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 cm³ * 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.