{"id":159266,"date":"2020-06-07T12:00:48","date_gmt":"2020-06-07T19:00:48","guid":{"rendered":"https:\/\/www.rei.com\/blog\/?p=159266"},"modified":"2021-07-06T12:49:53","modified_gmt":"2021-07-06T19:49:53","slug":"material-science-sleep-systems","status":"publish","type":"post","link":"https:\/\/www.rei.com\/blog\/camp\/material-science-sleep-systems","title":{"rendered":"Material Science: Everything You Need to Know About Sleep Systems"},"content":{"rendered":"

A version of this story appeared in the summer 2020 issue of\u00a0Uncommon Path<\/a>.\u00a0<\/em><\/p>\n

<\/h2>\n

The Sleeping Bag<\/h2>\n

Many bags<\/a> you\u2019ll find at REI come with two temperature ratings: one for comfort and one for a lower limit. The labeling looks like this.<\/p>\n

\"sleeping

Of course, know thyself. If you run a bit colder, consider a bag\u2019s comfort rating your personal lower limit.<\/p><\/div>\n

Comfort Rating (T-Comfort)<\/strong>: If the ambient air temp outside is this number or higher, a cold sleeper should be comfortable (assuming you\u2019ve paired your bag with the right pad; see right).<\/p>\n

Lower-Limit Rating (T-Limit)<\/strong>: If it\u2019s colder than this lower temperature, even a warm sleeper may be chilled.<\/p>\n

 <\/p>\n

The Sleeping Pad<\/h2>\n

When you crawl into your sleeping bag, you compress the insulation. That, combined with the cold ground, is a recipe for a shivery night. So, yes, your pad cushions you from rocks and roots, but its most important job is to help you retain your body heat, which is measured by its R-value.<\/p>\n

R-Value<\/strong>: This value measures your pad\u2019s thermal resistance, or its ability to prevent heat loss. Most camping pads live somewhere between 2 and 6, with the higher numbers being more insulating.<\/p>\n

 <\/p>\n

The Sleep System<\/h2>\n

Your bag and your pad create your sleep system. Seems simple enough, but neither actually works as advertised unless paired properly. Our sleeping bags are all tested on a surface that\u2019s about the equivalent of an R-value of 5.4. A sleeping pad with an R-value of 5.4 is considerably warm and often reserved for winter camping. Chances are, you\u2019re not using a pad as warm for three-season camping\u2014which means your bag\u2019s temperature ratings won\u2019t be accurate. Use this chart to pick the right bag and pad for you.<\/p>\n

\"sleep<\/p>\n

REI Co-op member Bilen Beck (below left) sleeps cold, so she\u2019d love the electric-blanket-like warmth of this sleep system: Her stacked pads give her an R-value of 6.2, meaning she\u2019ll feel cozy at her pad\u2019s comfort rating.<\/p>\n

REI Co-op member Samuel McDonald (below right) is a warm sleeper. The 4.2 R-value of his pad should make his quilt comfortable just above 30\u00b0F. But if he gets too hot, he can always stick a leg out or fold the quilt over like a comforter.<\/p>\n

\"sleep<\/p>\n

Bilen\u2019s Sleep System<\/h4>\n