Do you know why people use sleeping bag liners?

You may think that they serve primarily for extra warmth, but surprisingly that’s not true.

It turns out that their main objective is keeping your sleeping bag free from body oils. This allows you to wash your sleeping bag less frequently, which means it will last much longer.

The extra insulation is just a benefit that comes along.

But the thing is, silk is one of the least insulating fabrics used in sleeping bag liners, so why would anyone prefer silk over more insulating fabrics?

I already wrote a brief answer to that question:

Silk sleeping bag liners are worth it if you need a light and compact liner to keep your sleeping bag clean. But if you need a liner for cold-weather camping trips, then it’s best to look into synthetic fabrics.

Now, let’s have a look at the advantages of a silk sleeping bag liner.

The Pros Of Silk Sleeping Bag Liners

Silk liners may not be victorious in retaining heat, but they do a good job in the following:

• Weight: Silk is a thin and light fabric, often a few ounces lighter than its competitors.
• Packed size: Because silk is so thin, it packs very small and can be easily carried around.
• Breathability: Silk is breathable, quick-drying and good at wicking away moisture.
• Softness: Silk features a luxurious and soft feeling to sleep in.
• Naturally antimicrobial: Unlike synthetic fabrics, silk doesn’t stink easily due to its natural antimicrobial properties.

These benefits make silk a popular fabric among backpackers in warm conditions.

Unfortunately, a lack of heat retention is not the only downside of a silk sleeping bag liner…

The Cons Of Silk Sleeping Bag Liners

Besides their poor insulating qualities, you should consider the following:

• Silk is expensive: It shows a significant price difference from its alternatives.
• Silk is delicate: Machine washing silk is not recommended unless you have a delicate/silk cycle and use a low temperature. I advise you to hand wash your silk liner to make it last longer.
• Silk is vulnerable to UV: Avoid drying your silk liner in direct sunlight because prolonged UV exposure damages the fabric. It weakens the threads, increasing the likelihood of tears (if you’re worried about tears, choose a liner made of ripstop silk).
• Silk is not animal-friendly: Maybe you think it’s important not to buy animal products. I respect that. You should know that a silk liner is made at the expense of many silkworms’ lives.

But perhaps the biggest drawback of silk sleeping bag liners is that you can’t use them on cold weather camping trips. Not because it would be too cold, but because it would compromise your sleeping bag.

Why You Can’t Use a Silk Sleeping Bag Liner In Freezing Temperatures

You sweat and exhale approximately 7 ounces of moisture per eight hours of sleep. This moisture goes straight into your liner and sleeping bag.

This isn’t a problem in warm conditions because you can dry it the next day. But during the winter, that moisture stays inside your sleeping bag and wets your bag’s insulation.

While this is nothing to worry about if you’re only camping for one night, the longer you camp for, the more moisture builds up in your sleeping bag and the colder you get.

So if it’s too cold to dry anything out during the day, it only makes sense that you prevent water from getting in.

The problem with a silk liner is that it’s too breathable and moisture-wicking to use in the winter. It just passes your sweat on to your sleeping bag.

But don’t worry. There’s a solution.

A vapor barrier liner (VBL) does the exact opposite of a silk liner. It forms a barrier to moisture and adds extra warmth despite its thin fabric. It’s an essential item for anyone who likes to winterize beyond the weekend.

Tip: since vapor barrier liners can easily overheat you, make sure your tent is well ventilated and that you’re wearing a thin, wicking baselayer. If you’re still sweating excessively, it means that your sleeping bag is too insulated.

Let’s Wrap Things Up

So what did you learn today?

• Silk sleeping bag liners are worth your money if you’re camping in warm conditions, although your budget plays a role.
• Their packability and lightness make them the favorite choice among many backpackers.

As for the best silk sleeping bag liner, I would recommend the most popular one, which is the Cocoon Silk Mummy Liner, although there are many more great options to choose from.