There’s plenty of warm wiggle room in Nemo’s Jam 30 sleeping bag

With ample 800-fill down and a generous spoon-shaped cut, the Jam 30 sleeping bag from Nemo brings bed-like comfort to backcountry sleeping.

The sleeping bag market is very competitive with offerings from almost every major outdoor manufacturer, along with a slew of small cottage companies as well. Nemo falls into the latter category and is known for its well-thought-out designs. Nemo’s latest sleeping bag — the Jam series for women and the Riff series for men — upholds this tradition by combining not one but two cutting edge designs into a single bag. These are the brand’s first sleeping bags to combine Nemo’s patented Thermo Gills vents, which help reduce heat, and the company’s unique spoon-shaped cut, which provides extra elbow and knee room.

These features certainly sound great on paper, but how do they pan out in the backcountry? To give the Jam 30 a proper run for its money, we packed the thing along on a recent backpacking and hammock camping trip to find out.

Thermo Gills work when you know how to use them

The Jam 30 incorporates Nemo’s innovative Thermo Gills technology which includes two small slits in the front of the bag. These slits are covered with fabric which allows warm air inside the bag to escape while preventing cold air from seeping in via a draft. The concept is elegantly simple — when it gets too hot, users simply open one of the slits to vent heat.

During our testing, we found the Thermo Gills to be useful in venting heat but very subtle in their effect. The Thermo Gills work best over a longer period of time and aren’t necessarily useful for immediate relief from the heat — unfortunately, they don’t do that well in cooling off quickly. The best strategy for overheating is to unzip the bag for a short time to quickly drain off the heat and then zip up the bag with the Thermo Gills open. Thankfully, we didn’t need to worry about it getting too cold after doing this as the Gills worked wonders in blocking cold air from entering the bag.

We did find that the openings work best when utilized as a preventative measure. In other words, when the forecast calls for a particularly warm night, we opened the vents shortly before going to sleep to allow any trapped heat to seep out gradually.

The Jam wants to spoon

Rather than adopt a traditional mummy cut, Nemo opted to do things differently with the Jam. The company developed and tested a unique spoon shape which provides extra room in the elbows and knees, including it in several of its latest sleeping bags, including the Jam 30.

This spoon cut is perfect for side sleepers, allowing them to move freely without getting tangled up in the bag — a common experience with slimmer mummy cut bags. This comfort added some extra weight to the sleeping bag but after spending a few days with it, we found this increase in weight to be well worth it.

A three-season champ

Nemo rated the Jam 30 to 30-degrees, making it an ideal warm weather bag for cold climates and perfect as a three-season bag in warmer climates. We tested the bag in the early spring when overnight temperatures hovered in the mid-30s and found the bag to meet its advertised ratings. With a lightweight Thermarest sleeping pad underneath us, we stayed toasty warm from head to foot in just a base layer of clothing. On warmer nights, we were also able to use the two-way zippers to crack open the bottom half of the bag to let in a bit of cold air. Another added benefit is the 800 Fill Power down that has Nikwax water repellency, allowing the bag to keep its warmth even when the weather gets wet.

The unexpected standout feature of the Nemo 30 was the blanket fold. On paper, the Blanket Fold seemed like a gimmick but in real-life usage, it proved to be indispensable in keeping us warm. When temperatures dropped into the 30s, we used the drawstring to pull the hood tight around our face and neck. Then, we tucked the Blanket Fold into the sleeping bag and stuffed it into the gaps around our neck and shoulders. Once we plugged these drafts, our night outside was as comfortable as it was warm.

When temperatures climbed into the upper 40s and higher, we simply took the Blanket Fold out and let it rest beside us — a level of versatility that’s welcome in a high-quality sleeping bag.

Middle of the pack weight class

The Jam 30 weighs 2 pounds 3 ounces (995g) and can be packed down to 7 liters, placing it squarely in the mid-range for a single person sleeping bag. There are bags like Marmot’s Phase 30 which offers the same temperature range as the Jam 30 but weighs only 1lbs 1.6 ounces (500g) while packing down to a mere 3 liters. It’s a trade-off, though, as Marmot’s model sheds weight by using 10D nylon instead of the more durable 20D nylon used in the Jam 30. The Phase 30 also doesn’t feature hydrophobic down like the Jam 30, which provides excellent water repellency.

Warranty information

Nemo Equipment offers a lifetime warranty on all gear for defects in product manufacturing. This warranty is granted to the original purchaser with a proof of purchase from a Nemo authorized dealer. Additionally, Nemo does not warranty products against normal wear and tear, unauthorized modifications or alterations, improper use, improper maintenance, misuse or neglect, or if the product is used for a purpose for which it is not intended.

Conclusion

Nemo is best known for its roomy spoon-shaped sleeping bags and Thermo Gills feature, each of which provide maximum comfort in the backcountry. The new Jam 30 sleeping bag delivers both of these innovative designs in a single bag — a combination which makes this model comfortable in a wide range of temperatures while accommodating a variety of sleeping positions.

Highs

• Even distribution of the 800-fill down keeps you warm
• Blanket Fold creates a snug fit at the neck that blocks drafts
• Integrated pillow pocket lets you make a pillow out of an extra jacket
• Spoon cut makes it comfortable to sleep on your side
• Two-way zipper easily vents the bottom of the bag

Lows

• Stash pocket fits only small items; can’t accommodate a smartphone like an iPhone 7 Plus
• Zippers on the stash pocket and Thermo Gills are hard to find in the dark