One of the things people like about carpets as opposed to hardwood or vinyl floors is that carpet makes a room warmer. This is true both figuratively and literally. Not only does carpet make a room more inviting, but it helps insulate it. Carpet can insulate as much as 10 times more than hardwood [source: Carpet Institute].
A carpet's thermal resistance rating is known as its R-value, and this can sometimes be found on a carpet label. According to studies, the R-value of a carpet doesn't depend on the fiber type so much as its sheer thickness. If you don't see this number on the label, you can determine the approximate R-value of a carpet by multiplying its thickness (in inches) by 2.6. However, to find the total insulating value, you should include the thickness of your carpet pad in the calculation [source: CRI].
This may seem like a minor detail, but a carpet's insulating abilities could end up saving you a lot of cash. A study of elementary schools found that carpets saved them $2,000 to $8,000 in energy costs. And the Carpet Buyer's Handbook estimates that you can recoup the cost of a carpet in your home in 9 years [source: Cooper].