R-value
Insulation efficiency rating
An R-value is a measure of thermal resistance in insulation and building materials.
The higher the R-value, the better the material resists heat transfer: We need R-30 insulation for the ceiling.
Building codes specify minimum R-values for walls, floors, and attics based on climate zones.
In programming contexts, R-value refers to an expression that yields a value but cannot be assigned to—it appears on the right side of an assignment statement. (Also written r-value.)
Pertaining to warmth
- conductivityAbility to carry current
- fiberglassReinforced woven strand composite
- cellulosePlant wall polysaccharide
- foamBubble-filled substance
batt · wall · attic · temperature · barrier · BTU · thickness · density
thermal
Pertaining to warmth
- conductivityAbility to carry current
- fiberglassReinforced woven strand composite
- cellulosePlant wall polysaccharide
foam · batt · wall · attic · temperature · barrier · BTU · thickness · density · envelope
expression
Conveyed thought or feeling
- assignmentAllocated work or duty
- temporaryLimited in duration
- heatheat transfer, thermal energy, heatwave, radiation, convection
- unitsunit, angstrom, yard, meter, base units
- heat retentioninsulation, thermal mass, double glazing, thermos, wetsuit
- insulationfiberglass, mineral wool, foam, cellulose, rock wool
- energy ratingsA rating, G rating, star rating, one star, two star
- heat transferconduction, convection, heat flow, heat transfer, conductors
R-valuethermal bridging
Conductive bypass through insulation