Cumulus X-LITE 300 – Review

I wanted to write this as I was extremely impressed with the sleeping bag, it has all familiar quality of materials and construction that I have found with my Quilt 350 and performed well in various situations.

I have used the bag exclusively over the last few months in order to give a fair perspective.

First of all I would like to say that I do not own this sleeping bag. Cumulus was kind enough to loan the bag to a Facebook group of which I am one of the admins. The bag has been used and tested by a number of members, myself being one of them.

I have not been paid for writing this, nor will I be recieving anything in return once I hit publish.

Specs from Cumulus

Specs of the bag I had to test

Total Weight in Stuff Sack – 478g
Lowest temp used – 0C
Highest Temp used – +9C
Internal Length, measured from the center of footbox to where the bag would meet the chin, 204cm

When the bag arrived, as I would with any second-hand bag or quilt I washed it and treated it with Nikwax Down Proof. I have done this to all my down gear from new.

Not only does it remove any sweat and dirt, I have found it makes the down loft better in some cases.

What do you get?

Cumulus supplied the bag with a mesh storage sack as well as a nicely finished stuff sack. I received the same with my Quilt 350 and understand that these are standard with all Cumulus products.

The bag will also come with material information and care instructions.

What am I comparing the bag to?

Something that reviews often lack is a direct comparison to equivalent or similar gear.

Cumulus X-LITE 300, 900 EU Fill Goose Down, 479g – £275

  • Alpkit Pipedream 400 – 750 EU Fill Goose down – 865g – £215
  • Cumulus Quilt 350 (closed footbox version) – 850 EU Fill Goose Down – 585g – £205
  • Enlightened Equipment Revelation 30F/-1C- 850 US Fill Power – £219 + Delivery & Import Duty.
  • My MYOG Quilts

I am a fairly warm sleeper. I used my Alpkit Pipedream down to -8C without issue wearing only baselayers. Similarly, I find my Cumulus Quilt 350 a little too warm above 0/2C.

When I owned the Pipedream, I used an EXPED Winterlite pad during winter, all other bags and quilts have been used with a Thermarest Xlite mat.

Build & Construction

The X-LITE is very well made, using high quality materials and extremely high quality down.

The bag itself is constructed from Toray Airtastic fabric in a lime green colour with matching stitching. The Airtastic fabric is very soft to touch and feels very nice against the skin. I’ve not used anything made using this fabric before and although its very lightweight, 19g per metre square it seems to be pretty durable and the DWR treatment works well to protect the down inside.

The zipper is a YKK no3 and runs down the right hand side of the bag I have, this can be customized when purchased from Cumulus. opening the back up just over two thirds of the way and having two sliders it provides both easy entry/exit as well as good venting options. I did find that the internal zip baffle can easily be caught by the zip sliders which can be annoying.

Trapezoid baffles independently filled front and back allow the down to loft nicely and I found no drafts or cool areas. When the bag first arrived some of the baffles had less down than I expected however due to having a higher fill power than I am used to and the quality of the down I have had no cold spots during use.

The fill of the bag seems fairly consistent on the back, but there is more down in the torso at the front and footbox area than the leg area.

Although I washed the bag before using it, I did a spray test on the bag beforehand to test the DWR. I was impressed with the beading and no water appeared to make its way thorugh the outer fabric or effect the down inside.

The stitching is very nice, matched colour thread and very neat and no pulled or loose threads that I have found.

Size and Fit

I am 6ft and weigh 86.4KG. I found the bag a fairly tight fit with its alpine style design and cut. I still had plenty of room to move around and for my arms to move freely but I am more accustomed to quilts these days.

The hood, for me is a little on the small size but is filled with a nice amount of down which boosted the comfort of my pillow. Hunkered down, the hood did fit but felt a little restrictive for me.

I found the footbox design very roomy for my size 11UK feet with plenty of room to move them around and store gear such as my sawyer water filter, phone and battey pack on cooler camps.

When I used the bag in Scotland the air temperature was +6/7C. I opened the zip fully and used the bag as a quilt. The shape of the bag works very well for this, effectively giving a sewn footbox with a nice wide quilt like top.

In Use

One of the first things I do when using a down bag or quilt, once pitched is to take the bag/quilt out and let it loft. I found the bag took a little longer to fully loft than my Quilt 350, maybe an extra 5-6 minutes.

For the size of the bag and temperature rating, it packs away to a very small size within the supplied stuff sack. You could easily compress it further but I do not like overcompressing down and tend to either use the supplied stuff sack or an XL MLD Cuben Dry bag to store my bags/quilts.

As I said above, I sleep very warm and I was no different with this bag. Judging on the temperatures I used the bag, I would say Cumulus’s rating of +2 to -4C spot on for the average user and a warm sleeper like me would easily be able to use the bag in comfort to 0C or just below.


For me the X-Lite 300 is a great allrounder, you could easily use this bag 3/4 seasons, being able to open the bag up and use it as a quilt is a big bonus for me. You can do this with all sleeping bags I know but the design of the X-Lite makes it feel more usable as a quilt than many. The temperature ratings are accurate in my opinion and even a cool sleeper would be comfortable to freezing without too many layers.

The build, construction and design of the bag is very good, high-quality materials used in a well thought out way to maximize on the benefit they offer.

My only critisisum would be the zip baffle, I found that I kept catching it with the zip and this became a little annoying.

  1. I like the way you write your reviews and I also like as pointed out that you do not own this sleeping bag and that your not getting anything from writing this. Too many reviews are biased now with people being given gear and writing favourably about it in order to keep the freebies coming.

    I have the same one, the 300 and agree with everything you have said. The sleeping bag is pure quality and the down used is far better than anything I have encountered with years of using Rab, PHD and Enlightened Equipment sleeping gear. Anyone looking for a high quality sleeping bag should seriously consider cumulus. For the money, you cannot get better in my experience.

    Keep up the good work.

    P.S have you stopped Youtube?, you’ve not posted in a long time.

    1. Thanks Tom, yes its a lovely bag and if I used sleeping bags more, I would probably get one and use it year round but I prefer my quilts now. Youtube wise, yes I still post now and then. ATB, Dave

  2. Do all the bags have that 900 down now?

    1. Not all of them but you can create a custom bag with them and you can discuss custom options via email ect.

  3. Hey, so I’ve been thinking about pulling the trigger on the 350 quilt but you might have changed my mind with this review. Am I right in thinking the sleeping bag has a similar comfort rating but for less weight? Or is the quilt warmer? … I sleep pretty cold though. I’m looking for something I can use in a variety of climates 🙂

    1. Hi Claire, thanks for your comment. For me, the quilt and bag offer similar comforts levels for most people, I personally prefer a quilt over a bag and sleep warm, a quilt allows me to cool off easier as well as hunker down. Cumulus will custom build most things so if like me you prefer quilts, you could ask them to make you up a 350 with 900 fill?

      ATB, Dave

  4. Hi, any reason why you would choose the quilt version above the x-lite version? The x-lite seems lighter than the quilt version, so isnt the x-lite simply a better product than the quilt?

    1. Hi Dean, thanks for your comment
      The X-Lite was on trial from Cumulus, I personally prefer quilts over bags.
      ATB, Dave

  5. Hi!
    Thanks for the review.
    Is it the M size that you tested ? I’m 1m84 and 70kg, so I wonder if M is enough for me or if I should go for a L.
    I’m also thinking about choosing pertex quantum pro as external textile.

    1. Hello, at the time of testing there was only one standard size. I believe this would now be classed at the large available in the DIY section for Cumulus. ATB, Dave

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