Choosing a Down Jacket
Down is still the number one insulating material in the outdoor industry, offering the lightest warmth to weight ratio and unrivaled packability. Therefore, a down jacket will provide exceptional warmth but won't weigh you or your pack down. Choosing a down jacket depends on how warm you need it to be and what features you need it to have.
HOW WARM SHOULD IT BE?
Our lightest down jackets weigh less than 150 grams and will be as warm as a microfleece that is three times the weight. Heavier down jackets around 350-500 grams are equivalent to very heavyweight fleeces in terms of warmth and are ideal mid layers. Beyond this weight there are jackets weighing 500 grams + which are outer garments for very cold conditions. Therefore, when comparing the warmth of jackets, there are some factors to consider.
Generally the more down in a jacket (fill weight), the warmer it is going to be but this assumes the down is the same quality. However, down quality can vary significantly and is measured by its fill power. A higher fill power down will keep you warmer than a lower fill power. To make matters worse there are two widely recognised methods of measuring Fill Power - the 'US' Method and the 'EU' Method. Both methods work on the same methodology but the 'US' Method gives a slightly higher figure than the 'EU' Method for the same quality down - so an 800+ Fill Power (EU Method) is approximately equivalent to an 850+ Fill Power (US Method).
Wherever we quote a Fill Power for a specific garment (or sleeping bag) we specify that the measurement is either 'EU' or 'US' method - so that you can be sure of the facts. Because the difference is small, and for simplicity, when writing in general - such as for this article - we won't make the distinction. So, as a general rule then:
650 fill power is considered to be a high quality down for outdoor gear.
750-850 fill power is considered to be in the upper bracket in terms of down quality.
900+ fill power is even higher quality again but is expensive, resulting in higher priced garments.
TIPS & CARE
STORING YOUR DOWN JACKET
If you're putting your down jacket away for an extended period of time i.e. throughout summer, it should be hung up so that the down isn't compressed, as this can damage the fill of the down and where it is stored should also be dry. Down jackets should not be stored in their compression sacks for long periods of time.
To summarise, down jackets are great for cold conditions and they are the pinnacle of insulation when it comes to warmth-to-weight ratio compared to other alternatives, such as synthetic insulation. When choosing a down jacket, there are a number of points to take in to account, which have been outlined above but how warm you need to jacket to be and whether you will be using it as a mid or outer-layer should be the two main considerations.