How to Choose The Perfect Sleeping Bag

Sleeping bags come with temperature ratings to show what temperatures the bag will keep the average sleeper warm. But sleeping bag temperature ratings can be confusing. The listed temps show the lowest temperatures that a bag will keep the average user warm. You will usually find 2 or 3 temperatures shown on sleeping bags. Ratings are either officially tested and certified (like EN13537) or given and approximate temp rating by the manufacturer.

• Comfort Rating – the temp at which a cold sleeper will feel comfortable.
• Limit rating – the temp at which a warm sleeper will feel comfortable.
• Extreme Rating – the minimum temp at which the bag will keep the user alive (you’ll be cold but survive)

Choose a bag with a rating that’ll handle the conditions you'll be out camping in. There’s usually 2 or 3 temps shown on unisex bags – Comfort Temp (at which women should have a comfortable nights sleep), Lower Limit (at which men should have a comfortable night’s sleep) and Extreme Temp (showing the temperature at which you shouldn’t get hypothermia – no one should plan to use the bag in these temperatures).

Seasons

• Summer bags – comfort rating around 10°C
• 3 season bags – comfort usually around 0 to 5°C
• Winter bags – comfort around -5 to 0°C

A few other points worth noting

• Women generally sleep colder than men and should refer to the Comfort rating temps. Men usually sleep warmer and refer to the limit rating. Take the Sea To Summit Spark Pro Sleeping Bag for example – it has a Limit of -1°C for men or Comfort 3°C for women. Also note that there are now women specific bags with stated temp ratings for women.
• Are you a naturally a warm or cold sleeper? If you’re a cold sleeper choose a bag with a slightly lower rating
• Trips into higher altitudes are often colder and require lower temp ratings.
• *You can also use a good sleeping bag liner to boost the performance and warmth of an existing sleeping bag.
• *Make sure that you have a good, insulated sleeping mat under you to reduce the effects of cold from below.

 

• Rectangular or envelope: They have more legroom and are usually a bit bigger, bulkier and heavier. Great if you need more room for your feet, can often be unzipped and used as a quilt and are ideal for car camping.
• Mummy: A tighter fit with tapered legs and a hood for maximum warmth and heat efficiency, and have a smaller packed size and lower weight. Ideal for outdoor adventures where you have to carry your own gear.
• Semi-rectangular: A compromise between rectangular and mummy shapes, providing more room than a mummy but more warmth than a rectangular bag.
• Quilts: A lightweight, versatile alternative to a sleeping bag, with no zippers and no insulation on the underside, instead relying on an insulated pad to keep you warm from below.
• Length and Width: Choose a sleeping bag that fits your body size. Bags come in different lengths and widths. 

 

Sleeping bags are typically lined with one of two insulation materials - down or synthetic. But what’s the difference between the two?

A down sleeping bag is filled with fine soft down duck or goose feathers. Down provides excellent insulation due to its ability to trap air, which retains heat to keep users warm. A synthetic sleeping bag uses man-made fibers, such as polyester, which mimic the insulating properties of down.  

Both make great sleeping bags and are widely used. But they are different and have their own pros and cons.  

	DOWN	SYNTHETIC
Cost	More expensive	More affordable
Insulation	Fine duck or goose feathers	Man made fibres
Weight	Lighter weight	Heavier weight
Warmth	Superior warmth	Heavier weight required to achieve same warmth
Compressibility	Highly compressible, packs down small	Less compressible, bulkier when packed
Performance when wet	Loses loft and insulation when wet, slower to dry.	Retains insulation when wet, dries faster
Durability	Long lasting with proper care	Durable
Care	Requires special care, gentle washing	Easier to clean, hardier and often machine-washable
Comfort	Very soft and comfortable	Comfortable but less luxurious than down
Environmental impact	Duck and goose down – make sure it’s ethically sourced (RDS certified)	Polyester is made from petrochemicals (some use recycled materials)

 

So which one is best for you?

Choose a down bag if you need an ultralight, highly compressible bag with an excellent warmth-to-weight ratio and can afford the higher cost and maintenance requirements. Great for cold dry climates and ultralight adventure activities where low weight and packability are key.

Choose a synthetic bag if you prioritize greater moisture resistance, are okay with a bit more weight and bulk and appreciate the lower cost. Great for over-landing, car camping and activities where you don’t have to carry things long distances.  

 

• Carrying all your gear? Prioritize weight and packability. Choose a mummy or semi-rectangular shape for better warmth and efficiency.
• Car Camping? Comfort and space are more important than weight. Rectangular bags are often a great choice.
• Off on an Alpine adventure? Focus on warmth and durability. Choose a bag with a lower temperature ratings and high-quality insulation.

A couple of other things to think about:

• Insulated sleeping mats: Make sure you have a good sleeping mat working in unison with a good sleeping bag to get the best results. A good, insulated sleeping mat provides crucial insulation from the cold ground, improving your warmth and comfort.
• Sleeping bag liners: Using a sleeping bag liner can add extra warmth to your sleeping bag, keeps it clean, and extends its lifespan. It also enhances comfort, is lightweight, and can be used alone in warm weather or as an additional layer in colder conditions.