Does polyester shrink when it's washed and dried?

Yes. Heat can cause the fabric to shrink in a small amount if it is kept in the dryer/washer for too long. If you are worried about your polyester fabrics, follow these simple steps:

1. Wash the polyester inside out. Aside from shrinkage, polyester can snag easily if caught on clasps, trim, or zippers when in the washer/dryer.
2. Use warm water and standard detergent when washing polyester. Cold water may not effectively remove stains from polyester, especially oil-based stains. Avoid using hot water as it may cause minor shrinkage and color bleeding. Add some fabric softener to the load to reduce static cling.
3. Dry polyester garments in the dryer using a low temperature. Polyester garments that dry too long or at too hot of a setting may shrink. Polyester dries quickly and maintains shape if taken care of properly (Air drying also recommended). If you chose to air dry your polyester, keep the fabric out of the sun to avoid color change or a faded look.
4. Soak white garments overnight in a mixture of 1 gal. (3.9 L) of warm water and 1/2 cup of automatic dishwasher detergent. Dishwasher detergent helps brighten the whiteness of clothing - bleach may be too harsh for the fabric.
5. Hand-wash polyester garments in order to thoroughly clean them. Swirl your clothing around in warm water and then rinse them with clean water. To dry your clothing, fold them and press them against the basin side to squeeze out excess water. Items that are stained should be machine washed to ensure stain removal.