Choosing The Right Sleeping Bag: 20 Or 30 Degrees?

When choosing a sleeping bag, the key factor is its temperature rating. The decision between a 20-degree or 30-degree bag depends on various factors, such as the environment, your body type, and your hiking and sleeping style. While a 30-degree bag may be suitable for milder climates, a 20-degree bag is more versatile and suitable for colder temperatures. Additionally, factors like the bag's shape, insulation type, and extra features, such as draft collars, hoods, and draft tubes, can also influence your decision. It's important to consider your personal preferences and the specific conditions in which you'll be using the sleeping bag to make an informed choice.

Sleeping bag temperature ratings are estimates

Sleeping bag ratings are a complicated topic, and it can be tricky to know whether to opt for a 20 or 30-degree bag. Sleeping bag temperature ratings are estimates, not exact measurements. While lab testing is standardised, it can't account for individual differences. For example, a person's body type, clothing, gear, and sleeping style can all impact how warm they feel in a sleeping bag.

The EN (European Norm) standard was originally adopted by the sleeping bag industry to provide consistent temperature ratings across brands. This standard involves placing a test dummy, dressed in base layers, inside a sleeping bag on a sleeping pad. The bag is then placed in a cold chamber, and measurements are taken via temperature sensors on the dummy as the temperature drops. This test produces a rating range for each sleeping bag, with two specific temperature ratings: the comfort rating and the lower limit rating. The comfort rating indicates the temperature at which a cold sleeper might feel comfortable, while the lower limit rating is the temperature at which a warm sleeper might still be comfortable.

Today, the ISO (International Standards Organization) oversees bag testing, using the ISO 23537 standard, which is similar to the EN test. The ISO test uses a heavily instrumented electronic mannequin, dressed in long underwear, to measure the amount of electrical energy needed to maintain its temperature as the air temperature cools. This test also provides three temperature thresholds: comfort, limit, and extreme ratings. The comfort rating is based on the temperature at which the "average female" can sleep comfortably, while the limit rating is based on the temperature at which the "average man" can maintain thermal equilibrium without shivering or risking hypothermia.

It's important to note that not all sleeping bags have an ISO or EN rating. These standards don't apply to bags designed for extreme cold, children's bags, or bags intended for mild conditions or casual use. In these cases, the temperature rating is likely the brand's estimate, not an ISO or EN-tested rating. Therefore, it's essential to use these specs as rough guidelines rather than exact comparisons between brands.

When choosing between a 20 or 30-degree bag, consider the coldest conditions you anticipate and select a bag that will keep you warm at or below that temperature. Additionally, think about your sleeping style and whether you tend to get cold at night. If you're planning to hike in the Cascades during the summer, a 30-degree bag might suffice, while a 20-degree bag could be necessary for the Rockies. If you're a cold sleeper, you may need to bring extra insulation or opt for a warmer bag.

In summary, sleeping bag temperature ratings are estimates based on standardised lab tests. Individual factors, such as body type and clothing, can impact the actual comfort level of a sleeping bag. When choosing between a 20 or 30-degree bag, consider the anticipated temperatures, your sleeping style, and the specific features of the bag to make an informed decision.

Lab testing simulates how a sleeping bag is used

When choosing a sleeping bag, the key factor is its temperature rating. Sleeping bag temperature ratings are a complicated subject, and it is important to understand how these ratings are determined through lab testing, as well as the limitations of this process.

In the past, brands tested sleeping bags in their own labs using different methods, making it difficult to compare products from different companies. To address this issue, the sleeping bag industry adopted standardised testing methods, originally under the EN (European Norm) standard, and now overseen by the ISO (International Standards Organization). Most brands now send their sleeping bags to independent labs for testing, which assign temperature ratings.

When deciding between a 20-degree or 30-degree sleeping bag, consider the temperature range you anticipate encountering during your outdoor adventures. A 20-degree bag is commonly used and provides more flexibility, especially if you tend to get cold at night. It is also a good choice if you are not prepared for the extra fuss of bringing additional clothing or insulation for layering. A 30-degree bag may be suitable for warmer summer temperatures, but you may need to bring extra clothing or a puffy jacket to stay warm in colder conditions.

Additionally, consider your personal preferences and sleeping style. If you tend to sleep warm, a 30-degree bag with layering options may be sufficient. However, if you are a cold sleeper or prefer more room, a 20-degree bag with a larger girth could be a better choice. Ultimately, the decision between a 20-degree or 30-degree sleeping bag depends on your specific needs and the expected temperature range of your outdoor activities.

The ISO (International Standards Organization) oversees bag testing

The temperature rating is a key factor when choosing a sleeping bag. The ISO (International Standards Organization) oversees bag testing, which is done in a laboratory. The ISO 23537 standard, commonly known as the EN rating, provides a consistent, though imperfect, way to measure and report temperature ratings. The ISO 23537-1:2016 standard specifies the requirements, test methods, and provisions for labelling adult-sized sleeping bags for sports and leisure use. It does not apply to bags for children or babies, military use, or extreme climate zone expeditions.

The ISO test method involves placing a sleeping bag and a test dummy dressed in base layers on a sleeping pad in a climate-controlled room. This protocol ensures consistency across bag tests, but it cannot account for all variables, such as differences in clothing, gear, body types, weather conditions, and individual metabolism. Therefore, the temperature rating on a sleeping bag is an estimate rather than a guarantee of comfort.

The ISO replaced the European Norm (EN) standard, which was previously used by the sleeping bag industry. The EN standard was the first widely adopted international standard for measuring sleeping bag temperature ratings. Despite the change, many backpackers and retailers still refer to the EN rating when discussing sleeping bags. The ISO testing method is very similar to the EN test, allowing consumers to compare old EN-rated bags with newer ISO-rated bags.

When choosing between a 20-degree or 30-degree sleeping bag, consider the coldest conditions you anticipate encountering. If you expect temperatures below 20 degrees, a 20-degree bag will provide more warmth. However, if you prefer to pack light and are willing to rely on additional clothing or a puffy jacket, a 30-degree bag may be sufficient. Additionally, if you tend to sleep warm, a 30-degree bag might offer more comfort without causing overheating.

It is worth noting that temperature ratings on sleeping bags are often rounded to the nearest 0 or 5. For example, a bag named "Snugglebuggle 15" might have an actual ISO lower-limit rating of 18 degrees Fahrenheit. Therefore, it is important to treat the temperature ratings as estimates and be prepared to adjust with extra layers or a liner if needed.

Sleeping bag temperature ratings are a complicated subject

Secondly, the numbers on bag names don't always match exact temperature ratings. Brands often round up or down to the nearest 0 or 5 for simplicity, so a bag named "15" might have a lower limit rating of 18 degrees Fahrenheit. Additionally, not all sleeping bags have ISO (International Standards Organization) or EN (European Norm) ratings. These standards don't apply to bags designed for extreme cold, children's bags, or those intended for mild conditions or casual use. In such cases, the temperature rating is the brand's estimate, not a standardized rating.

Thirdly, the rating you choose depends on various factors, including your sleeping style (warm or cold sleeper), hiking style, and the anticipated coldest conditions. If you tend to feel cold, especially in your legs or feet, you may need a warmer bag or additional insulation. For three-season camping in the mountains of the Western US, most people recommend a synthetic sleeping bag rated at 20 degrees Fahrenheit or less. However, if you prefer lightweight gear, a goose down bag rated to 20 degrees or less is a better option.

Lastly, it's worth noting that temperature ratings are just estimates, and other factors can affect the warmth of your sleeping bag. For example, the more you stuff and unstuff your bag, the less insulating ability it has. Additionally, synthetic bags are generally recommended for summer camping as they dry faster and retain insulation when wet, while goose down bags provide the most warmth for their weight but require careful handling to keep them dry. Understanding these complexities will help you make a more informed decision when choosing between a 20-degree or 30-degree sleeping bag.

A 20-degree bag may be too warm in summer

When choosing a sleeping bag, the key factor is its temperature rating. However, it's important to remember that temperature ratings are estimates, and the comfort level you experience in your sleeping bag may differ from its tested temperature rating. Lab testing can't account for variables such as differences in people's body types, clothing, gear, and sleeping styles.

Additionally, your choice between a 20-degree and 30-degree bag depends on your personal preferences and sleeping habits. If you're a warm sleeper or tend to sleep warm, a 30-degree bag will provide more comfort during the summer months. On the other hand, if you're a cold sleeper or tend to feel chilly at night, a 20-degree bag might be necessary, even in summer.

It's worth noting that you can adjust the warmth of a sleeping bag by using supplemental clothing or a liner. If you opt for a 30-degree bag and find it too cold on chilly summer nights, you can add a puffy jacket or extra layers to increase warmth. Similarly, if you choose a 20-degree bag and find it too warm, you can unzip it or stick a leg out, as some bags have full zips that make it easier to regulate temperature.

In summary, when deciding between a 20-degree and 30-degree sleeping bag, consider the expected temperatures during your camping trips, your personal sleeping habits, and your preference for sleeping with extra clothing or layers. Remember that a 20-degree bag may be too warm in summer, especially in hotter regions or if you're a warm sleeper, but you can always adjust the temperature by unzipping the bag or adding extra layers as needed.

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