dryer taking to long to dry

My dryer does not heat as well. A couple weeks ago, it started to take longer to dry. Since we bought it new, it usually ran too hot and I dried everything on delicate - great - no shrinkages. All loads took about 35 - 55 min. to dry.

My husband replace the heating element and the thermostat that came with it. It is the same. Still takes too long to dry. As though the parts had not been replaced.

Can you tell me what we need to do?

Thank you,