Suggested R Value For Attic

R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.

Suggested r value for attic.

R value measures how well certain building insulation materials can resist heat. Where you live different climates require different insulation r values. As a benchmark one inch of solid wood has an r value of 1. See the department of energy s doe ranges for recommended levels of insulation below.

Installing more insulation in your home increases the r value and the resistance to heat flow. But newer homes in central and southern arizona are insulated to ratings of r 30 to r 38 while newer homes in northern arizona generally have attic insulation at r 60 because of colder winters. The r value of the insulation for every inch of thickness depends on the type of insulation. The recommended r value for attic insulation in ontario is between r 50 and r 60.

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. 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. When determining how much insulation you need don t guesstimate calculate.

Existing 3 4 inches of insulation. Blown in cellulose insulation can carry an r value of 3 2 3 8 per inch of thickness. Recommended insulation levels for retrofitting existing wood framed buildings. The recommended r value for attic insulation in our area of the country minnesota is 49.

When calculating the r value of a multilayered installation add the r values of the individual layers. To give you a quick example if you blow in 18 of insulation into your attic with an r value of 3 0 per inch you ve got an effective r value of 3 x 18 54. The r value of some insulations also depends on temperature aging and moisture accumulation. While some ceilings in the southwestern part of the united states require a minimum of r 19 insulation most attics or ceiling areas require a minimum of r 38 in the ceiling.

The higher the r value the greater the insulation performance. The amount of insulation recommended for your home will vary depending on a number of factors. You will need a higher r value of insulation if you live in the northeast than if you live in southern california.