The best sleeping bags for trekking in Nepal

Your sleeping bag is one of the single most important items on a high-altitude Nepal trek. Without a quality winter sleeping bag, you're going to be miserably cold, perhaps even dangerously so!

Whether you're camping or staying in teahouses (guesthouses) on your Nepal trek, you can expect very cold night-time temperatures, as accommodations typically don't heat the bedrooms. Moreover, most teahouse bedrooms have single-pane windows, so it's common to wake up to frozen water bottles in your room.

A typical teahouse bedroom in Nepal

So yes, a quality winter sleeping bag is a total must to keep you warm at night on a Himalayan trek!

We now explain the various things to look for to ensure you choose a great winter sleeping bag.

Let's discuss the main things to look for when choosing a winter sleeping bag, which are:

Winter sleeping bags have either down or synthetic stuffing. Let's look at each in turn ...

Down-filled bags are made using the soft under feathers from ducks or geese. They're the warmest bags and very lightweight, and hence are very popular.

White goose down feathers

That said, while sleeping bags with down fill are for sure incredibly cosy, we encourage you to question how the feathers are sourced if you, like us, wish to ensure they're ethically obtained. To learn more on this important topic, please read the NY Time's What Is Ethical Down?

Here's a summary of the pros and cons of down-filled sleeping bags for cold-weather expeditions ...

Synthetic sleeping bags have fill (filling) made from polyester fibres. They're less expensive than down sleeping bags, and hence popular with those on a budget. They also have the big advantage of retaining most of their heat even if the bag gets damp or wet.

Here is a summary of the pros and cons of winter synthetic sleeping bags ...

The fabrics used to create a sleeping bag's shell and inner lining – the two layers that enclose the bag's fill – are also important considerations.

Sleeping bag manufacturers use a variety of fabrics for the shells and linings, like polyester, nylon, taffeta and polycotton. Polycotton takes a while to dry, so it's not a good option for a wintry expedition like trekking in the Himalayas.

Polyester, nylon, silk and taffeta are breathable and quick-drying, which is what you need for an inner lining because you don't want moisture to stay trapped in the bag. These days most sleeping bag shells and inner linings are made from nylon.

Taffeta is a really great fabric choice for the inner lining, but it's also the most expensive. Silk is wonderfully comfortable, but you have to be very careful to ensure it doesn't tear.

Most sleeping bag shells now come with a durable water repellent (DWR) finish, which helps to keep you dry. It also extends the life of the bag. Nylon linings are very comfortable.

The thinner (and therefore lighter) the fabric of a sleeping bag, the more expensive it is. The specification that indicates this thinness is called the denier (D).

Nylon with a low denier like 10D is very sheer and lightweight. You can usually see through such nylon to the sleeping bag's fill.

A high denier like 40D indicates a relatively thick and heavy fabric. Naturally you want as light a sleeping bag as possible while staying within your budget.

Some sleeping bag manufacturers cut the lining smaller than the shell. That's all that's meant by the term 'differential cut'.

A differential cut in a winter sleeping bag is a good thing because it naturally creates more space between the liner and the shell, which in turn allows the down or synthetic fill to loft (fluff) more easily and thus insulate you better. (We discuss loft in detail in just a moment.)

Baffled by the term baffles?

Baffles are the internal 'walls' in sleeping bags that create compartments which keep sections of fill (usually down) separate from one another. Without baffles, some or all of a bag's fill would migrate to one or a few spots, leaving parts of you less insulated against the cold.

Note that not all sleeping bags use baffles. You get seamless sleeping bags (some prefer to have unrestricted fill), as well as sewn- or stitched-through sleeping bags (these are usually summer sleeping bags).

But baffles and the insulated chambers or channels that they create are very popular among sleeping bag manufacturers, so let's look at the different types out there ...

You get various types of baffle and insulation construction in sleeping bags, including (but not limited to):

Box baffles are inner walls that divvy up the sleeping bag's fill into regularly sized squares, trapezoids or similar. These small insulation chambers are very good at retaining heat. Some sleeping bags even put a second layer of box baffles and insulation chambers – misaligned with those below – for heightened heat retention.

A Western Mountaineering sleeping bag with box baffles

Box baffles produce very insulated sleeping bags, and so are a good option for a sleeping bag that you'll use for trekking in Nepal.

Continuous baffles are horizontal baffles that run all the way around the bag and create long, lateral insulation chambers. Continuous baffles run from the zip all the way round to the draft tube that covers the zip when you do up the bag.

Continuous baffles are often used in season three sleeping bags because in warmer weather you may well want to manoeuvre the fill in such a way that parts of your body are less insulated.

Horizontal baffles are the same as continuous baffles except that there's a side baffle that runs the length of the bag on the opposite side of the bag to the zip and so divides the lateral insulation chambers in two. Thus the lateral insulation chambers created by horizontal baffles are half as long as those of continuous baffles.

A sleeping bag with horizontal baffles

Horizontal baffles are among the best options for winter sleeping bags. For starters, these baffles prevent fill from travelling too far down the bag and so ensure your whole body retains its fair share of insulation.

Secondly, if you're especially feeling the cold on the sky-facing half of your body, you can push around the down fill to bunch on that side for further insulation.

Vertical baffles create very long insulation chambers that are good in winter sleeping bags when used by those who lie on their side. This is because the vertical baffles keep the fill from migrating down on either side of you towards the ground.

Winter sleeping bags sometimes use a mix of baffle styles. For instance, sometimes the foot box in mummy-shaped winter sleeping bags have a vertical baffle just above the feet to create a horizontal insulation chamber over the foot box. This helps to ensure snug feet and so is a good feature.

Your sleeping bag's zip (or zipper) usually runs down the one side of the bag. Some, however, can also go down the front middle, but this isn't common.

Check how far down the zip goes if you want a really easy in and out. We recommend that you opt for a zip that's on the left-hand side if you're right handed, and vice versa. The thinking here is that it's easier to reach across your body to zip up than bend your arm in strange ways from inside the bag.

Some sleeping bag zips have both an inside and an outside pull (or tag) attached to the slider (the little mechanism that 'eats' or releases the teeth). A zip with two pulls (often called a dual zipper) is ideal as it lets you open and close the bag either from the inside or the outside – and each is convenient at different times.

If you're shopping for a sleeping bag in store, check the zip yourself to censure it opens and closes smoothly.

In a winter sleeping bag, you want to have a draft tube or insulation chamber (also often called a zip baffle). This is a narrow (but often plush) strip of sleeping bag that runs along the one side of the zip and lays over it when the bag is zipped up to help to keep the warm air in and the cold air out.

A red draft tube on a First Ascent bag

Some winter sleeping bags come with both an inside and outside draft tube – this adds marginally to the weight of the bag, but can be great for better insulation.

Single-person sleeping bags come in a variety of shapes. The most common shapes are:

Here's a picture and description of each, as well as the pros and cons of each shape.

A rectangular sleeping bag gives your feet lots of room. This is a good shape for summer sleeping bags as it's nicely roomy. It can also be unzipped and laid flat like a duvet.

The classic rectangular sleeping bag

A semi-rectangular sleeping bag is a little bit tapered towards the foot box. This shape is a compromise between keeping the bag lightweight while also warm. You can still unzip a semi-rectangular sleeping bag on a hot night to lay it flat across you like a duvet.

A semi-rectangular sleeping bag

A mummy-shaped sleeping bag is widest at the shoulders and very narrow from the knees down. It's the most lightweight of the different sleeping bag shapes, and the warmest (because there's less air inside the bag to heat up). So it's a very good option for a a Himalayan trek.

The mummy-shaped sleeping bag is designed for winter conditions

Admittedly, some find a tapered foot box a touch claustrophobic. However, if you can get used to it, it's the best option for keeping your feet warm.

Most sleeping bags are branded as being unisex. Some brands, however, make mummy sleeping bags designed specifically for women. These bags are slightly narrower at the shoulders, and slightly wider by the hips.

A rare shape is one that resembles a peanut shell: it's pinched at the middle and then widens out on either side. It's made this way because the designers have the knees of side sleepers in mind.

Disco has branded their peanut shell sleeping bags as Spoon™️ bags

The peanut shell sleeping bag (this is our own name for it) has more fabric and fill than a mummy sleeping bag, and is therefore a little heavier. But for those who don't want to feel entombed in a mummy bag, or need to sleep on their side, it's ideal.

Most sleeping bag brands produce bags in a variety of sizes, both in terms of length and width. Let's look first at length.

Most brands offer their various sleeping bags in the following lengths:

You can also get kid-sized bags, of course. And some brands sell men's extra long sleeping bags.

Note that you don't want to have extra length within the bag that your feet don't reach, as that's just means more air that needs heating. A too-long bag also provides extra, unnecessary weight (but more on bag weight in a moment).

That said, a too-long sleeping bag can be useful if you want to use the extra space in the foot box to store things. In below-freezing conditions it's a good idea to put electronics in your bag to keep the batteries from being drained by the cold. And you can put a water bottle down there too so that you have water that isn't frozen to drink when you wake up.

Some brands also manufacture wide bags for broader folks. If this is you, you might like to browse REI's The Best Inclusive-Size Sleeping Bags of 2023: Tested. There are also oval-shaped sleeping bags out there that could work well, especially if you want a wider bag that also doesn't feel too restrictive in general.

Whatever your height and girth, we recommend that you shop around for a bag with dimensions that best suit your frame. If you can go into a store to try out the bags before purchasing one, that's ideal.

Most of your heat is your lost through the head.

Consequently, almost all single-person winter sleeping bags come with a hood to help keep your bonce and neck as snug as possible. Many come with a drawstring to help draw the hood in around you head and face.

A cosy hood and draft collar

A quality winter sleeping bag will also come with a draft collar (also often called a neck or shoulder baffle) that has a drawstring to help you secure it into place one you're inside the sleeping bag.

Sleeping bags are rated by 'season' to let you know their insulating properties. Each season rating designates a specific category of warmth.

You get the following sleeping bag seasons:

* The temperature range indicates the outside air temperature at which the bag can keep you warm

If you're going to be sleeping in below-freezing temperatures, like those experienced high in the Himalayas, then you want a winter sleeping bag, which is a season four or five bag.

Note that a season five sleeping bag is going to be more expensive, so you may want to go with a season four bag unless you know the conditions you'll face require a season five bag.

On the Annapurna Circuit your highest overnight elevation is 4,880 m

While the season of a sleeping bag gives you a first indication of the warmth of the bag, its temperature ratings offer more detail in this regard.

And when the temperature ratings are EN or ISO ratings, then you can know that they're ratings based on standardised testing.

EN temperature ratings were introduced in Europe at the start of the century for all sleeping bags sold in that market.

Since then the sleeping bag industry introduced ISO ratings, which replaced EN ratings moving forward and are used internationally.

ISO ratings are determined by a standardised, laboratory-based test that checks the warmth of each sleeping bag using a heated mannequin dressed in one layer of thermal clothing.

To understand a sleeping bag's temperature ratings, you need to know the terminology generally used by sleeping bag manufacturers ...

Most sleeping bags give their temperature ratings using the following terms:

Most season four sleeping bags come with a comfort rating of around -5℃ (23℉), a lower limit rating of -15℃ (5℉), and an extreme rating of -25℃ (-13℉).

Different manufacturers tend to showcase temperatures ratings differently. Just look for a tag sewn into the sleeping bag or attached to the compression sack to find the temperature ratings.

Example of a temperature rating tag

Please note that temperature ratings are geared towards the 'average' adult. If you know that you run hot or cold compared to those around you, bear this in mind when looking at a bag's temperature ratings.

Winter sleeping bags naturally weigh more than summer bags as they need more filling to keep you warm. And while you don't want to carry more weight than necessary, you need to balance looking for a lightweight sleeping bag with one that's sufficiently warm.

Down sleeping bags are lighter than synthetic ones. They can also compress smaller.

On most Nepali treks there are porters to transport your belongings if you wish

On a Nepal trek you usually have a porter to transport your overnight duffel bag for you, which can include your sleeping bag. Portering is a big source of income in many rural and underserved communities and so we encourage you to use this service if you're in doubt.

Note that different down sleeping bags come with different "down fill power". What this means is that some down sleeping bags are fluffier and therefore lighter than others.

Down fill power values usually range between 650 and 950.

A sleeping bag with a high down fill is very light, as it traps lots of air (that's the "power" part) and therefore needs fewer feathers to fill up the sleeping bag. Unsurprisingly, the higher the down fill power, the more expensive the sleeping bag!

The more insulation that a sleeping bag offers, the heavier it will be. And remember, as discussed, that synthetic sleeping bags are heavier than down sleeping bags providing the same comfort rating. Also, mummy-shaped sleeping bags are the lightest shape, with rectangle sleeping bags being the heaviest.

It's very easy these days to find a winter mummy-shaped sleeping bag with down fill that weighs below – even well below – 90 kg (2 lb).

In fact, you can get extremely lightweight down sleeping bags. The mummy-shaped, down Therm-a-Rest Hyperion 32, for instance, has a 900 fill and weighs only 450 g (1 lb)! More commonly, however, you're going to be looking at around 650 to 710 g (1 lb 7 oz to 1 lb 9 oz) for a 900-fill mummy-shaped down sleeping bag.

The North Face is one of the best brands for lightweight winter synthetic sleeping bags. Their synthetic season four Chrysalis 20 Sleeping Bag, for instance, weighs just 729 g (1 lb 9.7 oz)!

Some sleeping bags actually come with differential fill. This is where there's more fill – and thus insulation – on the top half than on the bottom half, which gets compressed under your weight.

For winter sleeping bags, where minimising their weight is important, differential fill can be a great asset. Just ensure that you pair it with a quality sleeping mat that provides excellent insulation from the cold ground.

It can be very useful to have a small pocket near the head of the sleeping bag for storing an important item or two. You might like to put your camera's batteries in the pocket, for instance, as extreme cold drains batteries.

A sleeping bag side pocket

Some sleeping bags come with a built-in pillow pocket. The name is pretty self-explanatory: the pocket lets you slip in a small pillow and then keeps it in place.

If you want to cut down on space and weight in your luggage, you could forget the pillow and simply stuff a soft piece of clothing like a fleece top into the pillow pocket.

A recent development in camping equipment is the sleeping quilt. This is essentially an open or semi-open sleeping bag.

The idea behind the development of quilts is that the part of the sleeping bag that you lie on and thus compress has little value in terms of providing warmth, so why not remove it altogether? (This is the same thinking that led to the development of differential fill in sleeping bags, as we discussed above.)

An Alsek sleeping bag quilt

A quilt is therefore designed to work in tandem with your sleeping mat (pad) to keep you warm. And it can be more lightweight than a regular sleeping bag as a result.

Quilts come in a variety of configurations. For instance, some zip up half way, and then splay open to cover your top half like a regular quilt. Another example of a quilt is one with elasticated cords that connect the two long sides of the quilt and slip snugly over your sleeping mat to keep the quilt in place on top of you.

Example of a backpacking quilt that can convert into a traditional bag

The main thing to note if you want to investigate a backpacking winter quilt is that you need to pair it with a quality, insulated sleeping mat if you're going to be camping. Your sleeping mat is all that you have (besides your clothes) keeping the floor-facing half of you warm. So ensure you choose a sleeping mat that can live up to the task!

We're not really in a position to comment on the different brands of sleeping bags out there, as we haven't conducted a review of our own of a range of bags.

What we can say is that The North Face is an excellent brand, which is why we used them to make our branded, season four Follow Alice sleeping bags. And Marco, our head of IT – who's climbed Mt Kilimanjaro, trekked to Everest Base Camp and much more – has always been very happy with his season four Western Mountaineering sleeping bag.

But if you'd like some detailed advice on particular brands that offer good-quality winter sleeping bags, you might like to read:

In many destinations around the world where trekking is a major drawcard you can often simply rent a sleeping bag.

This is true of Nepal, where there are many companies offering sleeping bag rentals. The easiest is probably renting a bag in Kathmandu, the capital city and entry point for anyone flying into Nepal.

We recommend asking your tour guide, if you have one, to suggest where to go to rent a sleeping bag, as they know the warehouses that rent quality, branded sleeping bags that are suitable for Nepal trekking. Often these are sleeping bags are secondhand, but are still in great nick and designed for the harsh conditions of trekking in the Himalayas.

Prices for hiring sleeping bags vary, but we don't recommend you opt for a bag based solely on the rental price point. Again, advice from a guide is the best route, and if they can go with you to choose one, even better!

You can also usually rent other items from these rental establishments, such as down winter jackets and gloves. Just FYI.

There are a few advantages to renting a sleeping bag, including:

A sleeping bag liner is always a good idea. We say this even if you're using your own sleeping bag. This is because a sleeping bag liner:

A mummy-shaped thermal sleeping bag liner

You can buy a sleeping bag liner or simply make one yourself using an old sheet or other large piece of material.

For arctic conditions like those you'll experience in the Himalayas, we recommend packing a thermal sleeping bag liner. This is one made from materials like polyester, nylon, fleece (a bit bulky), micro-fleece or silk (the most expensive option).

Also remember the shape of your sleeping bag when buying a sleeping bag liner. Ideally you want a liner that's the same shape as your bag.

In one sense, the only answer that's needed here is that you should follow the cleaning instructions for your particular sleeping bag! Sleeping bag manufacturers use various materials for bags' fillings and linings, so cleaning instructions will vary.

You can damage a sleeping bag if you clean it the wrong way!

Don't use too much detergent when washing your sleeping bag

For instance, a down-filled sleeping bag (which is a good option for a Nepal trek) can be hand washed or go in your washing machine, but either way you mustn't use a regular washing powder (detergent) nor a softener, as these will damage the down. You also shouldn't add too much washing detergent as this can be hard to rinse out.

Instead, you need to use a technical cleaner that's been formulated for cleaning a down bag. And never use more than what's stated. Choose a delicate cycle and keep the water temperature below 30℃. Also ensure all zips (zippers) are undone and all drawstrings are loosened as far as they'll go.

It's usually enough to launder your sleeping bag just once a year if you're diligent about always using a sleeping bag liner. Of course it also depends on how often you use your bag.

Avid trekkers should launder their bags more frequently.

Just air your sleeping bag in between washes

We advise you to give your bag a sniff now and then, and feel it for dampness, to also help you determine when it needs a wash. Most times a good airing in the sun is enough to get you bag dry in between uses and eliminate any musty odours. Sunlight is a natural disinfectant.

A good time to launder your sleeping bag is at the end of a trekking or camping season, or just before putting it away for an extended period of time. In this way you ensure any dampness or smell is eradicated before stowing it.

Your bag is also then ready for action when you next want to head out, and you don't have to remember to first clean it.

Sleeping bags with down fill lose some of their loft (fluff) after many uses. Ever used a down sleeping pillow? Then you know the issue all too well!

Loft (or fill power) refers to the space taken up by down feathers. A sleeping bag with high-quality loft is one where the feathers puff out well, thereby taking up lots of space and trapping plenty of air.

Loft is important because the trapped air helps to insulate you.

When a down bag is compressed by being slept on or stuffed into a small bag, some of that trapped air is lost over time and the bag's loft (fluffiness) is diminished.

A winter sleeping bag with good loft

To revive the loft in your down sleeping bag, try one or more of the following:

These days most sleeping bags come with a drawstring compression (stuff) sack that's a great help when transporting the bag.

Compression sacks should only be used to transport sleeping bags

But you shouldn't actually store your bag in the compression sack. Instead, you should pack it loosely inside a mesh or cotton sack.

Then, stow it in a cool, dry cupboard. And depending on where you live, consider putting a bar of soap, moth balls or whatever next to it for further protection.

Finally, in terms of your clothing, you want cosy, comfy sleeping clothes, particularly for your extremities (feet, hands and head).

View from a teahouse bedroom on the Everest Base Camp trek

Your head in particular needs a warm beanie or similar (unless your sleeping bag lets you draw the hood very snugly around your face – and you don't mind the feeling of this). The point here is that if you head is going to be somewhat exposed, a balaclava or a cosy beanie paired with a snood to pull over your mouth and nose is a must.

We also suggest using hot water bottle at night. If you're staying in a teahouse, take your bottle to the dining room to fill it up with hot water before heading to bed. Note that you should never put boiling water into a sleeping bottle, as this can damage the seams. You want to let the water cool a little and only then add it to the bottle.

And there you have it. That's our advice on how to choose a winter sleeping bag for trekking in the Himalayas of Nepal. Time to go choose an excellent, super snug sleeping bag! 🛍