sleeping

Western Mountaineering Ultralite vs Alpinlite

Last updated: August 17, 2022 by Canberk Koksal

If you're looking for a top-notch quality, lightweight, buy-it-for-life, made in USA backpacking sleeping bag, and you're stuck between Western Mountaineering Ultralite and Alpinlite, you don't need to worry because I can almost 100% guarantee you that you absolutely can't and won't go wrong with either of them. Both are warm, comfortable, lightweight, packed small and versatile - with one small difference:

Ultralite is just a slimmer version of the Alpinlite.

Everything else is the same although you get a 2 oz less weight and smaller packed size with the Ultralite's slimmer cut (see their manuals here [PDF]).

But how do you know which one you should get? In this post, I've gathered all the information to consider when deciding between Alpinlite and Ultralite.

If you're taller than 6'6"...

You can only get Alpinlite 7' because the longest Ultralite is only 6'6".

First of all, as long as you aren't over 6'6", you probably won't experience any problem in fitting inside either of these bags (regardless of your shoulder width, build, etc). If you're a side sleeper, Alpinlite | No products found. is probably a better choice for you since its baggier cut allows more comfort for side sleepers. For all the others, Ultralite | No products found. is probably the better choice since its slimmer cut brings nearly smaller packed size (for sizes over 5'6" in length) and ≈2 oz of weight reduction.

But, again, both bags are top tier and I'd highly doubt you'd regret buying either of them.

Also, if sleeping on your TUMMY is VERY important for you

Don't get either of these mummy bags and check out Nemo Disco/Rave/Riff/Jam spoon shaped sleeping bags which are specifically designed for this purpose. But beware - they aren't made in USA unlike Alpinlite and Ultralite.

I talked to the WM Customer Service (screenshot below) and concluded this once more: Ultralite is just a slimmer version of the Alpinlite. Everything else is identical!

Click on image to enlarge. Below I shared the attachment the rep provided.

Here's the mail attachment: https://outdoorcrunch.com/wp-content/uploads/2019/02/WM-2018-Specs-1.jpg

Now, the differences are as follows on paper:

Differences between Alpinlite and Ultralite

Width: Alpinlite is 4-5" (depending on the bag sizes - see attachment by the rep above) wider in shoulders & hips, and 1" wider in foot
Weight: Alpinlite is 1-2 oz heavier (depending on the bag sizes - see attachment by the rep above)
Fill weight: Being wider, Alpinlite needs 2 extra oz of down to offer the same warmth as Ultralite
Packed smaller: Sack size of Ultralite is XS - whereas that of Alpinlite is S. However, 5'6" Alpinlite also comes in XS sack size.

And now let me translate the consequences of these spec differences.

Girth

Let's begin with the most important difference.

Click on image to enlarge.

Extra girth of Alpinlite has a few advantages over Ultralite:

Sleeping on your side/tummy (for some, even on your back!) is more comfortable
You can stuff valuable or self-defense gear inside (be a lone female) when needed
When it's below 20 F (which is the min advertised temperature limit for both bags) you can stuff pre-heated rocks inside for extra warmth, or you can wear more layer and still sleep inside comfortably

What about the downsides of extra width of Alpinlite?

Depending on the bag size you get, it's 1-2 oz heavier than Ultralite
Unless you get the 5'6" size, stuff sack is 1 size larger than Ultralite (S vs XS) (more on this later)

Wait, so the extra dead air in Alpinlite doesn't take longer to be heated?

Technically speaking, it should (does), but it really isn't noticeable at all. Inner volume increase really isn't substantial when it comes to heating speed.

I'd clear this out in my mind: Regardless of your build/gender/weight/height/age, you'll experience the same warmth inside these bags.

Which brings me to my next point...

Warmth

Although the warmth provided by these bags are identical, I'd like to talk about some shared features of these bags.

Fill Weight

If you're unaware what fill weight means: It's the weight (amount) of down used in the bag.

If you're unaware what down means, it's the feather that keeps duck and goose warm. As a thermodynamics law (entropy), the heat will always diffuse a colder region in order to achieve equilibrium. In that case, these feathers (down) traps the air inside and prevent the heat from escaping the heat source (which, in our case, is human body).

We humans use this down in sleeping bags, jackets, booties and in everything else we'd like to insulate and keep warm as long as possible.

Fill weight (amount of down) is directly proportional to the warmth provided by a sleeping bag.

Alpinlite has 2 extra oz of down. But! That does NOT mean that Alpinlite offers more warmth! Since it's wider, it has more material and therefore needs to have more down by right to provide the same warmth as Ultralite.

The warmth provided by these bags are identical.

What about Fill Power?

If you're unaware, fill power (FP) is what, ultimately, defines the quality of a down. It's rated on a scale from around 500 up to 900. A 500 FP down means that when the down is at rest, it'll spread to 500 cubic inches. The higher the volume it spreads, the more air is going to be trapped inside the down.

This way less heat will be able to escape your body, and as a result, you'll feel warmer.

Most other manufacturers equip their gear with downs with different fill power: 500, 600, 800. Although it certainly is possible to provide a fair amount of warmth using a low-end FP (low quality) down, it certainly will take a lot more of it and hence the heavier weight.

Western Mountaineering, on the other hand, always uses the finest quality down. They never use even medium-high quality down (below 800 FP). According to their manuals [PDF], their laboratory tests conclude their down quality over 850 FP. This is how they achieve low weight, small packed size AND incredible warmth all at the same time (hence their premium price range). This is only attainable with a super high FP - like 850+.

So if Alpinlite and Ultralite both offer 850+ FP (very high) down quality, that means they're identical. Then why am I talking about it?

So that you know both use top-notch down quality
It'll be important when I talk about the storage of these bags

Conclusion: Both bags provide equal warmth.

Also, these bags are rated at 20 F - which means they're going to provide enough warm at temperatures as low as 20 F.

But...

What if you use them below 20 F?

This value (20 F) is not only conservative, but also indicate the minimum temperature a 25 year old, 5'3" (1.6 m) & 130 lb (60 kg) female can sleep comfortably inside the bag.

It's based on women since they sleep colder than men.

Although these are 3 season bags, they will still feel pretty warm even below 20 F. For even further below that, you can check out my 3 most effective tips to heat a tent/sleeping bag without electricity. The "heating rocks" tip would work the best with Alpinlite rather than Ultralite since it has more room inside to stuff items.

Weight and packed size

Weight

As you see, depending on the model, Alpinlite is 1-2 oz heavier than Ultralite:

Click on image to enlarge.

To me (not really an ultralighter and more like a fairlighter) these weight reductions of UltraLite wouldn't really worth sacrificing the extra comfort and customization benefits of the AlpinLite.

Packed size (stuff sack)

Here's how XS and S stuff sack sizes compare:

Click on image to enlarge.

As you see in the chart above, S size is 8 (DIA) x 15 inches, whereas XS size is 7 (DIA) x 13 inches. "Compressed volume" column you see in the above chart isn't important since both bags come with their stuff sack and you'll be using them for transport.

Another thing to consider here, as mentioned earlier, is the 5'6" size of these bags: They both come in XS stuff sack. So, if you're planning to buy the 5'6" size of either of these bags, Ultralite loses its packed size advantage!

Regardless...

ALWAYS push your sleeping bags to very deep into their sacks - but they should stay there only when transporting! Otherwise, your sleeping bag should always be stored in the storage bag - which is baggier and allows the down to breathe and stay lofty. This is very important for the life of your sleeping bag.

For other maintenance and FAQ, this guide by WM can be a good read for you.

Other shared features of these bags

Both bags offer the following.

Continuous baffle

This is what I really like about these bags as it allows great versatility.

Continuous baffle allows shifting the down at the top of the bag to the bottom of it (and vice versa) and as a result adjusting insulation (and hence, warmth) to your taste. What I really like about this is that you can basically sleep a lot more comfortably during warmer summer nights.

Therefore, unlike most other bags, you can use these bags during hot summer nights AND cold winter nights.

Draft tube

Draft tube hinders the heat leakage from zippers.

Click on image to enlarge. As you see, the feature in green box isn't offered some WM bags. But what does it do?

This draft tube helps the downs protect their full loft throughout the entire bag surface. This way, in terms of heat leakage, these zips aren't the weakest spot of a bag anymore.

Full collar

What WM calls "full collar" is the continued portion of draft tube:

Click on image to enlarge. Full collar is the portion of draft tube around the neck.

Just like draft tube, full collar also prevents the heated air from escaping the bag. But unlike around the zipper, full collar prevents the it from escaping it around your neck.

As you see, when full collar and draft tube is combined, you get a highly insulated sleeping bag.

Left or right zip?

As you see on Amazon, both bags come with either left or right zips. To me, this is only important if you own an asymmetric 1P tent which offers only one door. Let me tell you why.

Chances are, with that type of small tent, you'd probably want your feet pointed towards the end of the tent with smaller area while sleeping. So, with this sleeping bag position, if the door of your tent is positioned to the right of your sleeping bag, you'd better get the bag with right-zipping. If the door of your tent is positioned to the left of your sleeping bag, you'd better get the bag with left-zipping!

Also, if you're looking for an air mattress for camping too, this post of mine can be a good read for you.

Conclusion

In summary, I'd recommend the Alpinlite | No products found. to all side/tummy sleepers and/or bigger fellas. If you aren't one of these, the ways you can leverage the extra internal room can still be substantial: You can always stuff valuable and/or self-defense gear inside when needed (especially if you're a lone camping female). When it's below 20 F (comfort limit for these bags) outside, you can stuff pre-heated rocks inside for more warmth, or wear extra layers.

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If you're a slim person, though, and you aren't really a side/tummy sleeper, the extra room of Alpinlite could be a downside as it adds to weight. If you'd gladly take the 2 oz of weight reduction and smaller packed size (for sizes over 5'6") over all these benefits, Ultralite | No products found. is the way to go for you.

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Lastly, my other post how to sleep comfortably in a tent can be a good read for you.

I hope this review was helpful for you to understand which WM sleeping bag would be the best choice for your needs. Feel free to ask me any questions, provide feedback and I'll be happy to respond in the comment section below if it's within my knowledge.

Thanks a lot for reading. Happy trails.

Nemo Riff/Jam vs Disco/Rave (15 & 30): Only ONE Difference

Last updated: August 17, 2022 by Canberk Koksal

Rave 15 (see image) and Disco 15 are as warm as Jam 15 and Riff 15! Lower FP does not always mean lower warmth... I mean, as long as you're using your sleeping bag like everyone else in this world and not like shown in the picture!

If you're a cold, side (or tummy) sleeper looking for a backpacking sleeping bag, don't get a regular mummy sleeping bag and instead check out Nemo's Riff and Disco models. Their spoon-shaped design allows greater room around your legs and shoulders without sacrificing warmth, which solves the problem for cold, side (or tummy) sleepers. You can see their manuals here [PDF].

But... which one should you get? Disco or Riff (or, for women, Rave or Jam)? 15 or 30? Reg or Long? This post is all you need for the answer.

In summary, if extra 2-4 ounces and an inch longer packed size aren't huge concerns for you, Disco 15 (or Rave 15 for women) will work perfectly fine! Otherwise, Riff 15 (or Jam 15 for women) would be a better choice.

Because, most importantly, the warmth provided by Riff/Jam 15 is equal to the Disco/Rave 15, and the warmth provided by Riff/Jam 30 is equal to the Disco/Rave 30!

Nemo might be on sale now at REI

So I'd recommend you to check out Nemo's very own sale page at REI before buying.

Before I get to the bolts and nuts, I'd like to say that I really don't see why would anyone go for 30 F deg models of these bags. Decrease in price doesn't worth the warmth sacrifice - even if you aren't a true cold sleeper (more on this later)...

So, as you see, their only difference is:

Weight and packed size.

I talked to the NEMO Equipment Customer Service (screenshots below) and made hours of research to conclude that Riff/Jam Series DO NOT provide more warmth than Disco/Rave Series!

Click on image to enlarge. I know the rep didn't make some points clear enough. That's why I kept asking him and shared the screenshots below.

In fact... You know what? Technically speaking, Disco/Rave provide more warmth than Riff/Jam (although the difference is pretty much not noticeable)! More on this later.

Now on paper, their differences are as follows:

What does Riff/Jam offer in addition to Disco/Rave?

Higher down quality (so called fill power): 800 FP is used in Riff/Jam compared to Disco/Rave's 650 FP
Fill weight (so called fill power): Less down is used in Riff/Jam and hence it weighs less
Thinner shell fabric: 20D vs 30D - which is slightly lighter & more compressible but also slightly less durable
Weight: Slightly (2-4 ounces) lighter
Packed smaller: 0.5 inches shorter (in length - not dia) when packed

I didn't provide the exact numbers to these specs because they differ between 15-30, male-female, reg-long models.

And now let me translate these.

Fill Power Difference: 650 FP vs 800 FP

Fill Power (FP) is the measured loft of down. In other words, it's the end size of the down when it's in rest, e.g. "fully expanded".

For example, an 600 FP down means that 1 oz of that down can cover 600 cubic inches. This, in other words, is what defines the quality of down. Higher FP means more warmth for its weight. Because more air will be trapped inside the down and will work as an insulator:

Generally speaking, for sleeping bags, over 750 FP (to my knowledge, they go up to 900 FP) is considered top notch quality down (Riff/Jam) whereas 600-750 FP as "medium" quality (Disco/Rave).

Now when I said "for its weight" above, what I'm trying to say is that Fill Power is NOT the only thing that determines the ultimate warmth of a bag. The amount of down is also very important - which is called "fill weight".

A product filled with 500 FP down can provide the warmth a product with 800 FP down does. But it certainly will be A LOT HEAVIER since it requires more down!

And that, kids, is what causes the key difference between Disco/Rave and Riff/Jam products. Disco/Rave is filled with more 650 FP down, whereas Riff/Jam is filled with less 800 FP down.

As a result, Riff/Jam weighs substantially (2-4 oz - depending on the model you get) less and its packed size is smaller.

But what about their ultimate warmth? Does Jam/Rave's 20.5 oz 800 FP down provide more warmth than Disco/Rave's 22.5 oz 650 FP down?

Short answer: No. They're identical.

Now when we get to the long answer - I don't know the math behind these calculations, but I do know something more useful: EN 13537.

It's a standard metric used for the warmth provided by a sleeping bag. It basically takes into account ALL the factors that affect the warmth of a sleeping bag and rate them on a scale. Lower EN Rating always means more warmth!

Now let's see where Disco/Rave and Riff/Jam stand...

EN Ratings

EN 13537 is the warmth standard for sleeping bags, and there are different EN ratings.

EN Comfort

For example, EN Comfort shows the minimum temperature a 25 year old, 5'3" (1.6 m) & 130 lb (60 kg) female can sleep comfortably inside the bag. It's based on women since they sleep colder than men. Lower EN Comfort means higher warmth.

EN Lower Limit

EN Comfort isn't end all be all.

There are other measurements such as EN Lower Limit - which shows the minimum temperature at which a 25 year old, 5'8" (1.73 m) & 160 lbs male can sleep for 8 hours in a curled position without waking up. Similar to EN Comfort, the lower the EN Lower Limit, the warmer you'll feel inside the bag.

There are also EN Upper Limit and EN Extreme, which I won't go into detail, so you can check Wikipedia for that matter.

Now let's see where our two (*cough* four) bags stand:

As you see, judging by the EN standards, Disco/Rave provides even more warmth than Riff/Jam! But the difference is pretty much not noticeable, so I don't really agree with the "if you sleep on the colder side get Disco/Rave" part.

Warmth debate concluded: Disco/Rave 15 will provide equal warmth to Riff/Jam 15. Disco/Rave 30 will provide equal warmth to Riff/Jam 30.

But... Which one should you get? 15 or 30?

Disco/Rave Riff/Jam 15 vs 30

Once more, I'd like to repeat that the warmth performance of the bag you get will be determined by whether you get the 15 or 30 model. Whether you get Disco/Rave or Riff/Jam will determine the weight and packed size of the bag - not its warmth.

15 will perform well in temperatures as low as 15 F (-9 C) and 30 will perform well in temperatures as low as 30 F (-1 C).

I'd also like to say one more time that I really don't see why would anyone go for 30 F deg models of these bags. Decrease in price doesn't worth the warmth sacrifice - even if you don't sleep really cold.

If you decide to buy one of these bags, buy the 15 F model!

Shell Fabrics: 20D vs 30D

Shell fabric isn't an insulator-specific term.

In our case, Riff vs Disco, the difference is that Disco uses 30D Nylon Ripstop w/ DWR whereas Riff uses 20D Nylon Ripstop w/ DWR. Higher denier (D) means thicker fabric, and therefore Disco is heavier & more durable compared to Riff, whereas Riff is not only lighter but also can be compressed further although it has slightly less durability.

On the other hand... These are from very scientific standpoint, guys. In practice, the difference is so subtle that priority of shell fabric thickness in the durability department is waaaay behind how you treat the bag or how long you use it.

That's why I change my argument to this:

Both are great fabric thicknesses (deniers) for sleeping bags and you won't notice a difference in practice.

Besides shell, their Footbox (both 40D Nylon Ripstop OSMO w/ DWR) and Lining (both 30D Nylon Taffeta w/ DWR) fabrics are identical.

What about the size? Reg or long?

This mostly comes down to your height. They're designed for the users as follows:

Men's regular models: Men below 6' (183 cm)
Men's long models: Men above 6' (183 cm)
Women's regular models: Women below 5'6" (168 cm)
Women's long models: Women above 5'6" (168 cm)

Besides height, I'd like to mention one more important thing here. When I was talking about most effective ways to heat a tent without electricity, one of my tips was to heat some rocks by the camp fire and place them inside your tent or sleeping bag (away from your stomach/kidneys).

So, if you think you might use this tip and if you're borderline between Reg/Long models (e.g. if you're a 6' male or a 5'6" female) it might be a good idea to go for the long model.

Other shared features of these bags

They all come with the following. Nemo honestly offers all the features you can ask from a sleeping bag.

Cotton storage bag and a compression stuff sack:

Blanket Fold for comfort and temperature regulation:

Thermo Gills to tune the ventilation and inner temperature for your taste:

Bottom zippers offer even further ventilation adjustment. That's why these bags are also perfect for summer - there's always something you can do to increase the air flow inside when you feel too hot:

Also as you see, all bags are left zippered.

Integrated pillow pocket: This Nemo Fillo Inflatable Travel Pillow is compatible with this pocket so if you prefer buying this one you don't have to worry about its fit.

Integrated stash pocket. Perfect if you like spending time with your smartphone right before sleeping:

A very well thought out feature I like: Bottom of these bags are more waterproof (waterproofing isn't black and white! Some fabrics are more waterproof than others and vice versa).

Because of this fact, while sleeping, your feet (the closest body part to this highly wet part of tent) is always more prone to get damp and hence this more waterproof design around that area:

If you're a cold, side (or tummy) sleeper looking for a backpacking sleeping bag, these designs are for you. Don't get a regular mummy sleeping bag!

If you're also looking for an air mattress for camping, this post of mine can be a good read for you.

Conclusion

So, in short, if weight and packed size aren't huge concerns for you, absolutely get the Disco 15 (or Rave 15 for women). If the weight and size reductions are substantial for you, Riff 15 (or Jam 15 for women) would be a better choice.

I wouldn't really recommend 30 F models for any of these bags.

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Lastly, my other post how to sleep comfortably in a tent can be a good read for you.

I hope this review was helpful for you to understand which sleeping bag would be the best choice for your needs. Feel free to ask me any questions, provide feedback and I'll be happy to respond in the comment section below if it's within my knowledge.

Thanks a lot for reading. Happy trails.