In the domain dashboard, go to the Advanced DNS panel, and add an A+ Dynamic DNS Record, entering the name for your dynamic host e.g. “homepc” and enter any dummy filter for the IP address e.g. 127.0.0.1
Still within the Advanced DNS panel, scroll down and enable the Dynamic DNS. Make a copy of the Dynamic DNS Password.
Setup script on the host PC
Create a batch file that will update your dynamic host IP address to the Namecheap DNS servers, automatically using the IP address the request comes from: