Attic Ductwork R Value

The effective r value of a buried duct installation depends on the size of the ducts the r value of the duct insulation and the depth of the loose fill insulation.

Attic ductwork r value.

When determining how much insulation you need don t guesstimate calculate. Was your ductboard existing and you added a zoning system. Know exactly how much you need with our project calculators. 7 948 btu hour 0 66 ton the numbers are even higher for the additional heating load.

Return ducts ductwork that brings expended air back to the hvac system to be filtered reconditioned and redistributed require insulation with an r value of 3 5 for exterior ducts and ducts in a ventilated attic or unvented attic above an insulated ceiling. He d add open cell foam below the roof deck to give the assembly the required r value but the bids range from 40 000 to 60 000. If the insulation is a foam board or sprayed on foam use any visible label information or multiply the thickness in inches by 5 to estimate the r value. I m looking at you mississippi and alabama r 6 and r 4 2 are common r values for ducts.

The mass of the insulation consisting of both its density and thickness and the compression ratio at installation which determines the final compressed density and effectiveness of the insulation. If it was you don t have much recourse. Add insulation to attic. Not sure where you are at but here in florida the minimum r value for ducts installed in an attic or any unconditioned space is r 6.

Table 1 shows effective r values for 8 inch round ducts at three attic insulation levels and three duct insulation levels r 4 2 r 6 and r 8. The duct insulation r values i mentioned above are what s on the product label. The higher the r value the greater the insulation performance. Ducting values are determined by two factors.

R values represent the heat resistant properties of an insulating material. Existing 3 4 inches of insulation. Some other factors to consider. 6 305 btu hour 0 53 ton r 4 2 duct insulation.

It will most likely be a fiberglass batt so multiply the thickness in inches by 3 2 to find out the r value or the r value might be visible on a product label. Or you live in a state that doesn t require r 8 on ducts in attics. Recommended insulation levels for retrofitting existing wood framed buildings. How often do you think you get the full labeled r value.

There are no r value requirements for ductwork installed in other locations. It comes down to three options the first of which is to convert his attic into a conditioned space by installing 4 1 2 inches of polyiso insulation above the roof deck and then adding a new standing seam metal roof. R value measures how well certain building insulation materials can resist heat. R 6 duct insulation 6 305 btu hour 0 53 ton r 4 2 duct insulation 7 948 btu hour 0 66 ton.