Connie, attic insulation does not have a time frame for replacement. Condition is the determining factor. Blown in insulation that has been contaminated by moisture, critter droppings or smoke should be replaced. Blown in insulation that has compacted may be replaced but may also be effectively augmented with the addition of new blown in or roll fiberglass insulation. The insulation packaging will disclose the "R" value of the insulation per inch of depth. Due to rising energy costs the
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proposed "R" value has been steadily pushed upward. A total "R" value of 40 is not unreasonable. Remember, also, that floored areas restrict the effectivenes of insulation. Stuffing additional insulation under flooring won't add to your savings. Compressing the insulation reduces dead-air spaces and its the dead air that really cuts down on heat transfer. Don't forget to deal with heat transfer around and through the attic access. Whether its a door or pulldown ladder that access is a gaping hole in the insulation. Sealing around the or and adding an insulated trap door over the pull down closes the system.
Great tips, BARMS. Connie, as far as how much insulation, that depends where you are located. Here's a map that shows you the recommended insulation levels for different regions.
We have had success with a spray applied radiant barrier applied to the underside of the roof deck instead of augmenting the existing insulation. Works really great in Florida hot regions. Helps reduce attic temperature 40-50 degrees in summer
The installation of any kind of radiant barrier must be weighed against the cost savings of simply air sealing the attic and installing the proper amount of insulation for the region. Add proper ventilation and your done.
Radiant barriers offer no useful R value, they raise the temps of the roof shingles about 5-10 degrees or more, although do not void warranties, They only work when their shiny and reflective.
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Also if radiant barriers were such a great thing, They would have been part of the building codes already.
While there are lots of products on the market to help save money on heat and cooling bills, nothing to date has stood the time like sealing, insulation and proper ventilation.
http://www.energystar.gov/index.cfm?c=home_s...
Radiant barriers offer no useful R value, they raise the temps of the roof shingles about 5-10 degrees or more, although do not void warranties, They only work when their shiny and reflective. ...»
While there are lots of products on the market to help save money on heat and cooling bills, nothing to date has stood the time like sealing, insulation and proper ventilation.