Recommended R Rating For Wall Insulation

Insulation level are specified by r value.

Recommended r rating for wall insulation.

Note from this. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. The table below shows what levels of insulation are cost effective for different climates and. R value is a measure of insulation s ability to resist heat traveling through it.

An r value is a rating which measures how well insulation can resist heat flow. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. The overall r value of a wall or ceiling will be somewhat different from the r value of the insulation itself because heat flows more readily through studs joists and other building materials in a phenomenon known as thermal bridging. How to achieve r 21 in a 2x4 wall.

Fiberglass is usually installed between studs joists and rafters in unfinished walls floors and ceilings. However it offers relatively low r values spanning r 3 1 to r 4 3 per inch. The r value per inch for different types of insulation varies depending on the. See the department of energy s doe ranges for recommended levels of insulation below.

The r value is a calculation which measures the flow of heat through an insulation product or its. In most wall applications you will use r 13 or r 15 kraft faced fiberglass insulation rolls for these two by four stud walls. R value level depends on a number of things such as the type of material its density and thickness. Recommended home insulation r values.

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. A 12 inch thick fiberglass blanket rated at r 4 is enough to reach the recommended insulation level of r 48 for attics located in zone 4. Insulation is rated in two ways r value and u value. For example insulation that is compressed will not provide its full rated r value.

While rated differently these two types of insulation are close enough in thickness that they can both fit into modern two by four wall systems. While there are additional considerations such as venting and moisture problems to take into account when you insulate under floors the united states department of energy recommends an r 25 rating in cold climates and an r 11 in warmer parts of the country. R stands for thermal resistance.