When folks complain to me that their sleeping bag isn’t heat sufficient, the very first thing I ask them is to inform me the R-value of their sleeping pad. As a result of, if it’s underneath R=5.38 and your sleeping bag has an EN/ISO-certified temperature ranking, you’re unlikely to understand the bag’s full insulation potential. For those who’re utilizing a sleeping pad with a decrease R-value to avoid wasting gear weight, as an illustration, upgrading to a pad with a considerably larger R-value ought to enhance your consolation degree.
The Backside Line. Your sleeping bag’s temperature ranking assumes that you just’re utilizing a sleeping pad with an R-value of 5.38 or extra. If the pad’s R-value is decrease, you’ll sleep colder and your sleeping bag received’t really feel as heat when temperatures drop.
Sleeping Pad R-Values: 101
An R-Worth measures the insulation degree of a sleeping pad, or how a lot it protects you from warmth loss as temperatures get colder. Pads with larger R-Values will maintain you hotter in colder climate than these with decrease R-values.
Many sleeping pad producers ship their merchandise to impartial testing labs to have their R-values examined, utilizing an industry-standard referred to as ASTM F3340-18 that was rolled out in 2020. The testing equipment and methodology is standardized so shoppers can evaluate the R-values of various sleeping pads or manufacturers to at least one one other. In different phrases, so everyone seems to be singing from the identical sheet of music. Earlier than the usual, there was no good technique to evaluate sleeping pads as a result of everybody used a special approach of ranking them in the event that they have been measured in any respect.
Sleeping Bag Temperature Rankings: 101
Many sleeping bag producers (and some quilt makers) additionally ship their merchandise to check labs, so shoppers can evaluate the temperature scores of baggage from completely different producers. As an example, in case your sleeping bag has a Consolation or Decrease Restrict temperature ranking, it’s in all probability been examined utilizing the European Norm 13537 commonplace or the ISO 23537 sleeping bag ranking commonplace which subsumed it. These are sometimes abbreviated as EN/ISO on labels and so they’re basically equal.
The testing equipment used to generate these scores requires a sleeping pad with an R-value of 5.38 and assumes you’re additionally sporting lengthy underwear (high and backside) and a heat hat.
What do these Sleeping Bag Temperature Rankings Imply?
There are three completely different temperatures measured by the EN/ISO checks: consolation, transition, and danger.
- The consolation ranking measures the bottom temperature the place the “common” lady shall be comfy, relaxed, and never feeling chilly.
- The transition ranking measures the bottom temperature the place the “common” man will sleep comfortably, with out shivering. Males have extra physique mass than ladies and generate extra physique warmth, to allow them to tolerate decrease temperatures.
- The intense ranking measures the bottom temperature a girl can survive utilizing the sleeping bag. Any decrease and so they’re at a excessive danger of hypothermia and demise.
On this instance of the Massive Agnes Torchlight 30 (males’s/unisex) sleeping bag, the bag temperature ranking for a girl utilizing the unisex Torchlight 30 can be 35 (F)/ 2 (C), and the boys’s ranking can be 25 (F)/-4 (C). Most individuals don’t take note of the acute ranking a lot as a result of it not going to be comfy.
Notice that the bag is labeled a “Torchlight 30” and never a “Torchlight 25”, which is the boys’s ranking. Many sleeping bag producers are usually not clear in how they label their luggage, typically “rounding” up or down numbers to suit some buyer profile. It’s advertising. Learn the labels.
Who will get their sleeping pads and luggage rated by these requirements?
For those who store at REI, they and NEMO, Therm-a-Relaxation, Massive Agnes, Exped, Klymit, Sea-to-Summit, Rab, The North Face, Sierra Designs, Mountain Hardwear, Marmot, Kelty, Coleman, and Mountain Tools, all ship their merchandise to check labs to be rated utilizing these requirements so clients can evaluate them and decide those that match their wants.
However, many firms nonetheless don’t abide by these requirements, together with many smaller producers and off-shore manufacturers that resell low-cost sleeping luggage and pads on Amazon, eBay, or AliExpress. They depend on repute or buyer critiques as an alternative of sending their merchandise out to be examined.
What about backpacking quilts?
Some testing labs have tailored the EN/ISO commonplace to check backpacking quilts and I’ve heard of some firms that ship their quilts out to be rated. Nevertheless it’s fairly uncommon. You have to depend on vendor repute and buyer critiques as an alternative.
So What’s the Impact of R-Worth on Temperature Rankings?
Since EN/ISO sleeping bag temperature scores are based mostly on using a sleeping pad with an ASTM R-value of 5.38, lengthy underwear, and a hat, it will stand to motive that your sleeping bag is not going to maintain you as heat for those who use a pad with a decrease R-value or don’t put on sleeping garments.
How a lot colder, is actually going to rely upon the design of the sleeping bag and the exterior temperature when it’s used. Until each permutation is examined, there’s no formulation or graph that can inform the minimal consolation or decrease restrict temperature of your sleeping bag on high of a given pad at completely different air temperature. It would additionally differ for each sleeping bag as a result of they’re all designed in a different way with completely different “components.” There are additionally particular person variations than can have an effect on your heat degree, whether or not you’re a heat sleeper or a chilly sleeper.
However understanding in regards to the interdependency between sleeping pad R-values and sleeping bag temperature scores calls into doubt using low-weight sleeping pads with low R-values when the exterior temperature is near the Consolation or Decrease Restrict of your sleeping bag.
You would possibly even ask:
- Why anybody would hassle to get a sleeping pad with an R-value under 5.38, to start with, when it’s a straightforward approach to make sure that you’re getting the very best insulation worth out of your sleeping bag?
- Why do sleeping pad producers make pads which have a decrease R-value than 5.38 when sleeping bag temperature scores rely upon that minimal?
- Why is that this so sophisticated to determine?
- Why don’t firms promote built-in sleep techniques that embrace a sleeping bag and a sleeping pad collectively to take the guesswork out of all this?
For those who’re desirous about upgrading your present sleeping pad to at least one with the next R-value, listed below are those presently obtainable with ASTM F3340-18 R-values between 4 and eight. I’ve included that vary to provide you a way of the burden and heat tradeoffs obtainable.
For a whole record of all of the pads with ASTM F3340-18 R-values, see our article Sleeping Pads R-Values of 2022. Since R-values are additive, you could need to carry two pads on journeys while you anticipate the necessity for further heat, as an alternative of 1 pad.
See Additionally
SectionHiker is reader-supported. We independently analysis, check, and fee the very best merchandise. We solely earn cash if you are going to buy a product by our affiliate hyperlinks. Assist us proceed to check and write unsponsored and impartial gear critiques, newbie FAQs, and free climbing guides.
