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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.
DuPont produces Styrofoam building materials, including varieties of building insulation sheathing and pipe insulation. The claimed R-value of Styrofoam insulation is approximately 5 °F⋅ft 2 ⋅h/BTU for 1 inch thick sheet. [7] Styrofoam can be used under roads and other structures to prevent soil disturbances due to freezing and thawing. [8 ...
Closed-cell foams are superior insulators. While open-cell foams typically have R-values of 3 to 4 per inch (RSI-0.53 to RSI-0.70 per inch), closed-cell foams can attain R-values of 5 to 8 per inch (RSI-0.88 to RSI-1.41 per inch). This is important if space is limited, because it allows a thinner layer of insulation to be used.
A multi-family residential building under construction with rigid panel exterior insulating sheathing. Rigid panel insulation, also referred to as continuous insulation, [1] can be made from foam plastics such as polyurethane (PUR), polyisocyanurate (PIR), and polystyrene, or from fibrous materials such as fiberglass, rock and slag wool.
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.
Once airtightness is achieved, it has often been sufficient to choose the thickness of the insulating layer based on rules of thumb. Diminishing returns are achieved with each successive doubling of the insulating layer. It can be shown that for some systems, there is a minimum insulation thickness required for an improvement to be realized. [8]
The reported R-value ranges from 17–55 (in American units) or 3–9.6 (in SI) depending on the study, differing wall designs could be responsible for wide range in R-value. [ 33 ] [ 34 ] given that the bales are over a foot thick, the R-value per inch is lower than most other commercial insulation types including batts (3–4) and foamboard (~5).