Sleeping Bag Choice

Sleeping bags are a relatively big-ticket item in your personal outdoor equipment cache and something that may last you many years - I’m on to only my third bag in over 40 years of moderate use and my first one is still usable, albeit patched with duct tape! So, it is a choice you want to make wisely and there’s quite a bit to choose from: mummy or rectangular shape, short or long zip, down or synthetic fill, sewn through or baffled construction, 2, 3 or 4 season, and then there is confusing fill power and weight, temperature ratings and a wide choice of brands. If you are loyal to a brand, that solves the later dilemma, but what of the other choices? 

Temperature Ratings Explained

Comfort Rating - Indicates the temperature at which cold sleepers/women typically might feel comfortable.

Lower Limit Rating - Indicates the temperature at which warm sleepers/men typically might still feel comfortable.

Temperature Ratings are measured in lab simulations of how a sleeping bag should be used, with a sleeping pad placed under the bag and the occupant wearing base layers. This protocol doesn't account for variations in people's sleeping pad and clothing, body types (warm and cold sleepers), weather conditions, the food people eat and more. So, consider them indicative only. Comparing temperature ratings within a single brand is usually more meaningful than comparing across brands, since the variables used in testing can vary.

Down vs synthetic - the trade-offs

Down gives you warmth for weight like nothing else. It’s super compressible, long-lasting, and packs down small - ideal when you’re trying to shave grams and space. It does cost more, requires more care, and some people prefer to avoid animal products, which is where synthetic comes in. Synthetic fill is cheaper, hypoallergenic, and a solid choice although it’ll be bulkier for the same warmth and less durable.

Down but not out - are down sleeping bags suitable for wet conditions?

Short answer: yes. Long answer: still yes, if you know what you're doing.

The idea that down is “the worst” insulation in damp conditions? Seems to be a myth that won’t die. Never mind that ducks and geese spend their lives floating on cold lakes and waddling through snow and sleeping rough. Apparently, the same feathers that keep them warm and dry work after all with no special coatings. Go figure. 

Don’t believe me? Someone's already done the work, knows the science, has real backcountry mileage, tested it, filmed it, and posted the results on YouTube. Does it look like a pleasant experience? Maybe not. Warm? Yes. At this point I bow out – here’s the link. Enjoy!

Where your down comes from

If you're considering a down-filled sleeping bag, it’s worth asking where the feathers came from. Not all down is created equal, some is a grim by-product of live-plucking and force-feeding.

The good news is many reputable outdoor brands now use ethically sourced down certified by third-party standards. Look for Responsible Down Standard (RDS) or Global Traceable Down Standard (Global TDS) certified bags. Obviously, synthetic (plastic!) fill dodges the animal ethics question entirely.

Which sleeping bags do hiking guides use? 

Looking at my bag choice over the years, they have all been down filled, and mummy shaped with a hood giving optimum warmth for their weight. They have had a short, long and now back to a short zip. In a 3 or 4 season bag, a long zip gives greater versatility for summer and indoor use for the ventilation it offers and being able to open it out into a quilt, although it does add grams. There has been a trend toward lighter weight and more compressible bags in my choice. Some of this has been attributable to advances in materials but mostly to my desire to be more minimalist.

As a guide there is a bit of stuff that I have to carry and can’t skimp on, so it made sense to me to reduce the weight and packed size of my personal gear including my sleeping bag to keep my pack weight and volume manageable. For overnight hikes to the locations we visit in spring through autumn I have found my latest choice up to the task.  While I have come to consider my sleeping bag as something to compliment my clothing system to keep me warm, I have rarely needed to wear more than a thermal layer, socks and a beanie. I am a warm sleeper though, add a silk liner, and another trick is that I don’t go to bed hungry!

So, to my choice of a Sea to Summit Spark SP2 which weighs under 500g and has a truly tiny packed size. It has a temperature rating described as 4°C comfort rating woman / -2°C lower comfort rating for men, which you should find adequate for our trips. I find the mummy shape quite narrow and constricting and would prefer something wider in the foot and a long zip but at the expense of added weight. So many trade-offs!

For comparison, we have the Macpac Escapade 350 for hire with the same temperature rating. It has a roomier shape and a full length side zip and foot zip that weighs just under 1kg and has a proportional packed size.

Still have unanswered questions?

Here are a few of many “artisanal” brands that make some of the best technical bags on the market. Peruse their websites, fall down a few rabbit holes, and you’ll come out the other side either enlightened or totally overwhelmed. Either way, I’m sure you’ll learn something from the experts.

·      Western Mountaineering – USA

·      Feathered Friends – USA

·      Valandre – France

·      Mountain Equipment – UK

·      PHD – UK

Words by Mo (and Louis)