Exped Ultra 0 sleeping bag | Tested and reviewed

We put the premium Exped Ultra 0 sleeping bag to the test. Is this the ultimate summer sleeping bag?

Exped Ultra 0 with zip open

by Chris Williams |
Updated on

Anyone familiar with the Swiss outdoor brand Exped will know it’s all about technical gear – primarily packs, tents, and sleeping bags.

The Exped Ultra series sleeping bags aim to be among the very best sleeping bags you can buy, with five versions catering to temperatures of 10°C right down to about -20°C. From warmest in descending order, the Ultra 0 sits at number four in the series, intended for nights in the low positives.

The Ultra 0 is incredibly light and uses some of the finest materials you’ll find on a modern sleeping bag, so let’s have a look at it in detail and you can get an understanding of how it performs from our field testing.


  • Sustainable
  • Super lightweight and compact
  • Five sizes available
  • Impressive warmth-to-weight ratio


  • No hydrophobic down treatment

Temperature ratings

The Ultra 0 has a comfort temperature rating of 7°C and a comfort limit of 2°C. Temperature ratings are intended as guides only, as people have varying levels of susceptibility to cold. But nevertheless, the Ultra 0 is certainly a sleeping bag for us in summer and the milder nights of spring and autumn.

Insulation type, fill power, and fill weight

Exped Ultra 0

In order to achieve a very high warmth-to-weight ratio, the Ultra series sleeping bags use 850-fill power European goose down – RDS certified of course. This is very high quality down, which lofts very well and makes the sleeping bag feel very fluffy. Many competitors use 600 to 750-fill down.

The long version we tested uses 295g of down, but this fill weight varies from 225g up to 370g depending on the size you go for. The price also varies depending on the size, with RRPs hovering around £400, give or take about £50. That's a lot, so we had high expectations.

It is worth noting that the down used in the Ultra 0 doesn’t have a hydrophobic treatment that others such as Rab’s Neutrino series sleeping bags have. This is a feature that has become common on many high end sleeping bags. In our experience, it’s not a massive plus point – a hydrophobic treatment isn’t a complete remedy to down’s susceptibility to damp. It helps, no question, but isn’t a deal breaker for us.

Pack size and weight

Exped Ultra 0 in stuff sack next to a water bottle for scale

This is an area where the high quality, lightweight materials used on the Ultra 0 pay healthy dividends. Depending on size, the Ultra 0 weighs from 510g up to 690g. That is a very impressive achievement for a 2.5-season sleeping bag.

What’s similarly impressive, if not more so, is the pack size. The long size we tested packs down to a mere 30 x 17cm. With such a low weight a pack size, we found the Ultra 0 can easily fit into smaller overnight backpacks and will be of serious interest to fans of ultralight backpacking, bikepacking, and fastpacking.

Materials and sustainability

Exped Ultra 0 zip dome

Exped has made sure the materials used to make the Ultra 0 are not just super lightweight, but more sustainable too.

The 10D Pertex Quantum shell material is fully recycled and bluesign-approved, while using a plant-based, PFC-free water repellent treatment. The lining is 15D nylon – it isn’t recycled but is Oeko-Tex 100 certified. Exped has also used zips made from recycled bottles.

To help improve its eco credentials further, Exped offsets the emissions of the manufacturing of the Ultra 0 (the procurement of raw materials through to production, transportation, usage, disposal and recycling).

We certainly think Exped is more proactive around sustainability than many competitors. The shell and lining materials do feel a bit delicate – so in order to get long term durability from this pricey sleeping bag, you’re going to have to be careful with it. But, if there is a rip or broken zip, there are retailers and specialists that can quite easily repair sleeping bags.

Size and shape

Exped Ultra 0 displayed on grass

To maixmise thermal efficiency, the Ultra 0 is a tapered mummy shaped sleeping bag. Having used countless sleeping bags of this shape over the years, we’re quite used to it and find them snug. But understandably, some people do find them restrictive.

On the plus side, the Ultra 0 comes in five sizes: small, medium, medium wide, long, and long wide. That allows the Ultra 0 to cater to a wider range of body shapes than many rivals that often come in just two sizes.

The long size we tested is designed for people up to 195cm tall. We found it’s relatively narrow across the shoulders at 151cm circumference but there are the wide versions for those that need the extra girth. However, at the other end, we liked the 3D triangle footbox, which gives a nice amount of space without developing cold spots.


Exped Ultra 0 hood and draft collar

The Ultra 0 features everything you’d expect from a top end sleeping bag that is all about thermal efficiency. Its hood is adjustable to cinch in close around the head, and there is an effective draft collar too.

The three-quarter zip is two-way and we found doesn’t snag. Some sleeping bags give you the option of a left or right sided zip but the Ultra series all have zippers on the left side only. Inside, there is also a small security pocket.

Exped Ultra 0 security pocket

The baffles are shaped in a so-called I-beam construction, which Exped says allow the down to be ‘shifted as needed’ so you can adapt it to the temperature and sleeping mat. The shell and lining materials are use what’s called a proportional differential cut, meaning the lining is cut narrower than the shell to allow the down to loft as well as it can.

Long story short, we found that the down lofts very well, and while we were suspicious that the I-beam baffles might allow the down to simply clump in one place, we didn’t have that issue.

The compression sack is a roll top, like a dry bag. It's fine but one with compression straps would make it easier to pack the Ultra 0 down as much as possible. Exped also supplies the Ultra 0 with a large mesh storage bag to allow the down to loft when in storage at home.

Exped Ultra 0 two way zip


Put simply: if you’re after one of the very lightest, compressible, and sustainable summer sleeping bags on the market and are willing to spend a premium to get it, the Ultra 0 is for you.

We like Exped’s attention to detail, sustainability efforts, and the five sizes available here. The Ultra 0 feels somewhat delicate because of its super lightweight shell and lining, but if used with care, it should still last as long as you need it to.

How we tested

Chris Williams hiking in Lake District wearing Artilect Divide Fusion Stretch Jacket

The Exped Ultra 0 was tested by Chris Williams (above), one of our staff writers and gear testers, over the course of nearly a year.

Chris is a journalist and hiking fanatic from New Zealand, and has been with us since 2021.

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