer. Hence you need to normalize down fill power.

Down Fill Power

Down of different quality (the weight is the same)

As I mentioned above, Down Fill Power characterizes how much insulation one ounce of down will provide. Without too much drilling down to all the complexities of down fill power measurement, I’ll note that it’s the volume of a bit compressed one ounce of down (further reading is available here: wikipedia). Down Fill Power ranges from 300 in³/oz to 900 in³/oz. To understand these numbers let’s compare two down quilts with down fill powers of 700 and 900 in³/oz. In first quilt each ounce of down will take volume of 700 in³, in second quilt each ounce of down will take volume of 900 in³, so to accommodate same temperature rating (same loft, insulation level) you will need to stuff less 900 power down into second quilt and hence it will be lighter. This is because 900 FP down takes more volume than 700 FP down. If you’re comparing quilts with different FPs, you need to normalize them. Assume that in first quilt (with 700 FP down) we have 15 ounces of down and 12 ounces in second quilt (900 FP). Normalized fill weight:

Quilt A: 15 * (700/900) = 11.67 oz

Quilt B: 12 * (900/900) = 12 oz

Even having 3 more ounces of down (100g more heavier quilt), quilt A is not as warm as it’s ultralight counterpart. Of course if we assume all other specs are same.

With time down looses its loft. The higher initial fill power the quicker loft loss. To compensate future loss of loft, an overfill of one-two ounces is advised. It is also important to understand that quilt’s physical size (baffle height) limit loft. There is a point when stuffing additional down into quilt has no effect on loft and hence warmth; but just adds weight. In this case if you need warmer quilt, just go for higher baffles (higher temperature rating quilt).

Water resistant down

Since down may lose its loft due to moisture, recently (2012) a new method was introduced to treat feathers so that they’ll have hydrophobic “layer”. This allows down to resist moisture. Unfortunately there are still not many reports of how this really helps against humid conditions and whether this hydrophobic ability retains for long. However, during down treatment its original loft retains and practically no weight added, so at least there is no harm caused to the insulation. Of course water resistant down costs more, normally you add $100 for quilt stuffed with treated down. The bottom line: if you can afford buying quilt stuffed with water resistant down, go for it.

Quilt size and area

When looking at quilt size it is hard to imagine whether it is tight fit or loose fit. If you turn  at night a lot, you should consider wider quilt to relief drafts. Best method to find out whether quilt of given size is good for you, is to take a bed sheet and change its shape to the quilt’s shape (safety pins). After that cover yourself with the improvised quilt. Also try to change positions under it.

For this review I’ve calculated  quilt area by approximating its shape with two adjacent trapezoids. In most cases manufacturer provide three girths: at shoulders, at hips and foot. Most quilts fit this model quite well, so error is not big. Calculation of quilt area is quite simple.

JRB flat opened quilt

Since trapezoid area is

,

where: a and b are two bases and h is height of trapezoid; the area of quilt could be found by:

,

where w1 – girth at shoulders, w2 – girth at hips and w3 – girth at foot, h – is quilt length. I assume that each trapezoid has height of half length of the quilt.

In the following table I list all the insulation related specs with calculated normalized fill weight, area and fill weight – to – area ratio, which reflects quilt warmth.

Opt

Manufacturer

model

temp.
rating

fill
weight (gram)

fill
power

Normalized
f.w. (gram)

hydrophobic
down

girth
(cm)

length
(cm)

area
(cm2)

fillweight/area
ratio (mg/cm2)

shoulders

hip

foot

1

zpacks

MED REG

20

312

900

312

available

142

142

76

175

21963

40.98

2

nunatak

Arc Alpinist MED

20

312

800

277.33

no

140

114

96

178

20648

38.74

3

enlightened equipment

Revelation Pro reg/reg

20

347

900

347

yes

137

137

102

183

23470

38.35

4

enlightened equipment

Revelation reg/reg

20

391

800

347.56

no

137

137

102

183

23470

34.09

5

katabatic  gear

Alsek Regular

22

380

850

358.89

yes

132

107

96

183

20222

42.03

6

katabatic  gear

Alsek Regular

22

352

900

352

no

132

107

96

183

20222

44.51

7

Jacks’R’Better

Sierra Sniveller REG +
2 oz overfill

20

374

800

332.44

yes

132

132

107

198

24899

32.13

8

Jacks’R’Better

Hudson River REG + 2
oz overfill

20

374

800

332.44

yes

122

122

122

198

24156

33.12

9

WildernessLogics

Top Quilt Regular

20

340

850

321.11

no

122

122

122

183

22326

38.07

10

WarbonnetOutdoors

Mamba Topquilt

20

298

850

281.44

no

122

122

122

178

21716

39.14

Baffles

Baffle

Like regular sleeping bag, quilt is made of two pieces of synthetic fabric: liner (your body touches it) and shells (outermost layer); between these fabrics comes insulation. To keep insulation uniformly distributed within quilt (eliminate down shifts in quilt), its inner space is divided into compartments with baffles (“walls”). Each compartment is stuffed with its own portion of down. Baffle and compartments geometry is something you should consider when choosing quilt because it affects quilt performance.

Baffle spacing. With time down loses its loft and frees up space in the compartment. This will eventually lead to development of cold spots in quilt. In larger compartments this effect is more likely to occur because more free space is available for down shifts. On opposite, smaller compartments contribute to even down distribution even when it loses loft.

Baffle spacing: (a) – normal spacing with full loft. (b) – same baffle spacing after loft loss, (c) – large baffle spacing after loss of loft, note the cold spot.

However, in quilts with larger baffle spacing there are less compartments, less material is used for baffles and hence the quilt becomes a bit lighter (difference of less than an ounce).

Baffle height. This reflects compartment’s potential loft. If compartment is fully filled, its loft is equal to baffle height (maybe a bit higher since in the middle it may bow out causing more loft). In warmer quilts (for colder temperatures) baffles are higher than in colder quilts. Also, with time down may loose its loft and you might want to add more down or refill in order to gain more loft and hence more insulation (warmer quilt). Baffle height is maximum loft you can get.

Baffle shape (horizontal/vertical/karo/square). Horizontal baffles are those that go from side to side of the quilt (left to right). One thing to consider with this type of baffles is that down may fall to the sides within compartment creating cold spot on top of you when you sleep under it. With time this effect may become worse, especially if you are a side sleeper. Vertical baffles, allow you to shift down to bottom part of quilt in order to provide there better insulation and hence more warmth. Vertical baffles are less prone to unwanted down shifts. It is a preferable choice in my opinion. Karo baffles are squares with corners “cut out”. Karo baffles are good compromise between possibility of moving down around when you need it and prevent unwanted down shifts. Square baffles do not allow any down shift. There is however possibility of differential fill: each compartment may have different amount of down.

Quilt liner, shells and baffle fabrics. Generally, if manufacturer allows to choose fabrics for inner and outer shells (like in Enlightened Equipment), you might want soft inner fabrics that will be nice next to skin and more durable DWR fabrics for outer shells. However, not many (or none) of quilt manufacturers allow to choose fabrics for baffles. The options are: Cuben Fiber and No-See-Um netting. There is a negligible difference in weight.

Quilt volume & down saturation. To calculate volume of quilt we may use previously calculated area and multiply it by baffle height. Quilt volume itself is not that interesting, but it can reveal helpful information. Let’s calculate how much volume could occupy down (normalized) in ZPacks quilt that appear in this overview. 11 ounces of 900 FP down will occupy (if pressured as described on Wikipedia link above) 11*900 cubic inches or 11*900*2.543 cm3 = 162232 cm3. Now, if we multiply quilt’s area (we calculated above) by baffle height, we actually get the quilt potential volume: 21962.5 cm* 5.7 cm = 125186.25. First of all we conclude that the down volume is larger than quilt’s potential volume, this guarantees maximum loft. Now, let’s find ratio of these volumes (what is the portion of down volume in quilt volume): 162232/125186.25 ≅1.3. I called this metric down saturation. Higher values of down saturation mean that there is too much down, further overfilling is worthless and only adds weight with no contribution to warmth. Lower values indicate that the quilt might lose its loft faster and overfilling might help to keep its loft.

In the following table I calculated all baffle-related metrics:

Opt

Model

Normalized
fill weight (gram)

area
(cm2)

baffle
type

baffle
height (cm)

baffle
spacing (cm)

outer
shell fabrics

inner
shell fabrics

baffle
fabrics

qulit
volume

down
volume

Down
saturation

1

zpacks MED REG

312

21962

horizontal

5.7

12.7

.75
oz/sqyd (25.4 g/m2) Pertex GL Ripstop Nylon with durable water
repellant.

.75
oz/sqyd (25.4 g/m2) Pertex GL Ripstop Nylon with durable water
repellant.

.34
oz/sqyd Cuben Fiber

125186

162313

1.296

2

nunatak Arc Alpinist
MED

277.33

20648

horizontal

6.35

12.7

0.8 oz Pertex Quantum

0.8 oz Pertex Quantum

?

131114

144276

1.100

3

enlightened equipment
Revelation Pro reg/reg

347

23470

vertical, horizontal
at footbox

6.35

13.97

Phantom
10D

Phantom
10D

No-See-Um Netting

149033

180521

1.211

4

enlightened equipment
Revelation reg/reg

347.56

23470

vertical, horizontal
at footbox

6.35

13.97

Phantom
10D

Phantom
10D

No-See-Um Netting

149033

180812

1.213

5

katabatic gear Alsek Regular

358.89

20221

horizontal

7

13.3

Pertex Quantum Ripstop
.85oz/yd

Pertex
Quantum Taffeta 1.0oz/yd

No-See-Um Netting

141550

186707

1.319

6

katabatic gear Alsek Regular

352

20221

horizontal

7

13.3

Pertex Quantum Ripstop
.85oz/yd

Pertex
Quantum Taffeta 1.0oz/yd

No-See-Um Netting

141550

183122

1.293

7

Jacks’R’Better Sierra
Sniveller REG + 2 oz overfill

332.44

24898

horizontal

5.08

14.2

1.1
oz., 30 denier, ripstop nylon

1.1
oz., 30 denier, ripstop nylon

No-See-Um Netting

126484

172946

1.367

8

Jacks’R’Better Hudson
River REG + 2 oz overfill

332.44

24156

horizontal

5.08

14.2

1.1
oz., 30 denier, ripstop nylon

1.1
oz., 30 denier, ripstop nylon

No-See-Um Netting

122712

172946

1.409

9

WildernessLogics Top
Quilt Regular

321.11

22326

horizontal

5.08

12.7

1.1 oz. ripstop nylon

1.1 oz. ripstop nylon

No-See-Um Netting

113416

167052

1.473

10

WarbonnetOutdoors
Mamba Topquilt

281.44

21716

horizontal

5.08

12.7

30D Nylon, DWR

30D Nylon, DWR

1.0 oz noseeum mesh

110317

146414

1.327

Features

Most quilts are not just blankets, but are feature-rich pieces of gear. Some features keep you warmer like draft tubes, draft collars, quilt closure systems, zip closures or sewed foot boxes. Others are just for convenience like pad attachment systems. It is important  to know features of a quilt and whether they meet your requirements or not.

Draft tube. Those quilts with closure system (ZPacks for example may be fully closed with zipper) may have cold spot right at the closure (zip) because there is no insulation at all. Specifically zipper of ZPacks bag/quilt designed to be laid on bottom, under your body, so you don’t need insulation there. In quilts with zipper closures a draft tube maybe placed over the zip. A draft tube is basically a baffled tube filled with same insulation as quilt. Also, if footbox has zipper closure, draft tube will prevent unwanted heat escape.

Draft collar. Most quilts have cinching cord on top to close the quilt around your neck. A collar maybe sewed to the edge of the quilt opening to provide extra warmth at neck, which is very sensitive area. Draft collar like draft tube is made of same materials as quilt itself.

Quilt closure system. When I say closure system I don’t mean something that completely closes the quilt and makes a sleeping bag (like ZPacks). Instead, it is something that keeps quilt closed around you to eliminate drafts. Those who use quilts without closure system might  simply tuck the quilt edges under their body to eliminate drafts. Looks like these people don’t toss and turn a lot while they sleep. Some quilts provide some way to keep the quilt around you all the night (Katabatic and Enlightened Equipment for example use cords and locks/clips).

Shaped footbox. To form footbox, bottom part of quilt (the end closer to feet) should be closed either with zipper, cords or velcro. If foot box is not designed to be in a “foot shape”, your thumbs might cause pressure points and tension creating cold spots. This effect is more likely to occur if you have bigger feet.

Pad attachment system. Imagine yourself changing positions under quilt. When you sleep under quilt you sleep right on your sleeping pad, and hence when you turn it is hard to keep the quilt in place. Pad attachment system can greatly improve your sleeping. You can however use the technique you apply every night at home when you sleep under blanket, but the problem here is that quilt is generally smaller and each time when you create opening between quilt and pad you get cool draft. Pad attachment comes to solve this issue by keeping quilt in-place for the whole night.

Option

Manufacturer/model

footbox

draft
tube

draft
collar

pad
attachment

opens
fully

closure
system

neck
cinch  cord

1

zpacks MED REG

sewn, not shaped

opt. 20 gram $20

no

no

no (custom mod
available)

3/4 length zipper

elastic cord

2

nunatak Arc Alpinist
MED

sewn, shaped

no

no

2 straps go underneath
the pad

yes

buckles + straps under
body

cord

3

enlightened equipment
Revelation Pro reg/reg

cinching + zipper

no

no

straps underneath the
pad + bucles on sides of quilt

yes

elastic straps +
buckles on sides of quilt

drawcord

4

enlightened equipment
Revelation reg/reg

cinching + zipper

no

no

straps underneath the
pad + bucles on sides of quilt

yes

elastic straps +
buckles on sides of quilt

drawcord

5

katabatic  gear Alsek Regular

sewn , shaped

no

YES!

cord coming under pad
+ adjustable clip

no

elastic binding

cord

6

katabatic  gear Alsek Regular

sewn , shaped

no

YES!

cord coming under pad
+ adjustable clip

no

elastic binding

cord

7

Jacks’R’Better Sierra
Sniveller REG + 2 oz overfill

draw cord with
cordlocks to close the bottom and 21” of omni-tape (Velcro) on each
side of the foot end that seals together to form the foot box. Sewn in
footbox available

no

no

6 lacing tabs

yes

no closure system

yes

8

Jacks’R’Better Hudson
River REG + 2 oz overfill

draw cord with
cordlocks to close the bottom and 21” of omni-tape (Velcro) on each
side of the foot end that seals together to form the foot box. Sewn in
footbox available

no

no

6 lacing tabs

yes

no closure system

yes

9

WildernessLogics Top
Quilt Regular

sewn or a drawstring
footbox with snaps

no

no

no

no

SHOCK CORD TO TIGHTEN
UP AROUND SHOULDERS OPTION + snap @ head

shock cord

10

WarbonnetOutdoors
Mamba Topquilt

sewn, comes up to just
below the knees

N/A

no

no

no

a tie-off point 6”
higher up to extend the footbox farther if desired

elastic drawcord

To conclude this overview, there is no best quilt. However I believe this brief overview shed some light on the important aspects to consider  when choosing quilt. I hope you find it helpful.

Advertisements

9 Responses to UL Gear: quilts, compared

  1. Stick says:

    Haven’t read through it all but I noticed you have the EE Revelation Pro marked at $500 in your first chart. That made me wonder since EE is usually one of the best priced companies, so I checked (via your link) and it should be listed at $350.

    ~Stick~

    • thehikingdad says:

      You are totally right. I should update this review. At the time of posting these were the prices Tim Marshal published. I will update and recalculate relevant fields. Thanks for pointing it out!

  2. Really great article – love detailed articles like this! I shared it on my facebook page: https://www.facebook.com/HikeLighter/posts/285783458212151

  3. Derek says:

    Great details! Thanks for writing.

  4. Hiking Mom says:

    Came here via the John Abela link. Nice to see another site dedicated to hiking with kids. There aren’t many outside of the USA.
    At this very moment, I’m waiting for my two Cumulus (http://cumulus.pl) comforters to arrive: flat quilts that you can configure the way you want. They also have footboxed quilts. I’m quite happy that you can get quilts outside America too now!

  5. Theo says:

    Nice work you did there! Especially for the data acquisition, those charts are really handy!
    One personal preference: I found the “normalized fill-weight” idea a little strange. It’s a little hard to get an intuitive feel for a quantity measured in mg/cm^2. Why not just calculate ‘potential height’ which is Volume/area=fillpower*fillweight/area? That would also allow a direct comparison with the actual baffle height. But your version is accurate aswell, just harder to grasp imho.

    My main point is actually a different one. I tried to check some of your calculations but I get different results for the “norm. fillweight/area”-calculations. Take the zpacks for example. 312g/21963cm^2=14.2mg/cm^2. Or did I make a mistake?

    Thanks again for the good work!

  6. Ed B says:

    I think perhaps your numbers for quilt area are not taking foot boxes into account. The length of the quilts you have is the user height, not the shape of the quilt trapezoid before it is sewn into a footbox. For instance, the current EE Revelation 6’6 quilt is 84 inches long, but the Enigma is only 78 inches long in a finished height, or exactly 6’6. However, they actually use the same 84in footprint. This is why they share the same amount of down, with only .5oz difference in total weight, for the zipper and draw cord of the Revelation. By the same token, the actual length of the Katabatic and Zpacks quilts are longer than stated here, around 6in longer. I’m also not sure whether you are correctly calculating your fill weight to area ratio in the first table. There, the EE Revelation 900 fill quilt (now called the Revelation Elite) should have a higher fill to area ratio than the Zpacks quilt, according to the grams of fill and areas you have written. Perhaps I am missing something here? Finally, shell weight to fill weight ratio is a good way to quantify a warmth/weight ratio, another important factor you might consider in your analysis. Cheers and thanks for the thorough write-up.

  7. mediumsteve says:

    I own an embarrassing number of topquilts. Actually I currently have quilts from each of the makers you list, with the exception of Katabatic. And more.

    But I’d say that hammockgear.com makes the very quilts, from design to manufacture to delivery. And they come in at a lower price than those you list.

    The Zpacks cuben-bottomed underquilt I got is also a favorite and is no longer made. But it deserves mention because its wind-resistance allows me to comfortably use a diamond-shaped tarp.

  8. mojubee says:

    So… your fav?
    Katabatic or Enlightened??

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s