Roof Insulation R Value Chart

Recommended home insulation r values.

Roof insulation r value chart.

Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. Insulation level are specified by r value. Conditioned per atsm c1289 test method astm c5181 2.

The table below shows what levels of insulation are cost effective for different climates and. The percentage increase increase increase original number 100. 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. R3 r18 r21 total roof r value.

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. R value is used in the united states. 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. R value chart for enerfoil tm rigid foam faced insulation.

I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. R value is a measure of insulation s ability to resist heat traveling through it. R value of various materials. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

The higher the r value the better the thermal performance of the insulation. 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. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1. See the department of energy s doe ranges for recommended levels of insulation below.

Rsi r value système international is the metric equivalent. You should of course see the manufacturer provided technical data sheet for the r value of specific products. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. 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.

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.