R-value

[ ahr-val-yoo ]

noun

1. a measure of the resistance of an insulating or building material to heat flow, expressed as R-11, R-20, and so on; the higher the number, the greater the resistance to heat flow.

Word History and Origins

Origin of R-value¹

1945–50; R, symbol for resistance

Example Sentences

Your insulation’s effectiveness is measured in thermal resistance, otherwise known as R-value.

From Seattle Times

The ideal R-value for your home depends on what kind of space you’re insulation and the climate you live in.

From Seattle Times

Make sure your pro provides a fact sheet that explains the R-value of your materials.

From Seattle Times

Most home insulation is rated between R13 and R60, with the highest R-value usually reserved for the attic.

From Seattle Times

A higher R-value means the insulation is better at slowing down heat.

From Seattle Times