Wall Insulation Values

Or component performance alternative of section c402 1 5 roof solar reflectance and thermal emittance fenestration in building envelope.

Wall insulation values.

The table below shows what levels of insulation are cost effective for different climates and locations in the home. Specific insulation requirements of section c402 2 thermal requirements of either. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Fiberglass batts for standard 2 4 walls are now available in low medium and high density products that range from r 11 to r 15.

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 along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. 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. Recommended insulation levels for retrofitting existing wood framed buildings. R value is a measure of insulation s ability to resist heat traveling through it.

R value based method of section c402 1 3 u c and f factor based method of section c402 1 4. See the department of energy s doe ranges for recommended levels of insulation below. An insulating material s resistance to conductive heat flow is measured or rated in terms of its thermal resistance or r value the higher the r value the greater the insulating effectiveness. The higher the r value the better the thermal performance of the insulation.

The ideal attic insulation r value is different than the ideal wall insulation r. 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. 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. While wall insulation is limited by the width of the studs different materials provide higher or lower r values.

Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior air film again no air movement r 0 68 3 4 of reflective air space no convective air movement r 2 89 1 2 drywall r 0 45 interior wall.