R Value Of Fiberglass Roof Insulation

The higher the r value the greater the insulation performance.

R value of fiberglass roof insulation.

Click the button to calculate the approximate r value for this job. 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. Rsi r value système international is the metric equivalent.

Know exactly how much you need with our project calculators. This calculator is to be used as an estimating tool only. 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. When determining how much insulation you need don t guesstimate calculate.

To convert rsi to r value multiply the rsi by 5 67826. R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another. See the department of energy s doe ranges for recommended levels of insulation below. Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency.

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. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. Our r value guide to rigid insulation includes the doe s recommended insulation by zone chart r value calculator and base building material r values chart.

R3 r18 r21 total roof r value. 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. 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. The table below shows what levels of insulation are cost effective for different climates and. As a benchmark one inch of solid wood has an r value of 1. 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.

A rigid roof insulation board with high thermal efficiency johns manville r panel is compatible with multiple types of membrane systems. The common denominator among varieties of insulation is the r value. R value measures how well certain building insulation materials can resist heat. The higher the r value the better the thermal performance of the insulation.

Insulation level are specified by r value. Open cell polyurethane spray foam 3 5 inches. R panel is manufactured with a closed cell polyisocyanurate foam core bonded to fiberglass reinforced facers and designed for use over metal nailable and non nailable roof decks with a variety of membrane systems. Loose fill such as fiberglass cellulose mineral wool 8 23 inches thick 30 50.

The percentage increase increase increase original number 100. R value of various materials. What r value do i need.