A zip-up hoodie has hard parts, a zip and sometimes metal tips on drawcords, that rub against the soft parts and other items in a wash load. The required care instruction covers temperature, cycle and drying, as the FTC Care Labeling Rule in 16 CFR Part 423 describes, but it does not say how to handle the zip. Whether to add advice depends on what your own tests show.

What can go wrong

With the zip open, the teeth can snag fleece or other garments in the load, and the sides of the zip tape can twist or stretch. With the zip closed, tension on the tape from agitation can distort a front where the tape shrinks differently from the body fabric. Metal zips can scratch prints on the same garment or others. Drawcord tips can also catch.

Test both ways

Wash sample hoodies with a named procedure such as ISO 6330 using the programme in your label, and run each for the target number of cycles with the zip open and with it closed, with and without a mixed load. Compare the front for waves and puckering, and the fleece and prints for snags and scratches. Check that the zip still runs smoothly; ASTM D2061 describes strength tests for zippers if you need to check that function after washing.

Choose the advice

If closing the zip helps and does no harm, say so in plain words, for example next to the wash instruction. If turning the hoodie inside out protects the print, say that. Keep any extra advice consistent with the temperature and drying instruction, and make sure the advice is something you actually tested.

Fix the cause where you can

If the front waves after washing, the tape and fabric shrink differently, so the better fix is a tape that matches the fabric. If snagging is common, a fabric with a less open surface or a zipper garage that covers the top of the slider may help more than a label.

Keep records

Store the test photos with the style and repeat the test if you change the zip, the tape or the fabric.