Nemo Forte Endless Promise Men’s Synthetic Sleeping Bag review: sustainable slumbers

Nemo is a brand that doesn’t bring anything to market unless it’s an improvement on what’s already out there. In the case of its newest synthetic Forte sleeping bags, it took its original design and gave it a sustainable overhaul, crafting a cozy cocoon of recycled materials that's also 100% recyclable at the end of its life too. The launch officially kicked off the brand’s Endless Promise collection in 2023.

So, keeping in step with the likes of Patagonia and Rab, Nemo has got its eye on the full lifespan of its products. The Forte Endless Promise bags are constructed from a single type of material, which makes it much easier to recycle and goes a long way to keeping waste out of landfills.

I was stoked to test this environmentally friendly, 3-season sleeping bag in the backcountry to see if its performance is as strong as its green credentials.

First Impressions

When I first clocked the Forte in its compressible stuff sack, it was apparent that it wasn’t the most packable sleeping bag in town. If you’re looking for an ultralight, uber-packable sleeping bag, ideal for long, multi-day backcountry expeditions or summer thru hikes, this isn’t the bag for you. However, this is hardly surprising given its modest price point and the fact it features synthetic insulation, rather than down. It weighs 1.64kg / 3lb 10oz, which is on the heavier side of things, and it doesn’t pack down as small as the best in the business. If ultralight kit is your thing, you're set on a Nemo bag and you've got cash to spare, check out the more expensive Nemo Coda.

Nevertheless, once I unclipped the stuff sack and liberated the Forte, I quickly appreciated its quality. The soft polyester inner feels lovely against the skin and clever features, such as the Thermo Gills and pillow pocket, hint at the careful consideration that’s gone into the design.

Recycled, recyclable fabrics

There’s a lot to shout about when it comes to the recycled main fabrics, which are bluesign approved, as well as fully recyclable thanks to their mono-polymer construction. The shell is a 30D ripstop polyester, while the plush lining is a 20D polyester taffeta. Taffeta, usually made from either silk, polyester or nylon, is a shiny, crisply woven fabric often associated with high fashion. Here, it lends comfort to the Forte’s its luxurious inner sanctum, your soft cocoon for happy slumbers.

In between these layers is the post-consumer recycled synthetic fill, which maintains its loft beautifully and retains its thermal qualities when wet – an oft-stated advantage of synthetic insulation over down.

Thoughtful features

One of the Forte's most striking features is its profile. Rather than the traditional mummy form, it has what Nemo call a 'spoon' shape. I don’t know what Nemo’s marketing team have been eating, but it doesn’t look that much like a spoon to me. I’d have called it an hourglass shape: it’s widest at the shoulders, tapers a bit in the middle, widens again around the hips, before tapering significantly at the footbox. This shape provides an unrestricted sleep, allowing side sleepers to shuffle around in comfort, with more space at both the shoulders and knees.

There’s plenty going on around the head, with a cinchable hood, draft collar and a compartment for a camping pillow. When the temperatures plummet, the draft collar can be tucked in to provide a shield against the cold, while the hood can be brought in tight.

Speaking of cold, the bag is suited to 3-season use, with a Comfort rating of -1°C / 30°F. I camped in temperatures of around 5°C / 41°F and found the bag to be nicely warming. There's no doubt that it could have the potential to be overly warm in really hot conditions, which is why Nemo employs two Thermo Gills on the front towards the top. These are zippered openings that reveal a thin panel of the inner fabric that allows radiated body heat from inside and ambient air from outside to bypass the insulating layer, allowing the sleeping bag to breathe and cooling the wearer down.

Down the left side is the almost full-length zipper with anti-snag guard, which can be opened from both the interior and the exterior. The footbox has a couple of loops for easy hanging when storing, airing or when you need to wash your sleeping bag and dry it afterwards.

When it’s time to pack it away, there’s a stuff sack armed with compressions straps that can be tightened for transportation. However, don't forget that the best way to store a sleeping bag is to hang it up, if you have the space.

In the field

I used the Forte during summer car camping trips and for a backpacking expedition in the English Lake District, where I was able to fully test its 3-season credentials during a chilly summit camp. I’m still alive, so it must have done something right.

In fact, it did more than that. I found sleeping in the Forte a very pleasant experience throughout. Comfort is what this bag does best and its spoon shape means that it’s less restrictive than many other bags. I never got that awful, claustrophobic feeling you sometimes get when the sleeping bag says “no”, as you try to turn in the night and you have to wriggle a bit to free yourself back up from fabric that has coiled around your legs like a polyester anaconda.

During warm summer nights at sea level, the Thermo Gills allowed me to cool things down and I really appreciated their presence. They were then fully closed up during my mountain camps. Meanwhile the ability to cinch things in tight and utilize the draft collar allowed me to lock precious heat in during what would have otherwise been quite a brisk wild camp.

So, there’s nothing wrong with wild camping with the Forte, though it does take up quite a bit of space in a backpack and, as mentioned, there are lighter alternatives out there. It's definitely something to consider if you're intending to take on a load of elevation gain to access a hard-won, remote wild camping spot.

To begin with, I was unable to fit my Nemo Fillo pillow into the pillow pocket! However, any frustration was short lived, as I realised the answer was to insert the pillow pre-inflation and then blow it up once in situ. The tight gap that had stopped me inserting the inflated pillow to begin with was now the same one keeping it in place. Ideal! I approve of this feature, as it stops the pillow moving around or slipping out from under my head. This had been a qualm I’d had with the otherwise superb Nemo Tensor Extreme Conditions Ultralight Sleeping Pad, as the pillow would slide along its smooth surface like a greased eel.

The stuff sack is well designed. On the bottom is a large fabric loop for carrying or for pulling in the opposite direction liberating the bag from the sack. The compression straps are easy to pull tight or loosen, while getting the bag back in the sack isn’t a struggle.