Floor coverings play an important role in thermal insulation.

(Source:http://www.milieucentraal.nl/onderwerp/set?onderwerp=Vloerbedekking&onderdeel=Tapijt#Tapij)

Reduced heat dissipation

This illustration shows that carpet reduces the heat flow through the floor by
acting as an insulator.

(Source: Dr. Lothar Siebel, Sachverständiger für Bauphysik, Aachen)