The use of carpet in a wall-to-wall application actually increases the R-value of the carpet area, potentially saving homeowners money while reducing energy use. The R-value measures how much a material resists the movement of heat through a ceiling, wall, or floor. The higher the number, the more effective the insulation.
Recently, tests carried out at the Johns Manville Technical Center Thermal Labs, one of the most sophisticated laboratories of its kind in the world, confirm carpet and pad significantly increase R-value compared to other flooring materials. Results varied according to the carpet's construction, with heavier products generally providing higher R-value. Shaw carpets were tested with and without cushion, and the combination maximized the R-value.
Carpet really is warmer.