R Rating For Wall Insulation

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.

R rating for wall insulation.

Recommended home insulation r values. 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. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system.

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. The r value per inch for different types of insulation varies depending on the. The table below shows what levels of insulation are cost effective for different climates and. 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.

Typically a higher insulation r rating means better climate control and better energy efficiency for your home. See the department of energy s doe ranges for recommended levels of insulation below. 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. 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 value is a measure of insulation s ability to resist heat traveling through it. For every type and material of insulation check the r value per inch of thickness that the manufacturer has listed. For example insulation that is compressed will not provide its full rated r value. In the context of building and construction the r value is a measure of how well a two dimensional barrier such as a layer of insulation a window or a complete wall or ceiling resists the conductive flow of heat.

A higher insulation r value usually means a higher price point as well. 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. R stands for thermal resistance. Insulation level are specified by r value.

In most wall applications you will use r 13 or r 15 kraft faced fiberglass insulation rolls for these two by four stud walls.