Exped Waterbloc Pro -15° sleeping bag review: warm and waterproof enough you can even bivy in it

The Exped Waterbloc Pro -15° is the lightest weatherproof down sleeping bag on the market

Exped Waterbloc Pro -15° sleeping bag
(Image: © Emily Woodhouse)

Advnture Verdict

A lightweight and very warm sleeping bag, ideal for nights bivying out in winter, which is as waterproof as possible without turning it into an actual bivy sack.


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    Water-repellent shell

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    Waterproof stuff sack

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    3D foot box

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    Storm flap on zip


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Exped Waterbloc Pro -15°: first impressions

The Exped Waterbloc Pro is a four-season winter sleeping bag designed with bivying in mind. The medium size bag (which I tested) has 800 fill down, making it very soft and warm, with a Pertex outer shell that effectively repels the weather.


• List price: $749.95 (US) / £640 (UK)
• Shape: Mummy
• Weight: Small: 1,225g / 43oz ; Medium: 1,280g / 45oz; Long: 1,340g / 47oz
• Length: Small: 190cm / 75in; Medium: 205cm / 81in; Long: 220cm / 87in
• Pack size: Small: 27cm x 17cm x 15cm / 10.6in x 6.7in x 6in ; Medium: 27cm x 17cm x 16cm / 10.6in x 6.7in x 6.3in ; Long: 27cm x 17cm x 17cm / 10.6in x 6.7in x 6.7in
• Fabric:
Water-repellent Pertex QuantumPro shell
• Fill: 800+ in3/oz goose down
• Comfort: -6°C / 21°F
• Limit: -13°C / 8.6°F

Although it is sold as “waterproof” in some marketing material there is also a disclaimer that you obviously can’t lie out in a downpour and expect to stay dry. The outer shell is Pertex after all, not a crunchy waterproof jacket fabric. Not that you’d want a completely waterproof sleeping bag anyway – that’s what bivy sacks are for and a zero breathability sleeping bag sounds like a sticky night’s sleep.

That said, Exped have gone out of their way to make this sleeping bag as water resistant as possible: the entire outer shell has barely any seams, the zip has a Pertex storm flap and the 20D Pertex Quantum Pro has a 1,000mm water column. It’s designed for sleeping in open air or under a tarp – or perhaps in a hooped bivy that gets a bit damp overnight.

You can snuggle up in your down with peace of mind that – come condensation or light rain – you won’t wake up in a soggy mess of clumped down and broken dreams. The one thing they’ve avoided is any treatment of the down: “All Exped refrains from using environmentally damaging hydrophobic down treatments.”

Exped Waterbloc Pro -15° sleeping bag

The zip has a Pertex storm flap  (Image credit: Emily Woodhouse)

Exped Waterbloc Pro -15°: in the field

In terms of comfort, this is a very lofty sleeping bag with lots of attention paid to keeping unwanted cold air out. There are draw cords around the hood and neckline, plus an extra down collar around the neck. Behind the zip is a similar draft excluder to prevent that annoying cold line, and the foot box has been specially engineered to stop cold spots. 

A lot of attention has gone into this: there are 11 separate chambers, individually filled with down – and you can really tell. It’s the warmest my feet have ever been in a sleeping bag. In fact, I was surprised how well it warmed up and how little air gap I had, especially considering I was testing a size bigger than I really ought to have for my height.

Exped Waterbloc Pro -15° sleeping bag

The foot box has been specially engineered to prevent cold spots (Image credit: Emily Woodhouse)

The one question is on the actual temperature ratings. It’s called a -15°C (5°F) sleeping bag but the comfort, limit and extreme temperatures listed on the website are different (warmer) to those printed inside the bag. And surprisingly none of those numbers are -15°C (5°F). The sleeping bag comes with a dry bag for packing and a roomy mesh bag for storage at home.

Emily Woodhouse

An adventure writer based on Dartmoor, England, Emily is an active member of Mountain Rescue and a summer Mountain Leader, but loves all things adventure – before her third birthday she had lived on three continents. Founder of Intrepid magazine, she works to help break stereotypes about women in the outdoors. Her expeditions have included walking all Dartmoor’s 119 tors in a single two-week outing, cycling to Switzerland and back, and riding the Rhine from source to sea.