In Vivado 2014.1 and later versions, the Vivado Design Suite installer has an option to "Install from a previously downloaded archive"
What is this? Why is it useful? How do I do it?
Installing from a previously downloaded archive
This feature allows you to install Vivado Design Suite without downloading the installation files again.
In order to use this feature, you will need to have access through the file system to a DVD or an extracted .tar.gz of the full product installation image.
After selecting the option to "Install from a previously downloaded archive", specify the root directory of the full image and click next.