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Installed faced fiberglass batt insulation with its R-value visible (R-21) [1]. The R-value (in K⋅m 2 /W) is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive [2] flow of heat, in the context of construction. [3]
This is a list of insulation materials used around the world. Typical R-values are given for various materials and structures as approximations based on the average of available figures and are sorted by lowest value. R-value at 1 m gives R-values normalised to a 1 metre (3 ft 3 in) thickness and sorts by median value of the range.
More expensive than most other types of insulation. Some types may be susceptible to termites using them for nesting purposes. May have R-values higher than that of still air, if some type of insulating gas was blown into them during manufacturing. For many years, manufacturers used chlorofluorocarbons (CFCs) or urea-formaldehyde as blowing ...
The passivhaus standard combines superinsulation with other techniques and technologies to achieve ultra-low energy use.. Superinsulation is an approach to building design, construction, and retrofitting that dramatically reduces heat loss (and gain) by using much higher insulation levels and airtightness than average.
The effectiveness of bulk insulation is commonly evaluated by its R-value, of which there are two – metric (SI) (with unit K⋅W −1 ⋅m 2) and US customary (with unit °F⋅ft 2 ⋅h/BTU), the former being 0.176 times the latter numerically, or the reciprocal quantity the thermal conductivity or U-value W⋅K −1 ⋅m −2.
R-value is the term given to thermal resistance to heat flow. The higher the R-value of an insulation product, the more effective the insulation properties. Spray polyurethane foam comes in a range of densities and cell structure. Low density foams are referred to as open cell SPF while higher density foams are referred to as closed cell foam.
The construction industry makes use of measures such as the R-value (resistance) and the U-value (transmittance or conductance). Although related to the thermal conductivity of a material used in an insulation product or assembly, R- and U-values are measured per unit area, and depend on the specified thickness of the product or assembly. [note 2]
R-value is a measure of apparent thermal conductivity, and thus describes the rate that heat energy is conducted through a material or assembly, regardless of its original source. The higher the R-value, the slower at which heat energy is conducted. It describes the rate of heat transfer and not the total amount that is transferred.