You are heading to Mount Kilimanjaro soon. As you sort out your gear, you ask yourself “Will my jacket be warm enough?”; “Should I buy a new one or should I just rent one from Peak Planet?”; “Down vs. synthetic jacket?”

The answer to these questions is a little more complicated than you may think. The easy answer is to rent one from us. See here:

If, however, you really like jackets. And who can blame you? They are awesome. Then what should you look for in a jacket?

The first thing you need to decide is if you want down or synthetic. Some people are allergic to down so that makes the choice for them. However, if you are not allergic, then how to choose the right jacket for Kilimanjaro?

down vs synthetic KilimanjaroDown

When choosing down an area that is often overlooked is the fill power and the fill weight. These differences are crucial to your warmth-to-weight and down-to-feather ratios.

What is Down?

Down comes from the feathers of birds. It is the soft fluffy feathers that keep the bird warm. The down we use comes from ducks and geese. The more mature the bird, the greater the loft and higher down fill power rating.

So why do we use down? Down insulates really well at a low weight. During manufacturing, the down gets formed into clusters., These clusters are used for pillows, comforters, sleeping bags, and jackets. Each cluster is made up of tiny fibers that allow air to loft between them. Similar to a sponge and water. These pockets absorb air, allowing it to heat up while allowing the material to breathe.

Another benefit to down is that you can pack it very small and despite the compression, it resists damage. This is why down is widely considered to be the best insulator known to man. Down jackets keep you comfortably warm without weighing you down.

There are three things to consider when purchasing a down insulated product: weight, fill power, and ratio. Below we will cover all three properties of down.

patagonia jacket

Patagonia Jacket

Fill Weight

The weight of down is just that—weight. The weight of down in a jacket is the quantity of down. Say, for example, a jacket has a weight of 10 ounces. That means 10 ounces of down was used to make it.

Many manufacturers show their fill power and fail to mention their fill weight. Nevertheless, fill weight is equally important to how warm a jacket will keep you.

Patagonia gets the question, “How much down is in that jacket?” so often they have written a post about it:

Fill Power

Comparatively, fill power measures the loft of a down product. Maximum loft occurs when the down is fully expanded. For example, an 800 fill power jacket means that one ounce of down can cover 800 cubic inches. Keep in mind that the measurement changes from the United States to Europe. Generally, the fill power rating ranges from 300 to 900 and above. The most common down products have a rating of 400 to 500. These are considered to be low quality, however, as they come from immature geese and ducks and therefore are made from smaller down clusters. When purchasing a high quality down fill jacket, you should look for a fill power rating of at least 600. A jacket of this caliber will be both warmer and more comfortable. We recommend at least an 800 fill power down jacket for Kilimanjaro. Of course, you’ll also want to dress in layers to make sure you are warm enough.

down vs feather

Feather and Down

Down-to-Feather Ratio

Lastly, you should look for the down-to-feather ratio of a jacket. The numbers are generally listed as 70/30, 80/20 or 90/10. The first number is the percentage of down whereas the second is the percentage of feathers. The higher the first number the better the quality. For example, an 800 fill power down jacket with a down to feather ratio of 90/10 will keep you warmer than one at 70/30.

Water-Resistant Down

In addition to regular down, there is also water-resistant down. The benefit of water-resistant down is that it packs down small, is ultralight and ultra warm. However, we do not recommend it since it costs more and the performance you get from it when wet is not as good as a good synthetic jacket.

Hybrid Down/Synthetic Insulation

Another option is the down/synthetic combination jackets. By mixing the two, you get both warmth and performance. This is a less expensive alternative to a down jacket.

How to care for your down jacket

You decided on the down jacket. But you want it to last for many years. Below are tips on how to keep it performing well for a long time.


  • Machine-wash your down jacket on a gentle cycle on warm. If available, select the “extra rinse” option. Use a down-specific soap or detergent, like Granger’s Downwash.
  • Skip the spin cycle. It’s better for your jacket to drip dry.


  • Soak your down jacket for approximately 60 minutes in a down-specific detergent.
  • Rinse by lightly squeezing out as much water as possible. Do not wring it.


  • Once you are done washing the jacket, lay it flat on a clothing rack. As you do this, gently fluff up the down.
  • It can take 24–48 hours to drip dry depending on the weather conditions.
  • As it dries, keep giving it the occasional fluff, particularly around any wet clumps of down.
  • When the jacket is almost dry, put it in the dryer on a low heat and check it regularly.
  • To maximize the loft of your down jacket, throw in two to three tennis balls, to help fluff up the down.

Things to avoid:

Down works great in the cold, but when wet, it will need a little extra attention from you. To ensure you don’t damage your jacket, here’s what you should avoid:

  • Fabric softener – stick to a down-specific detergent for the best results.
  • Dry cleaning – the solvents they use in the dry cleaning process can damage your jacket.
  • A top loading washer with an agitator – agitators create a rougher wash cycle.
  • The spin cycle – down is heavy when it’s wet, be careful not to damage it.
  • Wringing – don’t wring your jacket, no matter how heavy it is. If you must, gently shake any excess water off while supporting the weight of the jacket.
  • Wearing or storing your down jacket while it’s wet.

Synthetic jackets

So what if you are allergic to down or want an alternative? Then choose synthetic. Synthetic jacket technology has come a long way. They are available in a vast range of branded technologies. All synthetics use some form of compressible water-repellent fibers. Innovation is rapid and the performance gap with down is shrinking. Insulation can anything from Primaloft to recycled water bottles.

One thing to keep in mind is that the puffiness of a jacket is not indicative of its warmth. Superfine fibers are both slim and warming. One of the main reasons to go with synthetic jackets is that they perform well in damp environments. They also dry faster than down. Furthermore, they tend to be less expensive than down.

The drawback to using synthetic is that they are heavier, less durable, and do not pack down as small.

Hopefully, this will make it easier for you to make sense of all the numbers you see when purchasing a jacket for Kilimanjaro. Remember, it’s important to pay attention to all of the aspects of the jacket.

And lastly, if you are sensitive to being cold, then you must plan well. Make sure you follow the suggestions on layering given in this video:

It’s important to be safe while on Kilimanjaro. Now you’ll be able to informatively choose a high-quality down or synthetic jacket to protect you from the elements and keep you comfortable longer. Stay warm, and keep adventuring.

Recommended Posts

Start typing and press Enter to search