Roof Insulation R Value Chart

Recommended home insulation r values.

Roof insulation r value chart.

Rsi r value système international is the metric equivalent. The increase r21 r3 exactly 18 the value by which you are increasing the r value. R value is a measure of insulation s ability to resist heat traveling through it. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.

Insulation level are specified by r value. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. The percentage increase increase increase original number 100. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation.

The higher the r value the better the thermal performance of the insulation. To convert rsi to r value multiply the rsi by 5 67826. Thickness inches r value in i p imperial rsi r value in metric 0 5. Conditioned per atsm c1289 test method astm c5181 2.

As a benchmark one inch of solid wood has an r value of 1. For a very good introductory overview article on r value see r values over at the website of. I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. R value of various materials.

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. See the department of energy s doe ranges for recommended levels of insulation below. 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. R3 r18 r21 total roof r value.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. R value is used in the united states. 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.

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 table below shows what levels of insulation are cost effective for different climates and.