More Truth About Water Proof Down

Down processors in the past year have finally added a water repellent treatment to the bath that down goes through to help it from collapsing when it gets wet. Until now they, or rather the companies that sell down sleeping bags, have kept the chemical a secret. I knew what they were doing, adding a “durable water repellent’ (DWR) chemical to the bath which is commonly referred too when applied to outerwear as DWR. Some have referred to this chemical treatment as waterproofing the down. That unfortunately does not happen to the down. The DWR will breakdown as quickly on, or from, the down as it does from your jacket. So when a down bag gets wet, the down does absorb the water and it does collapse as it did before when the chemical was not applied.

I recently read an announcement that Therm-a-rest is offering a new down technology in their women’s bags, only or so it seems. They are using a chemical that is applied to down manufactured by Nikwax. It is named “hydrophobic down”. I went to the Nikwax website and learned quite a lot about their product. Therm-a-rest states in their announcement the following: “Third-party lab reports indicate that products made with NHD (Nikwax Hydrophobic Down) absorb substantially less water.” When you read the information on the Nikwax web site they are more specific as to the deterioration of the water repellent treatment. They state the following; “Through use, the outer shell and the down fill of your down item will pick up contaminants that attract water, such as dirt and body oils from sweat. This masks the effects of any Durable Water Repellent (DWR) coating, leading to fabric and down ‘wetting out’ when exposed to moisture. (Wetting out is simply the materials absorbing the water. This term came about when the Gore-Tex laminates started absorbing water.) Therefore, your down gear could be soaking up water just because it is dirty.” Both companies agree that the down treated with the Nikwax chemical does not protect the down from absorbing water completely as has been the suggestion by the advertising and seen for the past two years from other companies advertising their bags in the outdoor industry. So the treated down does absorb water. And, the treated down does lose its water repellency. This is good for Nikwax because they also say in their online literature you will have to do two things; first wash your down bag using Nikwax Down Wash and then you will have to treat your sleeping bag with Nikwax Down Proof.

The Nikwax folk have done quite a bit of research into how well down as an insulator does not work when it gets wet. They state things such as and I quote; “When wet, down loses all of its insulating properties, as water conducts heat away from the body 25 times faster than air. It will also gain weight and its breathability will be significantly reduced; leaving you feeling cold, wet and uncomfortable”.

Now you know even more truth about the lack of performance of down sleeping bags, so why would anyone want to buy one?