It heats up right away in just a few minutes. It can heat up to 450 f to help those who have think or wavy hair. This hair brush iron has a auto shut of for safety and its a smooth tough. There is a nice size screen that lights up to easily read the temp and settings. On the side of the iron there is a + and – buttons if you push both at the same time it well change from Centigrade to Fahrenheit. I have wavy hair and always try to straighten it with a hair dryer or a flat iron but it really seems to never work out right for me. Now I was asked to test this hair straightener brush and wow it does a awesome job. It is so easy to use and to set. It has 3 in 1 functions a Straightener/ De-tangling Brush / Anion Hair Massager. Use can use hair treatment oils on the brush iron to message your head and hair for better looking hair. The cord on the iron also can move so it does not get all twisted up on you. This brush iron works great and very good quality. I love it and happy I was able to test and review this iron. I am more then happy with it .