Look up: R-value

1. R factor or value
   - A measure of a materials resistance to the passage of heat. New homewalls are usually insulated with 4' of batt insulation with an R value of R-13, and a ceiling insulation of R-30.
   Found on http://www.homebuildingmanual.com/Glossa
   
   
2. R Value
   A measure of insulation. For example, typical new home's walls are usually insulated with 6' of batt insulation with an R value of R-19, and a ceiling insulation of R-28.
   Found on http://www.soundhome.com/glossary
   
   
3. R-Value
   A unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher the R-value number, a material, the greater its insulating properties and the slower the heat flow through it. The s...
   Found on http://www.neo.ne.gov/statshtml/glossary
   
   
4. R-Value
   Resistance to thermal transfer or heat flow. Higher R-value numbers indicate greater insulating value.
   Found on http://www.encyclo.co.uk/visitor-contrib
   
   
5. R-VALUE
   The thermal resistance of a glazing system. The R-value is the reciprocal of the U-value. The higher the R value, the less heat is transmitted throughout the glazing material.
   Found on http://www.proofrock.com/construction_te
   
   
6. R-Value
   A measure of the capacity of a material to resist heat transfer. The R-Value is the reciprocal of the conductivity of a material (U-Value). The larger the R-Value of a material, the greater its insulating properties.
   Found on http://www.electromn.com/glossary/r.htm
   
   
7. R-value
   The measure of insulating capability, 3-1/2
   Found on http://www.modspace.com/resources/glossa
   
   
8. R-value
   (insulation) is an extremely efficient man-made insulator and has a very high R-value. 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 ...
   Found on http://en.wikipedia.org/wiki/R-value
   
   
9. R-value
   (soils) The `R-Value` test, http://www.dot.ca.gov/hq/esc/ctms/pdf/CT_301.pdf California Test 301, measures the response of a compacted sample of soil or aggregate to a vertically applied pressure under specific conditions. This test is used by Caltrans for pavement design, replacing the Calif...
   Found on http://en.wikipedia.org/wiki/R-value