10 Best Sleeping Bag Liners 2025 in the United States

The Sea to Summit Reactor Sleeping Bag Liner is a solid choice for campers and hikers looking to add extra warmth and hygiene to their sleeping arrangements. Made from synthetic Thermolite Pro fabric, it is designed to insulate well and reflect body heat, making it suitable for cold conditions down to 25 degrees Fahrenheit below your comfort range. This feature makes it versatile for all-season use. The drawcord footbox is a thoughtful addition, providing customizable comfort and compatibility with select Sea to Summit sleeping bags, enhancing its usability.

The liner's HeiQ Fresh odor control technology is another plus, ensuring it remains fresh even after extended periods of use. The product's dimensions (78 x 31.5 inches) make it spacious enough for most adults, and its mummy shape offers a snug fit without being restrictive thanks to the stretchy knitted fabric. Weighing just 0.81 pounds, it is lightweight and extremely compact, making it easy to carry and pack for outdoor adventures.

Maintenance is straightforward, although the synthetic material might not be as breathable as natural fabrics. Some users might find the price slightly high compared to simpler liners, but the added warmth, comfort, and durability potentially justify the extra cost. Given its features, it is best suited for those who frequently camp in cooler temperatures and prioritize both warmth and hygiene in their sleeping setup.

The Friendly Swede Sleeping Bag Liner is made of microfiber, providing a cotton-soft feel while being breathable. This liner is designed to add up to 10°F of warmth to your sleeping bag, making it suitable for cold weather. It is generously sized at 41 inches in width and 86 inches in length, including a pillow pocket, which should be ample space for most adults. Weighing in at 500 grams or 17.6 ounces, it is relatively lightweight but may not be the best choice for those seeking ultralight packing options.

For those needing a balance between comfort and portability, it is a good fit. The liner is machine-washable, adding to its ease of care, which is a significant plus for camping trips where staying clean can be challenging. The full-length zipper allows for easy entry and exit, and the durable construction means it can withstand the rigors of outdoor use. It also plays a crucial role in keeping your sleeping bag clean by acting as a barrier against sweat and bacteria.

One drawback might be that while it’s great for adding warmth, it may be less effective in extremely hot conditions compared to liners made specifically for cooling. The lifetime warranty offered by The Friendly Swede adds a layer of assurance for long-term use, making it an appealing option for regular campers.

The Sea to Summit Reactor Insulated Sleeping Bag Liner is designed to add extra warmth and hygiene to any sleeping bag, making it an excellent choice for camping and hiking enthusiasts. Its material, Thermolite, is known for being lightweight, soft, and comfortable, which makes it a pleasant addition to your sleeping arrangements.

The liner is mummy-shaped with a toe-box, draw cord hood, and includes a stuff sack for easy packing, which is a convenient feature for travelers. It weighs just 14 ounces, so it won't add much bulk to your backpack, and its packed size (6.5 x 4.5 inches) is quite compact.

The liner is designed to add up to 25°F degrees of warmth, which can be a significant boost in colder environments, making it a versatile accessory for varying temperatures. However, one downside is that its size, 83 x 35 inches, might be a bit restrictive for taller or broader individuals. Additionally, while it’s easy to pack, the Thermolite material may require specific care to maintain its insulation properties over time. The price might be a bit steep for some, considering it's an accessory rather than a primary item. This sleeping bag liner is best suited for campers and hikers looking for added warmth and hygiene without adding much weight to their gear.