The use of carpet in a wall-to-wall application actually increases the R-value, or insulation level, of the carpet area, potentially saving homeowners like you utility costs while reducing energy use. The R-value (thermal resistance) measures how much a material resists the movement of heat through a ceiling, wall, or floor in a building. 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. Carpets were tested with and without cushion, and the combination maximized the R-value. Carpet really is warmer.
Test results from the different carpet constructions were compared to three hard surface products – ceramic tile, laminate, and engineered hardwood – and the differences were dramatic:
Carpet vs. engineered hardwood: From 3 to 7 times the R-value.
Carpet vs. laminate: From 4 to 8 times the R-value.
Carpet vs. ceramic tile: From 8 to 17 times the R-value.
Carpet with cushion represents a clear advantage in insulation capability over hard surface flooring. Of course, potential energy cost savings by using carpet and cushion in lieu of hard surfaces will vary widely. The type of floor construction, local energy costs, climate, and carpet/cushion type all affect how significant these savings could be.
Obviously, savings would be greater in colder regions of the country.
Dr. Alan Hedge, professor of Department of Design and Environmental Analysis at Cornell University, also cites thermal comfort as another of carpet’s advantages. “Carpet feels warmer to the touch than other floor coverings because the air at room temperature is trapped by the carpet fibers which acts as an insulator, and carpet has a low thermal diffusivity compared to other floor materials that have higher thermal diffusivities and that conduct heat away from the body more rapidly, resulting in a lower skin temperature, cooler sensation, and greater thermal discomfort,” Hedge reports.