What Is a Sleeping Bag Liner?

A sleeping bag liner is a lightweight fabric sack typically put inside a sleeping bag to give additional comfort and insulation. Sleeping bag liners also help keep the sleeping bag from getting dirty. They can be woven from various materials, including cotton, silk, wool, and synthetic fibers.

Bag liners are available in two primary varieties:

• Sleeping liners in the shape of a mummy are designed to be slipped inside your sleeping bag.
• Travel sheets, or rectangular liners, are made to fit inside a rectangular sleeping bag (including double sleeping bags) or can be used independently.

Why Use a Sleeping Bag Liner?

Bag liners are useful for keeping a backpacker’s sleeping bag clean and odor-free. A clean bag doesn’t need to be washed as often and will serve you longer. Meanwhile, a liner is relatively lightweight and can be laundered more easily and more frequently than a sleeping bag.

Depending on the material, a bag liner can increase your sleeping bag’s temperature rating by 5 to 15 degrees Fahrenheit. An alternative to a full sleeping bag is a rectangular bag liner or lightweight travel sheet, especially in warmer climates.

For travelers, using a rectangular bag liner or travel sheet while you’re on the road will help protect you against bedbugs and other pests that may be hiding in questionable lodgings. It is common practice at hostels and is sometimes even required, and it is also widely used by guests of cut-rate hotels.

Common Sleeping Bag Liner Materials

Silk is a lightweight, compact, and remarkably strong material. It is a good insulator when the temperature is cold, yet it is absorbent and breathable when the weather is warm. Price ranges from reasonable to costly.

Cotton is sturdy, long-lasting, and absorbent; nevertheless, it is neither the lightest nor the most compact. It’s economically priced.

Fleece and microfleece are heavier and warmer (by up to 12°F). The mid and heavyweight forms of fleece are substantial but soft, moisture-wicking, and quick-drying. The price range is moderate.

Specialty synthetics specifically marketed as “moisture-wicking” and “breathable” are actually great for hot, sticky weather. Those who have trouble sleeping will appreciate the added flexibility these sheets provide. Their prices are reasonable, especially considering their durability.

Insulated liners provide an additional 25°F, allowing you to take a lightweight backpack (plus liner) on longer trips. Typically being insulated with hollow-core synthetic fiber, they can dry 50% more quickly than cotton. Cost ranges from mid-priced to expensive.

Be sure to check out our how to store a sleeping bag post to learn how to care for your camping gear properly.

How to Choose the Right Sleeping Bag Liner

When selecting a sleeping bag liner, consider these key factors to ensure you get the most appropriate option for your needs:

Season and Climate: For summer camping or warm weather, choose lightweight, breathable materials like silk or lightweight synthetics. For colder conditions, opt for thermal liners made of fleece or insulated materials.

Weight and Packability: If you’re backpacking, every ounce matters. Silk liners typically offer the best warmth-to-weight ratio, weighing only 4-6 ounces while providing decent insulation. Cotton liners, while comfortable, can weigh 12-16 ounces and take up more pack space.

Shape Compatibility: Ensure your liner matches your sleeping bag shape. Mummy-shaped liners work best with mummy bags, while rectangular liners are more versatile and can be used with rectangular bags or as standalone sheets.

Budget Considerations: Liner prices vary significantly based on material:

• Silk liners: $50-$90
• Synthetic liners: $25-$60
• Cotton liners: $20-$40
• Thermal/insulated liners: $60-$120

Allergies and Sensitivities: If you have sensitive skin or allergies, consider hypoallergenic materials like silk or certain synthetics specifically designed for sensitive skin.

Care and Maintenance of Sleeping Bag Liners

Proper care extends the life of your sleeping bag liner and maintains its performance:

Washing Instructions:

• Silk liners: Hand wash in cold water with mild soap or machine wash on delicate cycle. Hang to dry.
• Cotton liners: Machine wash in warm water. Tumble dry on low heat.
• Synthetic liners: Machine wash in warm water. Most can be tumble dried on low heat.
• Thermal liners: Follow manufacturer’s instructions, as some insulated liners require special care.

Storage Tips:

• Always store your liner clean and completely dry to prevent mildew and odors.
• Avoid long-term compression which can damage some materials, especially insulated liners.
• Store in a breathable cotton or mesh bag rather than in a tightly sealed plastic container.

Repair and Maintenance:

• Small tears in synthetic or silk liners can be repaired with nylon repair tape.
• For larger tears, use a sewing machine with appropriate thread matching your liner material.
• Periodically inspect seams for wear and repair as needed to prevent larger tears.

Extending Lifespan:

• Air dry your liner whenever possible during multi-day trips to prevent moisture buildup.
• Consider using a pillowcase over your pillow even when using a liner to keep the head area cleaner.
• Remove your liner and turn it inside out to dry after each night’s use when possible.

Sleeping Bag Liner Temperature Ratings

Different liner materials provide varying levels of additional warmth to your sleeping system:

Silk Liners: Generally add 5-10°F of warmth to your sleeping bag while being extremely lightweight and packable. They’re ideal for backpackers concerned about weight.

Microfiber Liners: These typically add around 5°F of warmth to your sleeping bag while being budget-friendly and comfortable against the skin.

Polyester Liners: Add approximately 4°F of insulation value to your sleeping bag while offering good moisture-wicking properties.

Thermal/Fleece Liners: The warmest option, with some models claiming to boost your sleeping bag’s temperature rating by up to 14°F, though actual results vary by individual and sleeping bag.

COOLMAX Liners: These specialized liners focus on moisture management rather than warmth, making them perfect for humid conditions where staying dry is the priority.

Creative Uses for Sleeping Bag Liners

Beyond their primary functions, sleeping bag liners offer versatility for different scenarios:

Standalone Sleep Sheet: In warm weather, use just the liner while draping your unzipped sleeping bag over you like a blanket.

Hostel/Travel Protection: When staying in hostels or questionable accommodations, a liner provides a clean barrier between you and potentially unsanitary bedding.

Bug Protection: Some specialized liners like the Sea to Summit Adapter COOLMAX with Insect Shield offer built-in insect repellent properties, ideal for cowboy camping or areas with high insect activity.

DIY Options: For budget-conscious campers, consider making your own liner using:

• A queen-sized sheet folded and sewn
• A lightweight kids’ fleece sleeping bag
• Simple cotton or synthetic fabric with basic sewing skills

Sleeping Bag Liner FAQs

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