Curling tip 2: Choose the right heat for your hair Second, know how hot to go. Your hair type should determine your heat setting, and you'll need an iron with variable heat settings in order to control it (so look for that feature at time of purchase). If your hair is fine, fragile or color treated, use a low heat setting -- below 200 degrees -- to avoid burning or damaging your hair. If you have already curly, coarse or thick hair, you can go higher -- between 200-300 degrees, says Moticka. As you curl your hair, notice how it responds to the heat and increase the temperature accordingly. Never go above 400 degrees though, she warns.