Mattress R-value and EN sleeping bag ratings

Did you know that your EN rated sleeping bag requires a mattress with an "R-value" of 5 or greater in order to meet its stated temperature performance?  Most people do not realize that the mattress used in the testing fixture for the EN test has an R value of 5.

But MOST mattresses sold today, especially the newer, lighter air mattresses, fail to meet that standard.

The result is that most sleeping bags with a rating of 5º to 30ºF (-15º to -1ºC) are "mis-paired" with mattresses of R-value of 3 or less.  And its a recipe for some cold nights in the backcountry:

• If you can't sleep comfortably at the "EN Comfort" rating of your sleeping bag, it's likely because of insufficient insulation underneath.  
• If you think you need a winter bag for 3 season use, it's likely because of insufficient insulation underneath.
• If you need a really warm, high loft sleeping bag to pair with your uber-light air mattress so you can stay warm, you may find its lighter to get a better mattress and a lighter bag.

Mattresses are commonly "mis-rated", with R-value 5 mattresses often marketed as "winter", and R-values of 3 or less marketed as "3-season". These ratings are misleading. While mattresses with less than R-5 can provide sufficient insulation for warmer conditions, if you intend to push your bag to freezing or below, it just makes sense to get a properly matched mattress.  And that means R value 5.

Every mattress we sell at Zenbivy.com meets this standard, and so you can expect full EN rated performance out of any sleep system purchased here.

Don't fall victim to marketing hype.  If you want full temperature rating performance out of any EN rated sleeping bag, pair it with a mattress with at least R-value 5.