R30 in attic

[macavoy]

Just bought a new home here in the desert. Standard insulation is R19 in the walls and R30 in the attic. How much would blowing in extra insulation help in the attic with electric bills???? Ive heard it go both ways. Thanks.

[chrisprickett]

One story or two?

[monte]

If you ducting is in the attic, I would add more insulation over the ducting (Ducting is either a R4 or R8) instead of cooling your attic.

Up here they have a R40 in the attic. Manufacture homes have a R50. Blow-in insulation is cheap return on your investment.

[macavoy]

Its a ranch, ducting in attic. So blown in extra insulation is well worth it??

[Paul MacLean]

R30 is recommended for attics here in Central Texas. Assuming the R30 is uniformly and properly installed, the cost of additional insulation might have a long payback. If it takes 10 years to recover the cost of additional insulation in energy savings, it might not be worth adding more insulation. Just food for thought...

[hausdok]

Hi,

It's impossible to make blanket recommendations when it comes to recommended R-values needed. You have to look at the climate, the type of construction and the materials used and a host of other factors such as the percentage of glass in the exterior walls, skylights etc..

Oak Ridge National Laboratory's Building Envelope Program has published an information sheet that will help you understand all of this and directs you to where you can find an interactive Zip code calculator that will help you determine what's appropriate for your area.

ONE TEAM - ONE FIGHT!!!

Mike