Sleeping bag science

Your sleeping bag and whatever it rests on are your best camping friends after your tent.

It is a real delight to snuggle down in your sleeping bag for the night. And, it is even better to wake and settle back for a lie in when cocooned in your warm shell against the early morning cold. 

While you can check out mats here let’s take some time to consider the sleeping bag. These come in single or double options and all comprise a shell fabric that should be easy to clean and nice to touch; an internal fabric that should provide next-to-skin comfort that keeps you free from heat sapping and clammy moisture; and insulation that sits between the two. A zip allows easy access and the chance to regulate heat. Zips sometimes allow single sleeping bags to be attached together to make a double or can be undone completely to create a duvet.


Fillings and construction
Insulation works by trapping a layer of warm still air between you and the cold outdoors. Down is generally considered to be the ultimate fill as it provides superb insulation while being very light. It compresses to a small size for convenient storage and transportation, and, when released, it quickly springs open (or lofts) to trap a vast amount of air. Sleeping bags using this fill are designed to ensure down efficiently lofts. Unfortunately, down is very expensive and clumps together when damp to lose its loft and insulation.

A synthetic fill is the most cost-effective and user-friendly option. It is easy to maintain and works even when damp, although it is heavier and bulkier than down when packed away. Sheets of the insulation are sewn between the inner and outer fabrics. The thread will compress the synthetic fill and cause cold spots. While this doesn’t matter in a sleeping bag designed for high summer use, it can be a problem in colder weather. An off-set second layer is placed over the first to ensure a uniform depth of fill to get around this in sleeping bags designed for camping late season or in colder conditions. Some sleeping bags also have a second loose outer layer to cover the thread.

Sleeping bags come in various insulation thicknesses that allow you to tailor warmth to meet needs. To help you choose, we categorise our sleeping bags in two ways.

Temperature ratings
All our sleeping bags are independently tested to European standards to find their temperature rating. This uses a computer-controlled thermal measurement mannequin that mimics a sleeping human to objectively determine and compare the sleeping bag’s insulation values and temperature limits. The resulting Tcomfort, Tlimit, and Textreme figures are useful when comparing sleeping bags across brands. 

We also supply a season rating to help you quickly assess a sleeping bag. If we rate a sleeping bag 1 season, we consider it for use in summer months only; 2 seasons for use from late spring through to early autumn; 3 seasons for use from spring right through autumn; 4 seasons for use throughout all seasons but more suited to colder conditions.


The shape of the bag is also important to sleep comfort. Rectangular bags (envelope) give extra wiggle room and mummy sleeping bags fit closer round the legs to keep you warmer by reducing the air that requires heating. Mummy bags also have a smaller pack size. Hybrid profiles have been designed to enhance characteristics, like space to move during the night. Shorter sleeping bags offer warmer options for small people and children. 


Sleeping bags can include features that are helpful at night. Some, like zip baffles, hoods and draw cords, enhance insulation to improve performance so demand consideration – especially in areas like kids sleeping bags that should have drawcords replaced by elastic for safety. Other features are not so important but useful. These include pockets to keep small items close to hand – perfect for tissues and small torch. 


While down sleeping bags require special care, synthetic versions are far easier to look after. You can start straight away by sponging off any spills or dirt as soon as they occur. The use of a sleeping bag liner not only adds a little extra warmth on colder nights but can be used as a cover on its own when temperatures rise. And they simply pop into the washing machine when dirty…

A dirty sleeping bag is a tad harder to clean. Few domestic washing machines can handle a sleeping bag given the bulk and weight, and you might have to resort in a trip to the launderette or get it dry cleaned. If you choose the latter method make sure the sleeping bag is well aired before use as the fumes can prove deadly. 

Many campers soak the sleeping bag in the bath, agitating the water and gently treading in a proprietary sleeping bag cleaner to remove dirt – a great way to also wash your feet! Rinse the sleeping bag in plenty of clean water before hanging out to dry thoroughly. 

Try to store your sleeping bag by hanging it up where it can be aired to prevent any musty smell. If necessary, store loose in a mesh bag. When in transit always stuff it into the supplied carrybag (stuff sack) as this preserves the insulation.

You’ll be pleased to hear that Easy Camp offers a choice of easy-to-maintain single and double sleeping bags in different thicknesses and designs to suit needs. Check out the range here


Easy Camp sleeping bags

See our range of sleeping bags and get inspired for you next purchase


Easy Camp sleeping bags

See our range of sleeping bags and get inspired for you next purchase