I'm not an expert with this stuff, but I found this e-mail from gore-tex in another forum:
First of all, we recommend following the manufacturer's instructions as the
best way to care for the garment.
Generally, washing the garment in the washing machine, using regular laundry
detergent, and then drying it in the dryer, on low to medium heat for about
hour, is the best way to care for your GORE-TEX® garment. The heat from the
dryer actually helps to "revive" the Durable Water Repellent (DWR) that is
coated to the outside shell of the garment. The GORE-TEX® membrane is
laminated to the inside of the outside shell, providing a waterproof
barrier. The heat from the dryer does not affect the membrane in anyway.
Higher heat may affect the outside shell of the product, but again, please
contact the manufacturer for this information. Also, ironing the garment
using low heat adds a nice finishing touch that helps enhance the
effectiveness of the repellency.
What does happen when a garment is not cared for on a regular basis, is that
the DWR becomes "masked" and then does not perform properly. The outside
shell becomes saturated (called wet out) and this prevents the water vapors
that are coming off your body from "escaping" to the outside
(breathability). The garment becomes heavy and water logged, and then you
begin to feel cold and damp on the inside. In fact, it might feel like the
garment is actually leaking from the condensation that is occurring. So it
is best to keep the DWR at its peak performance.
Ask your local "Outdoor Retailer" to show you a "Durable Water Repellent"
(DWR) for Waterproof/Breathable Fabrics.
W. L. Gore & Associates, Inc does not recommend or endorse any one name
brand over another. However, some examples would be:
NOTE: W. L. Gore & Associates, Inc, does not recommend the use of "wash-in"
DWR restoration products for garment with "high performance/wicking liners.
However, DWR does not need to be applied to the garment each time, and if
you are still getting wet on the inside after applying the DWR then there
may be a problem with the GORE-TEX® membrane (the waterproof membrane.) If
this is the case, please call me at the number below so we can discuss your
Please let me know if I can be of any further assistance.
W. L. Gore & Associates, Inc
Fabrics Consumer Advocate Team
1 800 GORE-TEX (467 3839)www.gore-tex.com