Conduction, which takes place when heat is transferred between solids due to vibration in molecules. Insulation products resist conductive heat transfer by trapping air or other gases in their structure, hence slowing down the motion of heat. We think your Renewal by Andersen experience is about more than just windows. https://pointedtweezers43224.blogsuperapp.com/35207859/rumored-buzz-on-soundproofing