It depends on the simplicol dye series that you have selected and the maximum temperature at which your textile can be washed.
With the Textile Dye intensive and the Back-to… products, dyeing is done at 40°C.
With the Textile Dye expert, dyeing is done at 60°C.
Exceptions: wool and machine-washable silk can be treated against the manufacturer’s advice at 60°C. However, they must be dyed in a pot, not in the washing machine.