Backpacking Sleeping Bags and Quilts Under 2 lbs: Rating vs Weight

Two pounds is 907 g, and every product in this comparison is under it, from 510 g, which is 18.0 oz, to 822 g, which is 29.0 oz. That is a spread of only 312 g, about 11 oz, across claimed ratings from 30F down to 10F and list prices from $239.95 to $600.00. The weight range is narrow. What differs enormously is what you gave up to land inside it: down quality, fill quantity, shell fabric, shape, whether the rating was tested by anybody, and how much you paid.

A sleeping bag does not make heat, it slows the loss of yours. Insulation underneath you is compressed flat by your body weight and contributes close to nothing. That job belongs entirely to the pad. Which means the number printed on the bag is at best half of the answer to whether you will be warm, and a warm bag on a cold pad fails just as reliably as a thin bag on a good one.

This is a comparison of published specifications: manufacturer listed weight, listed shape, listed fill power, manufacturer temperature rating, and manufacturer list price. We have not tested, measured, or field-trialled any of these. No loft measurements, no thermal manikin, no cold-night trials, no scale of our own. What follows is arithmetic and cross-referencing on numbers the manufacturers themselves publish, plus a hard look at how few of those numbers are actually verifiable.

I sorted by listed weight, 510 g up to 822 g. Anything outside that set is not published in what I am working from and I will not invent it: baffle construction, shell denier, shoulder and hip girth, draft collar details, and fill weight in grams are all absent. Fill weight is the one that hurts, because fill power on its own tells you loft per ounce of down but says nothing about how many ounces are in there.

Fill power is the volume in cubic inches that one ounce of down expands to under a standard load. 850 fill lofts more per ounce than 800 fill. That is a measure of the quality of the down, not of the warmth of the finished product. Warmth comes from total loft, which is fill power multiplied by how much down is in the thing. A high fill power number tells you the maker used good down. It does not tell you they used much of it.

The proof is inside this comparison. The Feathered Friends Hummingbird UL 20 is 950 fill power at a listed 624 g, 22.0 oz, rated by the manufacturer to 20F. Whatever explains that sits in fill weight, shell fabric and cut, and none of those are published here.

Run it the other direction and the trade is just as visible. The Hammock Gear Economy Burrow 20 is 800 fill power at 709 g, 25.0 oz, rated by the manufacturer to 20F, list price $239.95. Lower grade down, more grams of it, the same claimed rating, and the lowest list price in this comparison. That is the entire fill power economy in a single product: you are buying weight savings, not warmth.

With a single exception, every temperature figure in this guide is a manufacturer claim and should be read as one. We have not verified the test standard behind any of them, ISO 23537 or the older EN 13537. There is no requirement forcing consistency, so a 20F from one brand and a 20F from another are not necessarily measuring the same thing.

The exception is the Featherstone Outdoor Moondance 25 Top Quilt, listed at 652 g, 23.0 oz, 850 fill power, list price $269.99, with an ISO 23537-1 tested rating of comfort 36F and limit 26F. That is the only genuinely tested rating in this entire comparison. Comfort is the temperature at which a standard sleeper stays comfortable through the night. Limit is where a standard sleeper is curled up and enduring rather than sleeping. They are different questions and the gap between them is ten degrees.

Now reread the rest of the list. Every other product prints one number with no standard attached to it. If a tested quilt comfort figure lands 11F above the number in its own model name, the reasonable working assumption is that untested single numbers are quoting something closer to a limit figure than a comfort figure. Plan a 10F margin on any untested rating and you will sleep better than the label promised.

A quilt deletes the back panel and usually the full-length zipper, on the correct reasoning that down crushed flat under your body weight is doing almost no insulating work. That is real weight removed for essentially no thermal loss, which is why the lightest products here are quilts. The catch is that it only holds if the pad underneath is genuinely carrying that load.

Here is the useful asymmetry. Sleeping pad R-value is measured to a common standard, ASTM F3340, which the industry adopted specifically so that R-values would be comparable between brands. Two pads that both say R 4.5 have been through the same test. Two bags that both say 20F, as this comparison shows, have almost certainly not. So the most trustworthy number in your entire sleep system is printed on the pad, not on the bag.

Practically, a 20F quilt over an R 2 pad is not a 20F sleep system, no matter what either label says. Common guidance is R 4 to 5 for three-season use and more once the ground is frozen. Pair the pad to the coldest ground you expect first, then argue about which quilt goes on top.

Nunatak Arc UL 20 is the lightest thing here at 510 g, 18.0 oz, 850 fill power, rated by the manufacturer to 20F, list price $420.00. Reason to skip it: the Enlightened Equipment Enigma 20 is listed at 539 g with the same 850 fill power and the same 20F claim, at list price $335.00, so you are paying a meaningfully higher list price for 29 g. The Enigma 20 and Revelation 20 are both listed at 539 g, 19.0 oz, 850 fill, 20F, list price $335.00. Reason to skip either: they are identical on every published spec I have.

Katabatic Gear Flex 22 is 553 g, 19.5 oz, 850 fill power, rated by the manufacturer to 22F, list price $420.00. Reason to skip it: it is 14 g heavier than the Enigma 20 with a 2F warmer claimed rating and a higher list price. Enlightened Equipment Revelation 10 is 652 g, 23.0 oz, 850 fill, rated by the manufacturer to 10F, list price $370.00. Reason to skip it: if your nights rarely go below 20F you are carrying 4 oz for margin you will not use.

Featherstone Outdoor Moondance 25 Top Quilt is 652 g, 23.0 oz, 850 fill power, ISO 23537-1 tested to comfort 36F and limit 26F, list price $269.99. It is the only tested rating here and the quilt I would point a data-minded buyer at first. Reason to skip it: a tested comfort of 36F is a summer quilt in New Hampshire. Hammock Gear Economy Burrow 20 is 709 g, 25.0 oz, 800 fill, 20F claimed, list price $239.95, the lowest list price here. Reason to skip it: 170 g heavier than the Enigma 20 for the same claimed rating.

Marmot Hydrogen 30 is 620 g, 21.9 oz, 800 fill power, rated by the manufacturer to 30F, list price $389.00. Reason to skip it: the lowest fill power of any mummy here and the warmest claimed rating.

Sea to Summit Spark SP III 18 is 620 g, 21.9 oz, 850 fill power, rated by the manufacturer to 18F, list price $529.00. Same listed weight as the Hydrogen 30 with a claimed rating twelve degrees colder. Reason to skip it: the list price is the second highest here. REI Co-op Magma 30 is 624 g, 22.0 oz, 850 fill, 30F claimed, list price $339.00. Reason to skip it: 30F is a narrow usable window in the Northeast outside high summer.

REI Co-op Magma 15 and Mountain Hardwear Phantom 15 are both listed at 822 g, 29.0 oz, 850 fill power, rated to 15F, at list price $389.00 and $600.00. Reason to skip both: at 822 g you are 283 g above the lightest quilt here for a claimed five degrees.

The Magma 15 and Phantom 15 pair is the uncomfortable one. Identical listed weight, fill power, shape and claimed rating, and list prices of $389.00 and $600.00. I am not calling the more expensive one a bad product. The differences almost certainly live in fill weight, shell fabric, baffle construction and warranty, and not one of those is published in the specs I am working from. If you are buying on published specifications, ask the maker for fill weight before spending the difference.

Contrast that with the Hummingbird UL 20 and Magma 30, both listed at 624 g. There the spec sheet does explain the gap: 950 versus 850 fill power, a 20F versus a 30F claim, list price $509.00 versus $339.00. When the published specs account for a price difference, the difference is probably real.

Choose the pad first, because its R-value is measured to a common standard and your bag rating is not. Then choose shape: a quilt if you move around and sleep warm, a mummy if you sleep cold or want a hood. Only then argue about the rating number, and assume every untested figure here is optimistic by something like ten degrees. The one product that has been through ISO 23537-1 came out with a comfort rating 11F above its model name, and that is the only calibration point any of us have.

Three picks with their downsides attached: the Featherstone Moondance 25 at list price $269.99 for the buyer who wants a number they can trust, accepting that a tested comfort of 36F makes it a summer quilt. The Enlightened Equipment Enigma 20 or Revelation 20 at list price $335.00 as the weight-to-list-price midpoint, accepting an unverified claim. The REI Co-op Magma 15 at list price $389.00 for an enclosed bag on colder nights, accepting 822 g. The pad under any of them still decides whether they work.

Is a 20F quilt as warm as a 20F bag? On the published numbers you cannot tell, because in most cases neither figure has been tested to a common standard. Structurally, a quilt removes the back panel on the reasoning that down crushed under you does little, so the pad must carry that share. Over an adequate pad the two can be comparable. Over a low R-value pad the quilt loses first.

What do comfort and limit mean on an ISO 23537 rating? Comfort is the temperature at which a standard sleeper stays comfortable through the night. Limit is where a standard sleeper is curled up and enduring rather than resting. The Featherstone Moondance 25 is the only product here with a tested rating, at comfort 36F and limit 26F, and that 10F gap is why a single untested number tells you so little.

Does a higher fill power number mean a warmer bag? No. Fill power measures how much loft one ounce of down produces, so it is a quality measure of the down itself. Warmth depends on total loft, which is fill power multiplied by the amount of down used. Compare total loft and the complete bag design rather than treating fill power alone as a temperature rating.

Why is fill weight in grams not listed here? Because it is not published in the specifications I am working from, and I will not invent a number. It is the single most useful missing figure. Most manufacturers will tell you fill weight if you ask customer service directly, and for any purchase over a few hundred dollars it is worth the email.

Are the prices in this guide current? No. Every figure here is the manufacturer list price and nothing more. This comparison does not track current or street pricing, does not follow sales or discounts, and does not keep price history.