The duct system is no longer in a space that gets to 140° in the summer; especially when you’re pushing 58° degree conditioned air thru the ducts to bring the home’s conditioned spaces to a comfortable temperature (hint: Like 75°).
Yes, there are benefits: better energy efficiency, better comfort plus less wear & tear on the HVAC equipment, because the ducts are in a conditioned space.
However, there can be some drawbacks: You need the remove the insulation that is in the attic on the attic floor or you could have some troubles.
● Moisture issues
● Air Leakage issues
● Odors &IAQ problems
1) The attic floor covered with insulation can cause a temperature differential in the attic leading to moisture or sweating issues once you seal the roof deck with foam.
2) When they apply the foam, they need to get to all the places where there might be air leaks, like the eves or roof/wall connection; that insulation gets in the way of a complete seal job for the foam. Raking it back can sometimes be ok but this has to be correct or some foam will be missed & the attic won’t be totally sealed.
3) That old insulation is full of dust, debris, and contaminates; not to mention that mouse that had a nest up there, rat poop, bat guano, the remains of a dead squirrel, remnants of rat poison that someone put up there ten years ago to kill that squirrel, &some teenager’s forgotten drug stash. Those are just a few of the things I’ve found in attics.That newly sealed attic allows all those things to migrate into the house, now that the attic is no longerventilated, think about it.
Will you have problems if you don’t remove the old insulation? Maybe.Maybe not. I know of homes where they left the old insulation in place and everything seems to be OK. Usually that happens in homes that are still pretty leaky even after sealing the attic However, If you want the old insulation out that can be accomplished fairly easily , that is a service we can provide for your home’s comfort & health.
Many people ask us for help with concerns they have regarding better IAQ & this is just one important piece of information we want you to know. We want to share ideas so you can have a heathier indoor Environment.