Cumulus X-Lite 300 review

Introducing “Cumulus Equipment” a Down feather product manufacturer from Poland.

Cumulus has an extensive range of Down filled products and most notably a huge range of Down Sleeping bags and plenty of scope to customise them and its very insightful “customising” them on their website. Nope Id never heard of them either, an unknown company to me, and honestly not being in the EU are quite expensive to purchase from, but its worth it as their products really reflect their practical experience.

Over the years Ive accumulated a few of sleeping bags, including a Snugpack Elite 4 (minus 10˚C rated) and Deuter Dream Lite 500 (+13˚C rated) which together with my Sea2Summit Thermolite reactor inner and Goretex Mummy outer gives me a fantastic range of sleeping condition choices from Sodwana in January to Kilimanjaro. But theyre quite heavy and or bulky (I also over the years and in the family have a Dueter Orbit [cooler than] 9C comfort and two KWays)

I chose the Cumulus X-Lite 300 as the most suited bag to Southern African Winter, Altitude and Desert hiking conditions (Im calling it WAD Hiking) and specifically because it’s the lightest bag comfort rated in the 2˚C to 5˚C zone. (There is an RAB Bag that’s nearly twice the price and is supposed to be lighter for the same thermal rating but how that’s actually possible using less and lower quality down with a heavier material is highly questionable)

At Cumulus it is possible to extensively customise the sleeping bags and I should have gone for a full length zip to make it a bit more friendly in warmer conditions in the 7˚C-10˚C range. Above 12˚C it is a bit too warm and Ive unzipped completely lying on the air mattress with my feet in the foot pocket inside my rucksack to keep the foot pocket from lofting and using it as a Quilt.

The Coolest Ive had it so far is 3˚C on a miserable night and with an air mattress on top of a 1cm foam mat - I was warm in cotton Tshirt and Boxers. – Im confident going cooler especially if I wear thermals but will keep the thermal liner and goretex outer just in case when experimenting.
In the 5-7˚C range on a dry riverbed in Kruger it was absolutely perfect I was toasty warm whereas previously in my +13˚C bag with the Thermal liner by 4 am I was frozen wearing all the clothes I had with me.
In the June Kgalagadi where water froze overnight It was at its comfort limit on a bed mattress in a tent

As a wriggler, I chose to stick with their standard filling ratio of 55/45 (front to back) down fill rather than opt for a 65/35 or 50/50 and opted for the non Hydrophylic down which is 900fp (Cumulus go to lengths to describe their ethical sourced free range Goose down sourced locally, which have access to water as being the highest lofting down available, and Ive no cause to query this, but their down is worlds apart from the typical good quality 650fp down Ive got elsewhere.)
Speaking of lofting – Ive got a timelapse need to figure out how to link that here. Its incredible how it lofts from its most compressed state to it fully fluffed up, much more so when youre in it.
Its made up of 33 baffels that are sewn together in a manner that prevents down from moving around vertically along the bag length and also in an overlapping type design that doesn’t leave any cool spots from down moving within a cell.

They supply you with two storage bags, the tiny Toray Airtastic compression sack which squeezes it down to a volume of 2.6litres and a general storage airy mesh bag of about 30 litres. In the practical world when Hiking I store the sleeping bag inside a waterproof 5 litre roll sack which then compresses further inside my pack. I just wont have a wet sleeping bag as a consequence of falling in a river [ever again] and then being thoroughly miserable
Where this rapid lofting makes a difference is when youre rolling over, the cooler compressed down that was under you lofts up and warms up quite quickly so you stay warm

It is a Mummy bag with an angled and tapered box shaped foot pocket perfect for weary feet to not get pressured into twisting as one gets with flat sleeping bags; its genuinely comfortable.
Ive found that I can cross my feet and get a bit of a sense of legs not trapped together in the mummy shaped bag – something that isn’t so easy in flat mummy bags.

The 3mm YKK 2/3 length [baffled] zipper comes to about my knees. 3mm zips are a little bit finicky rather than the usual 5mm zipper so you need to be a bit aware when zipping and unzipping. Ive yet to have a snag on the zip, which is quite something, and Ive not noticed the zip digging into me when I roll around to sleep on my side on top of the zip.
The zip Baffle lofts nicely and forms a seal on the zip and extends 12cm past the bottom of the zip, so you certainly don’t notice any air coming in the bag nor any cold spots along the zip length. With the zip ending at the knee any draught that might come in at the bottom of the bag doesn’t go to your toes however Ive not noticed it (and this isn’t helpful when its hot and the zip is open)

There is no chest/shoulder baffle but the hood is plenty deep enough and they have included a bungee chord for the chest side closure and a flat strapping type drawcord for the hood area. It’s a small detail but at night you can fine tune the closure to your most preferred manner easily using touch alone with the flat strap providing a locked position and the chest side altering its length so you don’t end up fiddling with the hood comfort shape just set it once. Its actually inspired at 3am when you come back from a pee wanting to get snug, and before that the bungee means you can get an arm out quicker

Made from Toray Airtastic which is lighter and more comfortable than Quantum Pertex but presumably more fragile in test conditions, in the real world whatever you’re doing to tear the Toray would also tear Pertex. Pertex Quantum can be specified as a customised option for increased durability (but defeats the ultralight purpose)
But oh my word is Toray Airtastic comfortable, noticeably softer than Pertex and apparently as the worlds lightest Downproof fabric being comfortable too is a superb choice for sleeping in.
The colour is an almost translucent black material which looks bruised blue in the light, it is quite attractive and is also very quiet no crinkly noises and not too slippery either.

Logos and labels are kept to a minimum as befitting its weight goals theres no internal pocket either. The Logo is embroidered on the bottom of the foot box and the label inside the zip states its got a lifetime warranty and the bags are hand numbered with a space for you to enter your name – nice touch

I am 5ft11” [180cm] tall and quite “broad” I find this is a snug fit width wise, not considered too tight; I can still move my arms around my body and I don’t regret not opting for the extra width option. Typical hiker builds will find this roomy I played Prop not Wing…. I cant comment as to the length but apparently it is 202cm long and is suitable for people up to 185cm. Specs say its 77cm wide at the shoulders and 51cm at the feet – I wear a size 48 jacket and find its snug but there is room in the shoulder area, and you can customise to a longer bag.

Its very expensive… and its expensive before import tax… and its probably not worth it given that you can buy a similar rated bag that weighs 400g more for half the price (and will be more durable) but thats the same weight as my sea2summit thermo reactor liner and a tyvek outer waterproof shell which together makes this bag about the same size and comfortable at below -7˚C
Thats the point; youre not only getting the light weight warmth but also the pack size which is bit bigger than a 190g bottle of Nescafe coffee. You are in command of your budget, and with the Cumulus down sleeping bags you can buy confidently knowing that theirs is a quality product rated as advertised.

Last point whilst researching I came across Criterion. They went to lengths to tell me how the Quantum 200 was used on a Camino in Namibia. I discovered that Criterion bags used to be made by Cumulus and rebranded in the UK, but apparently not anymore. Even with taxes the lighter despite having much more Down, Cumulus was cheaper than the Criterion which supposedly have cooler comfort rating.
That again is a point of contention Cumulus rate their bag at comfort 2˚C with 300g of 900fp Down whereas a “very similar” bag with 200g of 850fp Down is somehow comfort rated at 0˚C.
This follows with the RAB Mythic Down 180 bag apparently comfort rated to 0˚C with 180g of down and the weight is sub 400g. (according to

So yeah there seems to be some fast and loose with the truth going on when it comes to ratings, and its great to know the Cumulus is out there as a benchmark if you will.

Actual weight 498g inside its stuff sack (advertised 465g without stuff sack)
Rated comfort 2˚C - extreme -4˚C
Compressed dimensions: 23cm long x 12cm wide x 44cm circumference (in actual practice)
Compressed Volume 2.6 litres advertised 3.5L… (and it only takes 4 non rushed minutes to stuff in)


As a follow up addendum - still extremely happy with the bag and still no issues at all.

Spent a night in a river bed in Kruger early July where the temperature at 07:30 was 4.9C on my Garmin Tempe (I know it was colder at 05:00 but I was completely warm in the bag)
Also the recent Snow in Joburg I camped in a friends house with a vague attitude towards draft exclusion indoor temperature was 1C and I slept like a baby!

With the bag alone and a thick foam mattress (2cm) or a thermal self inflating mattress I’d gave no issues with taking the bag to -2 without having any additional layers on just normal PJ’s

I’ve just brought a sleeping bag for my sausage dog and am thinking of buying a couple more bags for my kids - I’ll probably spec Quantum pertext for the outer and today airtastic for the inside it’s mildly heavier but more durable for those thugs!

But one things for sure this bag is incredible