When upgrading our SharePoint 2013 environment to the June 2014 update we noted installation times in excess of four hours, so when it came to the September update we looked into how we could (if possible) reduce the installaion and deployment time.
I came across the following technet post which reduced installation time significantly on our farms: http://blogs.msdn.com/b/russmax/archive/2013/04/01/why-sharepoint-2013-cumulative-update-takes-5-hours-to-install.aspx