Mountain Equipment Soul 15/25 Synthetic Sleeping Bag

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Recycled, refined and ready for cold, the Soul 15/25 blends technical warmth with thoughtful design.

Nemo says: 

Essential Comfort for Exploration.

NEMO’s newest sleeping bag silhouette is now offered with aerospace-grade, recycled synthetic insulation for ultralight adventures in any climate. Inspired by the traditional tapered mummy bag, Soul has a sleek, streamlined shape that shaves excess material and weight wherever possible but still sneaks in plenty of comfort features. A mono-polymer design, Soul also meets our Endless Promise standard and can be fully recycled at the end of its life — just send it back to NEMO, and we’ll handle the rest.

Soul’s single, asymmetrical front zip integrates with our innovative Headwall™ internal draft guard to provide 360-degree protection. A plush, insulated collar, Headwall wraps around the back of the neck and cozily overlaps itself in front to efficiently block cold air while creating a uniquely comfortable experience. Balancing the front zipper is a single Thermo Gill™ vent, enabling fine-tuned temperature control. With both internal and external zippers, the Thermo Gill incrementally releases body heat without direct exposure to the cold, extending the usable temperature range of the bag. For additional instant ventilation (or simply to let your feet poke out), the footbox also features a zippered opening. Highlighting the clean design are strategically placed vertical and horizontal baffles to optimize warmth and comfort while preventing migration of the Zerofiber™ 800 synthetic insulation.

Highlighting the clean design are strategically placed vertical and horizontal baffles to optimize warmth and comfort while preventing migration of the aerospace-grade, 100% recycled synthetic insulation. Manufactured from a single type of material, this sleeping bag is 100% recyclable when it can no longer be repaired or resold — just send it back to NEMO, and we’ll handle the rest.

A unisex bag, Soul calls out both the Limit temperature rating and the Comfort temperature rating in its name. Per industry standards, the Limit rating (the first number referenced in the series) is considered the benchmark for men, while the Comfort rating (the second number referenced in the series) is considered most applicable to women. For a complete explanation of how to interpret these numbers, read our blog here.

Our Verdict

The Nemo Soul 15/25 is a well-considered synthetic bag built for cold conditions without excess bulk. It’s rated to –9 °C (limit), with comfort around –4 °C, and feels reliably warm thanks to its recycled Zerofiber insulation and strategic baffling that limits cold spots. The cut is streamlined yet not restrictive, featuring a roomy interior that accommodates side sleepers and those who find traditional mummy bags constrictive. 

The Thermo Gill vent system works well for fine-tuning airflow, and the zipped footbox vent adds flexibility on warmer nights. The Headwall draft collar wraps softly around the neck and holds heat without being intrusive. Materials are robust but soft, with a waterproof footbox to guard against condensation from tent walls, something I always like to see on a sleeping bag

– Reviewed by Ultralight Outdoor Gear

Features

• Efficient, tapered mummy design cuts excess weight for ultimate packability.
• Apparel-inspired Headwall™ internal draft guard provides 360-degree insulated, plush protection from the cold.
• Updated Thermo Gill™ vent extends the comfort range and creates fine-tuned control with its multistage zipper system.
• NEMO takes full responsibility for all Endless Promise® products, from production to end of life, and designs them for total recyclability to keep out of the landfill.
• Zerofiber™ 800 is made from post-consumer recycled material and is the highest-performing synthetic fill possible — ultralight, water-resistant, and warm when wet.
• Hood and footbox are reinforced with recyclable, waterproof material to prevent tent condensation from soaking into the bag’s fabric.
• Zippered opening at the foot of the bag allows direct access and instant ventilation.
• Streamlined hood cinch hardware is bonded to the material and more integrated into the bags design than traditional dangling designs.
• Protected by the NEMO Lifetime Warranty

Specifications

• Temperature Rating: 15F / -9C
• ISO Comfort: 27F / -3C
• ISO Lower Limit: 16F / -9C
• ISO Extreme Limit: -18F / -28C
• Bag Shape: Mummy

Regular

• Weight: 1312g
• Fits to: 6′ (183 cm)
• Paked Size: 14.0 x 9.0 in dia / 35.5 x 23 cm dia
• Shoulder Circumference: 63 in / 160 cm
• Hip Circumference: 55 in / 140 cm
• Knee Circumference: 46 in / 117 cm

Long

• Weight: 1446g
• Fits to: 6’6″ (198 cm)
• Paked Size: 14.0 x 9.0 in dia / 35.5 x 23 cm dia
• Shoulder Circumference: 67 in / 170 cm
• Hip Circumference: 59 in / 150 cm
• Knee Circumference: 50 in / 127 cm

Material & Construction

• Shell Material: 100% Recycled Polyester Ripstop w/ C0 DWR
• Lining Material: 100% Recycled Polyester Ripstop w/ C0 DWR
• Footbox Material: Waterproof/breathable w/ C0 DWR
• Insulation: Zerofiber™ 800 PCR

Help & advice:

• The Ultimate Guide to Lightweight Sleeping Bags
• Time-Saver Guide to Choosing a Sleeping Bag
• NEMO Equipment – Meet the Team
• About Nemo
• Nemo Video Resources
• Recycled Content in Outdoor Gear
• Sleeping Bag Shapes & Sizes
• Down Quality
• All About Down
• Hydrophobic Down
• Responsible Down Standard