A cosy night’s sleep under the stars is wonderful – but in the harsh and variable Australian climate, ‘cosy’ can be hard to achieve without the right sleeping bag. Sleeping bags can be an expensive purchase, but if treated well can last and perform well for many years. Ensuring you purchase the right sleeping bag for all your outdoor activities is important. This blog will discuss how to choose between down and synthetics, the features to look for in a sleeping bag, and how to treat your new bag to ensure sufficient warmth for years to come.
In general, there are two types of sleeping bag fill available on the market: down and synthetic. Each type has advantages and disadvantages, and it is important to weigh up these factors before making your choice.
Ready to shop? See our pick of the best sleeping bags for 2026 here — including top picks for hiking, camping, kids, couples, and cold weather.
Down-Filled Sleeping Bags
Down is the breast feathers of birds, and the traditional filling for sleeping bags. Most quality down is from ducks and geese, collected from their nests after it falls off the bird. Or, in some cases, it’s 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 in use, measured in cubic inches per ounce. Generally, a low end down sleeping bag or quilt will be approximately 400, while the top of the range can reach as high as 950. The higher the number the more the downs ability to ‘fluff up’. To paint it in simple terms, if a container requires 10 grams of 600 loft down to fill it up, it may only need 5 grams of 950 lift down to fill the same space.
Advantages of down for sleeping bags
The main advantages of down are 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. 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 for sleeping bags
The overwhelming disadvantage of down is its performance when wet. A soggy down bag will only retain about 10% of its warmth, and takes a lot of drying. More modern down is treated to resist moisture, but this is more to manage small amounts of moisture i.e. condensation.
Down is also 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, they are definitely a worthwhile investment.
Synthetic-Filled Sleeping Bags
Synthetic sleeping bags are a more modern alternative to down, and always improving. 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. As the quality of the synthetic fill is improving all the time, synthetic sleeping bags are becoming both 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.
Advantages of Synthetic Sleeping Bags
The main advantages of synthetic bags are both 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 quicker. That said, always endeavour to keep your sleeping bag dry.
Synthetic bags are considerably cheaper than down bags too, at most levels of performance. They’re a good starting point if you don’t want to make a large long-term investment.
Disadvantages of Synthetic Sleeping Bags
Unfortunately, synthetic bags don’t last as long as down bags, they lose warmth as the synthetic breaks down, but given their lower price you still get your dollars worth of use out of them, you just ned up replacing it sooner, especially if used regularly.
Synthetic bags are also heavier and bulkier than down bags for their equivalent temperature ratings, especially for extreme conditions. They’re generally best for car camping or local holidays, where weight and bulk are of minimal concern, and where low cost is important.
Synthetic-filled bags are great for kids who either grow out of bags quickly or need something for school camps – but generally not as good as down bags for hiking, unless you expect to get very wet!
Which Sleeping Bag Shell Fabrics Are Best
Match your sleeping bag to your activity, shell fabrics consist of everything from heavy duty canvas to ultralight polyester.
- A wet or torn sleeping bag performs badly, consider the durability of the shell and match it with your activity. Ultralight bags are made with weight as the fore-feature and may not be as suitable for rougher 4WD adventures as a cotton canvas shell.
- You don’t need waterproof breathable membranes or fabrics waterproof unless you expect to sleep in a river (it happens, believe me). Sleeping bags are full of stitching and are not waterproof by design anyway. That said, some water resistance will go a long way towards improving the performance of the bag especially in the foot area where it can touch the end of the tent.
- Most fabrics used in sleeping bags are very light and 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 the quality, the better the warmth per weight in both synthetic and down filling. Generally, go as high as you can afford – but ensure you know what you are looking at. Some of the numbers quoted can be deceiving.
Sleeping Bag Design Considerations
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 prevent sweltering on a warm night, while zipping it up will keep you warmer when it’s cold.
- A hood will keep your head warm and improve heat retention, and mummy contoured or tapered designs can help prevent the heat escaping from around your body.
- Some bags have zips across the feet, to allow for versatility. Others have this as a sealed section, often on alpine style bags to make it more efficient.
- Make sure to choose the design that suits your requirements best, crawl in the bag and ensure you have the shoulder and hip space you need to be comfortable. Tapered lightweight bags will generally be closer fitting around your body, square shaped bags for camping offer much more wiggle room.
By considering these points, your sleeping bag will keep you warm and give you a good night’s sleep, year after year.
Caring for Your Sleeping Bag
Sleeping bags are generally a simple piece of gear, however they 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.
Keep it Dry!
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 in your pack, or just out in the open. If you can find a waterproof sack, this can help to keep the sleeping bag dry – if not, I highly recommend keeping your sleeping bag inside a dry sack if you are expecting any rain.
Use a Liner Wherever Possible
Using a liner or wearing clothes in a sleeping bag will avoid the need to wash the bag. Using a liner can also add warmth; a simple cotton or a silk liner can add a few degrees to most sleeping bags, while some technical liners can add up to (an albeit ambitious) 15 degrees.
Washing your Sleeping Bag
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, its recommended to follow the washing instructions on the bag, as they can vary – however, don’t use bleaches. Never iron or dry-clean the bag either, and always allow plenty of time to dry.
Down bags should really be hand-washed to prevent damage, you will probably need to use a bath. Fill it with warm water and add down wash. Submerge the bag, jostle it around, and squeeze it to move the soap through. Leave to soak for 30-40 minutes, then move it around in the water again to further move the soap through.
Let the water out of the bath and, without lifting out of the bath, squeeze the water from 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 out any excess soap. You will likely need to repeat this step several times to ensure you’ve ridded the bag of all soap.
Once rinsed, squeeze the bag out into the bath and allow to dry. This may take several days, however it is vital that the bag is totally dry before used or stored.
If you do need to wash your down bag, check out our full guide here >>
Wrap Up
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 major purchase, however they are vital for a good night’s sleep. Choosing between down and synthetic bags can be difficult if you are on a budget – so just make sure you look into where and how you intend to use it. As mentioned, they can often be worth a large initial investment for both long-term performance and the joy of a good night’s sleep!
Now you know what to look for, see our top sleeping bag picks for 2026 — or browse the full sleeping bag range at Snowys.
Hi my name is Simon. I’ve been travelling with my family and friends through the great outdoors for many, many years. I’ve hiked in all sorts of terrain from the alpine fjords of Norway, through the storms of South West Tasmania, to the arid, unforgiving landscapes of the Northern Flinders, as well as just day walks around the Adelaide hills whenever I have the chance. I’ve been a part of the Scouts for the best part of 10 years, and have led camps and hikes through all corners of the country. I’m also involved in rogaining, rock climbing, caving, geocaching, sailing and kayaking. When I’m not outside climbing mountains and looking for views, I’m a student, studying Aerospace Engineering and Physics.
Informative read! Thanks for the useful info. Great share!