# What is rSTUD wood?

• Asked on September 6, 2011

The R-value is a measure of thermal resistance used in the building and construction industry. Under uniform conditions it is the ratio of the temperature difference across an insulator and the heat flux (heat transfer per unit area, $\dot Q_A$) through it or $R = \Delta T/\dot Q_A$.The R-value being discussed is the unit thermal resistance. This is used for a unit value of any particular material. It is expressed as the thickness of the material divided by the thermal conductivity.