How to Choose the Perfect Sleeping Bag


A cosy night’s sleep under the stars is wonderful, but in the harsh and variable Australian climate, cosy can be hard to come by without the right sleeping bag. Sleeping bags can be an expensive purchase, however, if they are treated well they can last, and perform well for many years.

Making sure you get the right sleeping bag for all your outdoor activities is very important. This post will discuss how you choose between down and synthetics, what to look for in a sleeping bag and how to treat your new sleeping bag to ensure it keeps you warm for many years to come.

In general, there are two types of sleeping bag fill available on the market, the traditional down, and the more modern synthetics. Each type has advantages and disadvantages, and it is important to weigh up these factors before making your choice.

Down Filled Sleeping Bags

Down is the traditional filling for sleeping bags and  is the breast feathers of birds. Most quality down is from ducks and geese and is collected from their nests after it falls off the bird, or in some cases is a by-product of the food processing industry.

The quality of down is measured by fill power. This is basically a measure of how much the down will “fluff up” when it is in use, measured in cubic inches per ounce.

Generally, a low end down sleeping bag or quilt will be approximately 400, and the top of the range can get as high as 900.The more a bag “fluffs up” the better the insulating properties, and hence less weight of filling is required, to keep you just as warm

Sleeping Bag Down

There are many advantages and disadvantages of down sleeping bags, so let’s take a look at them.

Advantages of down

  • The main advantage of down is the warmth per weight and longevity.
  • Generally, down bags can be half the weight of a comparatively warm
    synthetic bag, and compress much further. This means less weight on your back if you are hiking, and less to cart around camp from the car. They also have a longer lifespan.
  • A down bag will keep filling and stay warm for years even with regular use, whereas a synthetic bag will eventually lose its warmth.
  • Some sources suggest a down bag will last two to three times as long as an equivalent synthetic bag.

Disadvantages of down

  • The overwhelming disadvantage of down is its performance when it gets wet.
  • A soggy down bag will only retain about 10% of its warmth and takes a lot of drying.
  • Down is generally more expensive as an initial purchase, however, the long-life of a down bag means it will generally be cheaper in the long term.
  • Down bags are a long-term purchase that may be unwarranted for some applications such as school camps, or if they are only being used occasionally for local summer holidays. However, if you expect to use them regularly over a long period of time, a down sleeping bag is a definitely worthwhile investment.

Sleeping Bag Down Fill Power

Synthetic Filled Sleeping Bags

Synthetic sleeping bags are a more modern alternative to down and are being improved all the time. The fill is a polyester microfibre that can be compressed, then”fluffs up” to provide insulation when released.

Generally the greater the mass of synthetic measured in grams per square metre (gsm), the warmer it will be. However, it will be heavier as well. The quality of the synthetic fill is improving all the time, so synthetic sleeping bags are getting lighter and warmer.

Synthetic fillers vary widely, with most manufacturers having their own specific type of fill. This means there is no standard for the quality of the filler. However, these manufacturers make their name on quality, so if the filling is poor, the company is probably on the way out.

There are many advantages and disadvantages to synthetic sleeping bags which we’ll examine below.

Advantages of synthetic

  • The main advantages of synthetic bags are their performance when wet, and the initial cost.
  • Synthetic bags will retain about 50% of their dry performance when wet, which is far better than down bags.
  • Synthetic bags also dry out quickly compared to down bags.
  • Despite this, always endeavour to keep your sleeping bag dry.
  • Synthetic bags are considerably cheaper that down bags at most levels of performance.

Disadvantages of synthetic

  • Unfortunately, synthetic bags don’t last as long as down bags and may lose a lot of their warmth inside five years, if they are used regularly.
  • Synthetic bags are also heavier and bulkier than down bags, especially for extreme conditions.
  • Synthetic bags are generally best for car camping, or local holidays, and where weight and bulk are of minimal concern, and low cost is important.
  • They can also be great for kids who either grow out of bags quickly or need something for school camps.
  • Synthetic bags are generally not as good as down bags for hiking unless you expect to get very wet.
  • Synthetic sleeping bags are a good starting point if you don’t want to make a large long term investment.

What to look for in a sleeping bag

When buying a sleeping bag, there are several things to look for including the quality of fabric, quality of filling, carry sack, and design.

  • A wet or torn sleeping bag performs badly, so it is a good idea to look for fabrics that are waterproof or at least water-resistant.
  • You don’t necessarily need to go looking for waterproof breathable membranes, or fabrics waterproof to 10000mm unless you expect to sleep in a river (it happens, believe me), but a bit of water resistance will go a long way towards improving the performance of the bag.
  • Most fabrics used in sleeping bags are very light, and very strong, but look for any obvious signs of wear and tear each time you use the bag, and fix them as soon as you can.
  • The quality of filling is a big factor, the higher quality, the better warmth per weight in both synthetic and down filling.
  • Generally go as high as you can afford, but make sure you know what you are looking at, as some of the numbers quoted can be deceiving.


Finally, the design is an important feature. Unless you are going for weight savings over comfort a full length zipped bag is a good idea.

  • A zip can make a sleeping bag much more versatile. Unzipping the bag will stop you from sweltering when it is a warm night. While zipping it up will keep you warmer when it is cold.
  • A hood will keep your head warm and so improve heat retention, and “mummy” contoured or tapered designs can help to stop the heat escaping from around your body.
  • Some bags have zips across the feet, to allow for versatility. Others have this as a solid section which is warmer.
  • Make sure you choose the design that suits your requirements best.

By considering these points, your sleeping bag will keep you warm, and give you a good night’s sleep for years to come.

Couple laughing snugged up in Sea to Summit Sleeping Bags

Sleeping bag maintenance

Sleeping bags are generally a simple piece of gear, however, they do require some basic care to keep them in top shape.

When you don’t need your bag compressed, leave it loose. Most bags come with a large bag for storage and a small bag for compression. If you don’t have one of these larger bags, hang your sleeping bag in a closet, store it in a pillow case, or at least leave the compression straps as loose as you can.

Dry it!

Down loses 90% of its warmth when wet, and synthetics lose 50%. So make sure you leave your bag out to dry before storing it. As well as degrading the performance, a wet sleeping bag is a warm, moist environment perfect for bacteria.

The place a sleeping bag is most likely to get wet when not in use is sitting in your pack, or just out in the open.

If you can get a waterproof sack it can help to keep the sleeping bag dry, and if not, I highly recommend keeping your sleeping bag inside a dry sack if you are expecting any rain.

Keep it clean where ever possible

Using a liner or wearing clothes in a sleeping bag will help to avoid needing to wash the bag. Using a liner can also add warmth to the sleeping bag. A simple cotton or a silk liner can add a few degrees of warmth to most sleeping bags, and some technical liners can add up to 15 degrees (although this rating is a bit ambitious).

Cleaning a sleeping bag can be a daunting task, especially for down bags and should be avoided where possible. It is possible to have down sleeping bags professionally washed. Contact either a local manufacturer or an outdoor store for advice on who to contact in your area.

Synthetic sleeping bags can be machine washed at low temperatures, on a delicate setting using a mild soap and a lot of rinsing. Generally follow the washing instructions on the bag, as they can vary, however, don’t use bleaches. Never iron or dry clean the bag and always give it lots of time to dry.

Washing a down bag

They must be hand washed, so you will probably need to use a bath to fit it in. Fill the bath with warm water and add a mild soap. Submerge the bag, move it around and squeeze it to get the soap through. Leave it to soak for 30-40 minutes then move it around again to get the soap further through.

Let the water out of the bath, then without lifting the bag out of the bath, squeeze the water out of the bag. If you lift the bag, the weight of the soaked down can cause the internal baffles to tear. Refill the bath with warm water and move the bag about to rinse the soap out.

You will probably have to rinse it several times to make sure all the soap is out. Once it is rinsed, squeeze the bag out in the bath, and let it dry. It may take several days to dry properly, however it is vital that the bag is totally dry before it is used or stored.

Caring for your bag

Caring for a sleeping bag is a simple and quick process. With correct care, your sleeping bag will keep you warm for a long time.

Sleeping bags can be a large purchase, however, they are vital for getting a good night’s sleep. Choosing between down and synthetic bags can be difficult if you are on a budget. However, make sure you look into where and how you intend to use it.

Sleeping bags can perform well for a long time if cared for correctly. They can often be worth a large initial investment for long-term performance, and the joy of a good night’s sleep.

Check out the range of sleeping bags at Snowys to get some more ideas, and let us know if you have any extra thoughts on what makes a great sleeping bag!

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Joined back in July, 2012

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