We are building a 3650 square foot home in Land O Lakes Florida. We have upgraded our windows to two pane low e, have insulated our garage door, and are having foam injected into our cinder blocks.

The home is basically one story with a 750 square foot bonus room upstairs.

THe builder quoted us 3600 to install a radiant barrier. We thought the quote was overpriced and pushed back on the builder - still waiting for a response on that one.

The question here is DO we really need a radiant barrier. We are having R30 insulation blow into the attic and all the walls are R-19 which is as high as you can go?

Will we really recoup the savings here even if I can get the builder to come down on his price for the radiant barrier. I have also read that radiant barriers have not been tested past 10 years; so if you can't recoup your savings in the first 10 years you will never recoup them.

HELP - need some info on this one.

On a sunny summer day, solar energy is absorbed by the roof, heating the roof sheathing and causing the underside of the sheathing and the roof framing to radiate heat downward toward the attic floor. When a radiant barrier is placed on the attic floor, much of the heat radiated from the hot roof is reflected back toward the roof. This makes the top surface of the insulation cooler than it would have been without a radiant barrier and thus reduces the amount of heat that moves through the insulation into the rooms below the ceiling. Excerpt from Radiant Barrier Attic Fact Sheet.

Sounds like you could purchase the amount of Barrier to cover your Ceiling Joist and wrap your second floor walls and install it yourself. That is if the bonus room has no roof cuts nailed to the walls. Installation is a matter of placing a blanket over a bed for the joists. Keep in mind this is just one method of placing the barrier