Never put a waterproof jacket in the tumble dryer
The manufacturer prescribes twenty minutes in the dryer AFTER the garment is already dry, because heat is what reactivates the repellent finish.
What is claimed
That waterproof and technical outerwear must never be tumble dried, because heat damages the membrane or the coating.
Where this comes from: Widely circulated online.
Does it work?
Does not work
Refuted by the manufacturer, which prescribes the treatment the claim prohibits and gives it a purpose. The instruction is explicit, and the claim's concern about HIGH heat survives it: high temperature is excluded by the same guidance.
This is a verdict on whether the technique is effective. Whether it is safe on a particular surface is a separate question, answered below.
Where not to use it
Waterproof outerwear
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Tumble drying is specified on a warm gentle cycle, with a further 20 minutes after drying to reactivate the repellent, and high temperature is excluded. One named variant of the same product family must not be tumble dried at all.
Precautions
- Check the manufacturer's instructions
Why it works
Heat degrades many coatings and adhesives, and a laminate is bonded, so avoiding the dryer looks like the conservative choice. What it misses is that the durable water repellent is a treatment on the face fabric which is reactivated by moderate heat, so avoiding the dryer preserves the membrane and progressively abandons the repellency.
Background
Technical clothing is expensive and heat is assumed to be its enemy, so the dryer is the first thing people rule out. The manufacturer's own instruction is the opposite: once dry, tumble dry for a FURTHER 20 MINUTES to reactivate the durable water repellent treatment. The heat is not tolerated, it is the mechanism — a jacket that has started 'wetting out' has usually lost repellency rather than waterproofing, and reheating restores the finish before any re-treatment is needed. The instruction is bounded rather than open: tumble dry on a warm gentle cycle or line dry, and do not dry at a high temperature. So the claim is right about high heat and wrong about the dryer. Two qualifications keep this honest. This is one brand's specification for its own laminates. And the same page names a variant of that brand's own product where the rule reverses entirely — do not tumble dry, do not iron, do not apply repellent — which is a strong argument for the standing rule that the garment's own label outranks anything general.
What it does not do
- One brand's specification for its own membrane laminates
- The same page names a variant that must NOT be tumble dried, ironed or re-treated
- It specifies a warm gentle cycle and excludes high temperature, so the claim is correct about high heat
What to use instead
- Rinsing and drying — The step people skip, and the one that decides whether cleaning protected the surface or damaged it. Residue left behind is exposure that continues after you stop.
Evidence
Does not work
Sources
W. L. Gore & Associates (GORE-TEX brand) · Manufacturer documentation
Relied on for: That the garment is tumble dried on a warm gentle cycle or line dried, that it must not be dried at high temperature, that once dry it is tumble dried a further 20 minutes to reactivate the repellent, and that one named variant must not be tumble dried at all. (states this directly)