The importance of the "Fill Power" of your sleeping bag

Every hiker is looking to maximize their warmth, while minimizing the weight of their sleeping bag. Down quality accounts for 90% of the possible weight reduction of a sleeping bag 🙂

That's why it's important to understand the value of fill power and compare it when buying a sleeping bag.

It's simple, the higher the fill power, the higher the temperature to weight ratio.

Here is an example:

As hikers, we also want our sleeping bag to take up as little space as possible in our backpack.

The higher the fill power, the greater the compression of the feather. In other words, a high fill power will ensure that your sleeping bag will take up less space in your hiking bag.

Here is an example:

The price of your sleeping bag is directly related to the value of your fill power. The higher the fill power, the higher the price of the feather.

Down sleeping bag prices can vary from $100 to $650 for the same temperature.

When you look at the product data sheet, you will see significant differences in weight, fill power and compression volume.

Example of a regular 3 seasons sleeping bag -4°C / 10°F

To increase moisture resistance, many companies treat their down. This water repellent (water resistant) treatment allows for less impact of moisture on your feather 🙂

As hikers, we also want our sleeping bag to take up as little space as possible in our backpack.

The higher the fill power, the greater the compression of the feather. In other words, a high fill power will ensure that your sleeping bag will take up less space in your hiking bag.

Here is an example:

Yes and No. 😝

Low quality companies

The temperatures of these companies should not be trusted at all. Their goal is to sell at low prices with poor quality.

These sleeping bags are good for sleeping in a heated cabin, but not for hiking. You have to be very careful!

Large companies

You can rely on the temperature values.

Specialized companies

You can rely on the temperature values.

Unlike large companies, specialized companies each have their own internal policy. There are some differences between specialized companies and large companies.

Politicians tend towards a normalization of these values. You can trust them!

The European standard ISO 23537

There is a European norm ISO 23537 to standardize the temperature of sleeping bags. Today, this standard is not used much in the industry. We will watch its evolution!

→ We recommend comparing two sleeping bags yourself to make sure you make the right choice.

In order to compare two sleeping bags, the following ratio must be compared:

👉 Key ratio = Feather weight / Total area.

This ratio will allow you to calculate the number of oz / sqyd or gr / sqyd. Each company uses a different ratio according to its standards.

Note that you need to compare two sleeping bags with the same fill power. In order to know the surface area of the sleeping bag, you can use approximations from the shape of the sleeping bag 🙂