Roof Insulation R Value Chart

For example a wall with 3 fiberglass batting r value of 10 8 11 9 may have an overall r value of nearly 14 because of siding sheathing and drywall.

Roof insulation r value chart.

Thickness inches r value in i p imperial rsi r value in metric 0 5. Rsi r value système international is the metric equivalent. Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces. To convert rsi to r value multiply the rsi by 5 67826.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. R value of various materials. Recommended home insulation r values. See the department of energy s doe ranges for recommended levels of insulation below.

To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. You should of course see the manufacturer provided technical data sheet for the r value of specific products. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1.

I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. R value chart for enerfoil tm rigid foam faced insulation. For a very good introductory overview article on r value see r values over at the website of. R value insulation chart find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.

The increase r21 r3 exactly 18 the value by which you are increasing the r value. The table below shows what levels of insulation are cost effective for different climates and. Insulation level are specified by r value. As a benchmark one inch of solid wood has an r value of 1.

Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value. The percentage increase increase increase original number 100. The higher the r value the better the thermal performance of the insulation. R value is used in the united states.

R value is a measure of insulation s ability to resist heat traveling through it. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7.