Above all, consider the insulating power of the down used in the jacket. Fill power refers to the size of air that one ounce of down occupies, and it's measured in square inches. Higher fill power down is generally more expensive, but it also provides better insulation and weight savings. Look for jackets with a fill power of at least 800, but ideally 1000 or greater.

Another important consideration is the type of down used in the jacket. Down from geese is generally considered to be of higher quality than duck down, as it's gently and more insulating. However, goose down is also more costly, and it can be more susceptible to bacterial growth, which can affect its insulating properties. Duck down, on the other hand, is more inexpensive, but it may not be as gentle or cozy as goose down.

It's also essential to consider the outer layer material and its water-repellent rating. A water-repellent shell will help to extend the life of the down by preventing moisture from seeping in and reducing its insulating capacity. Look for インナーダウン おすすめ jackets with a shell made from a water-repellent material such as nylon, and a water-repellency rating of at least 10,000 mm.

Moreover the down and shell, the construction and adjustment of the jacket are also essential. Look for jackets with a closed construction to prevent cold air from entering and warm air from escaping. A well-fitted jacket is also essential to prevent cold air from entering through gaps between the fit and your body. Consider a jacket with closable cuffs, hem, and hood to customize the fit to your needs.

Care is also an vital consideration when it comes to down filled jackets. Down can lose its insulating properties if it becomes wet, so it's vital to air down filled jackets thoroughly after washing. Look for jackets with drying instructions, and avoid washing them in warm water or using fabric softener, which can damage the down and affect its insulating properties.

Ultimately, consider your planned use for the jacket. If you plan to wear the jacket for high-intensity activities such as climbing or skiing, you'll need a jacket with a DWR finish to prevent moisture from seeping in. If you plan to use the jacket for everyday activities, a less casual jacket with a simpler design may be enough.

In the end, choosing the right down filled jacket involves considering several factors, including fill power, down type, shell material, build, fit, and maintenance requirements. By considering these factors and selecting a high-quality jacket, you'll be able to enjoy the warmth and comfort of a down filled jacket for years to come.