Begin with the drying instruction
The FTC Care Labeling Rule treats drying as part of regular garment care. If the label specifies line dry, dry flat, tumble dry low or another method, that instruction should control the decision.
Why air drying can help
ENERGY STAR recommends air drying when practical as a way to save energy. Avoiding heated tumble drying can also reduce heat exposure for items whose construction is sensitive to high temperatures.
Why tumble drying can be useful
A dryer is fast and convenient when the garment label permits it. Use the specified temperature and cycle, and avoid assuming high heat is acceptable when the label gives a lower limit.
Shape matters for some items
Knitwear and other shape-sensitive items may call for flat drying or reshaping. Hanging a heavy wet knit can stretch it, so follow the product-specific drying instruction rather than a generic “air dry” rule.
Garment care labels, appliance manuals and laundry-product directions can be more specific than a general guide. Use them when they set a tighter limit.