R-value

American

[ahr-val-yoo] / ˈɑrˌvæl yu /

noun

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.

Etymology

Origin of R-value

1945–50; R, symbol for resistance

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

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

From Seattle Times • Dec. 5, 2023

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

From Seattle Times • Dec. 5, 2023

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

From Seattle Times • Dec. 5, 2023

The price for closed-cell foam that’s the exact same R-value as the fiberglass is $12,410.

From Seattle Times • Feb. 6, 2023

From an energy-saving perspective, it doesn’t matter, as long as you install the depth recommended on the package to bring the total insulation to the R-value needed where you live.

From Washington Post • Nov. 23, 2021

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023