# Definition of R-value in US English:

## R-value

### noun

• The capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power.

• ‘The next step is to compare the R-value of your insulation with the recommended R-values for your house and your type of space heating.’
• ‘Discuss the house plans with your builder, and make sure each of these spaces is insulated to the recommended R-values.’
• ‘When it comes to energy efficiency and insulation, the key issue is R-value cost per square foot.’
• ‘Manufacturers usually represent the energy efficiency of windows in terms of their U-values (conductance of heat) or their R-values (resistance to heat flow).’
• ‘You should consider the several forms of insulation available, their R-values, and the thickness needed.’
• ‘This is done by taking the R-value you would like to achieve and dividing it by the R-value per inch of the insulation material you'd like to use.’
• ‘Check with your State Energy Commission, local power company, or local home center for the optimum R-value in your region.’
• ‘Water dampens and compresses wall and attic insulation, lowering R-values and increasing heating costs.’
• ‘Thicker insulation does not necessarily mean higher R-value.’
• ‘It's more efficient to use insulation with higher R-values in the attic and in rooms with cathedral ceilings than in wood frame walls and basements or crawl spaces with walls.’
• ‘Thermal characteristics mean the R-value of the material.’
• ‘Both products offer similar R-values to other fibrous insulation types (about R - 3.5 per inch of thickness.)’
• ‘So, where R-values rate how much heat loss the material resists from passing through it, U-values rate how much heat the component allows to pass through it.’
• ‘Insulation loses its R-value as it takes on moisture.’
• ‘The R-value is the inverse of the U-value, so the higher the R-value, the more the window resists heat flow.’
• ‘For walls, this may mean looking at ways to reduce thermal bridging or increase insulation R-values.’
• ‘The cavity created by the added framing should be thick enough for the desired insulation R-value.’
• ‘Don't forget that R-values are determined by material type, thickness, and installed weight per square foot, not by thickness alone.’
• ‘For the best energy efficiency, select the proper R-value for your region, and insulate ceilings, walls and floors well.’
• ‘Also note that the R-value only refers to heat transfer per unit time and does not take into account the flywheel effect of concrete's thermal mass.’