Where to add insulation

[Tom_in_SC]

Where would the money be better spent - going from R19 to R21 with high-density batts in outside walls (they are 2x6)
OR
going from R30 to R38 (or more) overhead?

Any idea (ballpark) what the upgrade cost for either of these should be?

Thanks!
Merry Christmas!!

[Rich]

I would say R38 minimum in the ceiling. And if you have any money left - put it into the doors and windows.

[David]

Tom -

It's hard to give an absolute answer. Do you have a one story home or two? What is your perimeter length and what is your sf?

There's no magical formula, but maybe we can gain some insight.

Increasing the ceiling from 30 to 38 in South Carolina isn't gonna do much for you, IMHO. Going from 19 to 21 won't help a huge amount, either.

My advice to you is to learn about airtight drywall approach and implement it as best you can.

Or, putting on some radiant barrier (techshield) roof decking or paying for rightsized hvac equipment.

Lots of options to choose for your money. Think more than insulation. Just my $.02. Carry on....

[Sweep]

Definitely put it in the roof.

[Tom_in_SC]

David,

One story over a full basement
About 3500 sf.
I will check into the airtight drywall approach.
Too late for techshield. Roof is already on.
I got the HVAC sized right (Hi Richard)
Thank you!

[rabadger]

Put it in the ceiling.

[David]

On a one-story it is typically better to have it in the ceiling. On a two story, I think it depends on how open the floor plan is. On a traditional two story, it's better in the walls.

Richard, this question could have been answered by your hvac software, right? That is, assuming you knew all the other information about the house and climate.

[MCC]

Many New Codes Require R- 38 In The Ceiling. As Far As Your Answer I Would Say The Ceiling But Would Need More Details. Wall Construction , Exterior Composition Roof Type, Etc.

[Tom_in_SC]

Richard's HVAC software has already worked on it, based on R21 and R38. Seems that the local insulation contractors are really used to doing R19 and R30. So, I wondered which one to argue/talk with them about first. Ceiling it is. Thanks!