Comments for Racine Home Insulators, LLC http://www.racinehomeinsulators.com Insulation, Siding, and Windows Mon, 21 Nov 2011 13:24:57 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comment on Insulation Materials: Cellulose vs Fiberglass by Matt Kranich http://www.racinehomeinsulators.com/2011/insulation-cellulose-vs-fiberglass#comment-3 Matt Kranich Mon, 21 Nov 2011 13:24:57 +0000 http://www.racinehomeinsulators.com/rhi6611/?p=77#comment-3 Great question! The reason has to do with the microscopic structures of fiberglass and cellulose. Fiberglass is literally fibers of glass. These fibers are solid strands that can trap no air inside. So as the attic gets really cold in the winter and we keep in mind that hot air rises, we find very large convection currents (loops) in the fiberglass insulation as the warm air just above the attic floor (at the bottom of the insulation) is able to easily rise up. As it rises it gets replaced by cooler air that is sinking. This is the convection loop and means there is air flow through the fiberglass. With cellulose, because it is a plant based material that contains the dead cell structures of tree wood the properties are much different. We probably all remember that plant cells have cell walls, unlike animal cells that only have a cell membrane. These cell walls stay mostly intact after the tree dies. This is part of the reason wood stays rigid. Even after the processing of recycled paper into cellulose there are still millions of air pockets "within" the cellulose particles due to the cell wall structure. These pockets of trapped air cannot rise up and be exchanged with cold air entering the top of the attic. As a result, the R-value of cellulose is more closely retained. This is further supported by the fact that cellulose does not lose its R-value when it is compressed, where the R-value of fiberglass is almost completely lost when compressed. Because fiberglass has no air pockets within the strands, compression turns it into glass. We all now how bad of an insulator glass is because when we touch our windows in the winter they always feel very cold. Great question! The reason has to do with the microscopic structures of fiberglass and cellulose. Fiberglass is literally fibers of glass. These fibers are solid strands that can trap no air inside. So as the attic gets really cold in the winter and we keep in mind that hot air rises, we find very large convection currents (loops) in the fiberglass insulation as the warm air just above the attic floor (at the bottom of the insulation) is able to easily rise up. As it rises it gets replaced by cooler air that is sinking. This is the convection loop and means there is air flow through the fiberglass.

With cellulose, because it is a plant based material that contains the dead cell structures of tree wood the properties are much different. We probably all remember that plant cells have cell walls, unlike animal cells that only have a cell membrane. These cell walls stay mostly intact after the tree dies. This is part of the reason wood stays rigid.

Even after the processing of recycled paper into cellulose there are still millions of air pockets “within” the cellulose particles due to the cell wall structure. These pockets of trapped air cannot rise up and be exchanged with cold air entering the top of the attic. As a result, the R-value of cellulose is more closely retained. This is further supported by the fact that cellulose does not lose its R-value when it is compressed, where the R-value of fiberglass is almost completely lost when compressed. Because fiberglass has no air pockets within the strands, compression turns it into glass. We all now how bad of an insulator glass is because when we touch our windows in the winter they always feel very cold.

]]> Comment on Insulation Materials: Cellulose vs Fiberglass by Big Daddy http://www.racinehomeinsulators.com/2011/insulation-cellulose-vs-fiberglass#comment-2 Big Daddy Mon, 21 Nov 2011 02:49:56 +0000 http://www.racinehomeinsulators.com/rhi6611/?p=77#comment-2 Why does fiberglass lose it's r-value? and not cellulose. Why does fiberglass lose it’s r-value? and not cellulose.

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