Temperature conversion is not a care recommendation
Cold, warm and hot are operating choices, but the safe choice for a garment comes from its care instructions. A converter can translate units; it cannot tell whether a fabric, dye, trim or finish tolerates that temperature.
Why cold water is often useful
ENERGY STAR notes that water heating is a major share of the energy used by a clothes washer and recommends cold water for many routine loads. Cold washing can therefore reduce energy use when the garment label and cleaning task allow it.
When warmer water may be appropriate
Some soils and product directions call for warmer conditions. The safe upper limit should come from the garment care label, while detergent and stain-removal products should be used according to their own directions.
Do not translate “hotter” into “better”
More heat is not a universal cleaning upgrade. Heat can be restricted by dyes, finishes, elastic components and heat-sensitive fibers, and some stains require a cool-water first response.
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.