PHD Alpine Half Down Sleeping Bag Review

When I was planning my trip to Georgia I knew that I wanted to camp. But, because I’d be running with all my kit on my back, I needed to find a sleeping bag that would be warm enough for the high mountains without adding bulk or too much weight.  PHD’s range of half down bags, designed to be paired with an insulated jacket to make an ultralightweight sleeping system, sounded like the perfect solution. 

Unfortunately, thunderstorms and a bout of food poisoning lead to the bag not being used on that trip. Needless to say though, the PHD Alpine Half Bag has been put to good use since. In fact, it’s now my go-to sleeping bag for overnight adventures. The bag itself is extremely lightweight, almost to the point of feeling fragile, but has kept me warm 3000m up a mountain in the alps, and on numerous trips around the UK without sustaining any damage.

 Packing my entire sleeping system into a 7l dry sack fills me with joy every time. When packed into its stuff sack, the bag is 10x18cm, (noticeably smaller than a portable camping pillow) and, even paired with my down jacket, it’s smaller than my full down sleeping bag. Incredibly, the whole thing only weighs 250g.

Aside from granting me the opportunity to brag about how small a bag I can take camping, it also means I can stick it in my bag for cold climbs in the winter without thinking twice about weight. It’s always useful to have it there, in case I need an emergency bivvy, or just if I want to keep my legs warm while resting.

In use, paired with a decent down jacket, some thermals and a bivvy bag, the Alpine Half Bag keeps me comfortable down to just below freezing (PHD claims down to -10 but from my experience, you would definitely need some serious extra insulation for that to be anywhere near comfortable).

Despite the advantages, it’s not perfect. Sleeping in a jacket is less cosy than a full size down bag and, without a bivvy on top, it can get a bit breezy in the toe box. Overall though, the pros far outweigh the cons.

I’d definitely recommend a decent half bag to anyone looking to cut down the weight and size of their sleeping kit. It’d be particularly useful for bikepackers, alpine mountaineers and trail runners!