Attic Ductwork R Value

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.

Attic ductwork r value.

It was new when the ac was put in 7 years ago. Recommended home insulation r values. R value is a measure of insulation s ability to resist heat traveling through it. The higher the r value the better the thermal performance of the insulation.

I check on the oc website and find that the 4 3 is the lowest r value they make. Recently i had another hvac company come out and put in a new bathroom vent and they told me they believed the duct work was full of water. The attic ductwork is flex duct work. Insulation level are specified by r value.

My attic gets hot and so i was wondering how much cool air i was losing to the heat of the attic. The higher the r value the better the thermal performance of the insulation. R value is a measure of insulation s ability to resist heat flow. This is why the r values are so different.

Allison bailes of decatur georgia is a speaker writer building science consultant and the author of the energy vanguard blog. I called out the original hvac company and they took a look and said they saw no water. 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. And that means it s time to deal with duct insulation in a more meaningful way than just increasing the required r value to 8 for ducts in attics.

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. So i notice the ductboard is oc s quietr with an r value of 4 3. Since the installation is in an unconditioned attic space i went up and looked at the duct install. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

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. Insulation levels are specified by r value. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. Add the right kind of insulation.