Sleeping Bags

A sleeping bag is something that most people have used or owned in their lifetime, whether it was used for a school camp or if you and your family are long time, seasoned campers. But not all sleeping bags are created equal and not all sleeping bags can be used year round or are suitable for every single trip you undertake.

What is the purpose of a sleeping bag?

The purpose of a sleeping bag is to keep the user warm by trapping body heat. The comfort ratings developed for sleeping bags are developed for the average person.

The purpose of a sleeping bag is to keep the user warm by trapping body heat. The comfort ratings developed for sleeping bags which are used by most manufacturers are developed for the average person using EN/ISO (EN 13537) standards developed in 2002 and is still the only international rating system set by a standardised laboratory test.

Is there a sleeping bag that can be used for everything?

Season, weather, and location all play a vital role in the quality of your sleep as does your personal sleeping habits and whether you are a "cold sleeper" or a "hot sleeper". So, it is possible to use the same sleeping bag over and over if you are only participating in activities in one type of climate in one type of season, however, if you are tripping around, a sleeping bag used for summer conditions will not keep you warm enough in the winter time. But the general rule of thumb is to purchase a sleeping bag that will best suit you for 80% of it's usage then value add or take away depending on your needs or climate. Or if you you have plenty of space and cash you can always purchase multiple sleeping bags.

Understanding Sleeping Bags

The entire sleeping setup can be the difference between an undisturbed and a disgruntled night’s sleep. Sleeping in a smaller, enclosed space such as a Swag will allow body heat to fill up the space at a faster rate and keep it balanced throughout the night. Sleeping in a larger space such as a tent will mean cold air will linger throughout the night.

People respond differently to various conditions. A smaller sized person may be a colder sleeper as there is more free space within the sleeping bag. A larger sized person will rapidly trap body heat within the sleeping bag.

A restful sleep can be determined by the current physical state of the user. Someone who is hungry will be colder through the night as the body consumes more energy to stay warm. Likewise the materials used in the construction of a sleeping bag, play a major role in how the user will sleep. A down sleeping bag may provide more warmth than a synthetic sleeping bag and likewise a cotton canvas sleeping bag with a flannel linking may be more comfortable against the skin and retain more body heat than a synthetic lining.

How are sleeping bag's temperature ratings set?

EN/ISO Sleeping Bag Temperature Ratings (EN 13537)

You will soon work out that not all sleeping bag manufacturers have the huge range of sleeping bags at various temperature ratings, however most manufacturers' sleeping bags are all tested using the same protocols, if they are not tested using the same EN/ISO ratings, most manufacturers will provide a Comfort Rating and and Extreme Rating for a buyers reference. For the most part, manufactures will provide a tiered system temperature ratings for the sleeping bag and often it's the "extreme" limit of the sleeping bag that is advertised in the name. Some manufacturers may only provide the Comfort and Extreme ratings.

Be sure to check all of the details of the sleeping bag to make sure you get the right one for the right occasion.

The EN/ISO EN 13537 testing protocols were developed in Europe in 2002 and are the standard for sleeping bag ratings. The ratings from these protocols allow users to compare bags that test to this standard and safely choose a sleeping bag that suits their needs/requirements.

Comfort Range: The comfort limit, is based on the 'average' women (yes a woman) having a comfortable sleep. Usually taking into consideration a base layer of some description (t-shirt and shorts/pants) and the person being relaxed and comfortable and not feeling the cold.

Transition Range: This is usually the 'lower limit' of the transition range which is the lower limit where the average man (yep, man) can still have a nights sleep but is in a situation of fighting against the cold, he may be curled up but in thermal equilibrium and not shivering. That means that somewhere within this range is likely to be the performance limit of the sleeping bag. For example the comfort rating of a sleeping bag may be 0°C and the extreme limit may be -5°C, therefore the Transition Range may be somewhere around -2°C to -3°C.

Extreme Range: As per the EN/ISO standard language, this is the range in which the user will experience a strong sensation of cold, and there is a health risk of hypothermia (in certain conditions). A sleeping bag should only be used in this rage as an 'emergency' or survival situation.

It is important to remember these are just ranges and summer sleeping bags and winter sleeping bags are not created equal with the Extreme Range for a summer sleeping bag being hugely different than that of a winter sleeping bag and similarly the differences will be vast between a winter sleeping bag and a mountaineering sleeping bag as an example.

Each person will have individual results based on their own personal body composition, clothing etc. But nevertheless the standards and ranges, give you a great baseline performance level for a sleeping bag.

​​​​​​​What should you wear inside a sleeping bag?

Appropriate layering of thermal clothing and blankets or sleeping bag liners can allow sleeping bags to become more versatile in various conditions by value adding. The feet and head are control points for body temperature, meaning wearing thermal socks and a beanie can bring your body to a comfortable sleeping temperature in colder conditions. At the end of the day, it is up to the individual user what they choose to wear and when, but clean comfortable clothing is always recommended.

Should or Can you use a blanket or sleeping bag liner?

A sleeping bag liner can be used to provide additional warmth and also helps to keep your sleeping bag cleaner for longer, and long term a sleeping bag liner may help to increase the life of your sleeping bag overall. If you choose to use a blanket, be sure to put the blanket on the inside of the sleeping bag. All sleeping bag’s internal fill are designed to “swell” regardless if you are using a down sleeping bag or a synthetically filled sleeping bag. The fibres swell and trap heat between and around the fibres. If a blanket or something heavy is applied to the outside of the sleeping bag, it prevents the fibres from expanding and trapping heat, meaning the sleeping bag cannot perform as it should, and the user may become uncomfortable especially in cold or extreme climate conditions.

Users who choose to sleep directly outdoors with minimal shelter such as a tarp or awning will experience more discomfort.

With the above indicators, discretion and careful consideration must be used when selecting a suitable sleeping bag, and it may even be a necessity that two sleeping bags are purchased (summer sleeping bag and winter sleeping bag) depending on your requirements or what they are being used for. Additionally sleeping bag liners can be purchased in several varieties, such as fleece, silk, cotton or a combination of silk and cotton which can be easily washed, and swapped out as the seasons change.

At Bundy Outdoors we stock a wide range of sleeping bags that use various materials in their construction for suit any climate. With the above indicators, and the above comfort zone suggestions, discretion and careful consideration must be used when selecting a suitable sleeping bag.