Difference between R values and U values?

User: Corinthians
Posts 50

There are two big differences. The first difference is that R-value is used to rate the energy efficiency of a single component, while U-values rate the energy efficiency of the combined materials in a building component or section. Secondly, while R-values rate how much heat loss the material resists from passing through it, U-values rate how much the heat the component allows to pass through it. So, a high R-value indicates good energy efficiency - and a low U-value indicates good energy efficiency.

User: mike
Posts 50

The conversion formula is simple R = 1/U and U =1/R.

User: kimchi
Posts 50

R-values rate heat loss resistance and U-values rate actual heat loss.

User: peter
Posts 50

I know they are both used for energy efficiency, but what is the difference between R values and U values for glass windows? How high a rating do you need if you live in Miami?