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larryrose11 · 07-17-2008, 04:34 PM

Daox,
FIRST seal up your attic area: Put expanding foam along the top of wall headers, wire protrusions and such. The existing fiberglass can be your guide: It will be dirty wherever the is an air leak. I can not emphasize the sealing enough.
On attic insulation.
I would use cellulose over the top, not fiberglass. Testing shows that it just dosnt perform as rates in the cold! It looses 20% of its r value.
The fact sheet I have seen recommending R-49 from the enegystar website: Recommended Levels of Insulation : ENERGY STAR
is dated from 1997, and is based on Natural gas prices from then.
I would shoot for R-60
On Eaves: Do you hav an energy heel truss? If not, (like my house) then you should put the good stuff along the eves, the r6.5 / inch board. Reason is, that area is thin, and with celulose, you will be only able to get 3.5 inches or R3.5/inch = 12.25 at the eves.
I did this, and a boat load of sealing, and my heating (Nat gas) bill drop dramatically. They are now $50 in the winter here in Det, MI.

07-17-2008, 04:34 PM	#4 (permalink)
larryrose11 Mad Scientist Join Date: Jul 2008 Location: Detroit area, MI. Posts: 42 Silver Civic - '97 Honda Civic 2 door DX coupe 90 day: 35.57 mpg (US) Wagon - '01 Ford Foccs ZTX 90 day: 35.46 mpg (US) Thanks: 0 Thanked 2 Times in 1 Post	Daox, FIRST seal up your attic area: Put expanding foam along the top of wall headers, wire protrusions and such. The existing fiberglass can be your guide: It will be dirty wherever the is an air leak. I can not emphasize the sealing enough. On attic insulation. I would use cellulose over the top, not fiberglass. Testing shows that it just dosnt perform as rates in the cold! It looses 20% of its r value. The fact sheet I have seen recommending R-49 from the enegystar website: Recommended Levels of Insulation : ENERGY STAR is dated from 1997, and is based on Natural gas prices from then. I would shoot for R-60 On Eaves: Do you hav an energy heel truss? If not, (like my house) then you should put the good stuff along the eves, the r6.5 / inch board. Reason is, that area is thin, and with celulose, you will be only able to get 3.5 inches or R3.5/inch = 12.25 at the eves. I did this, and a boat load of sealing, and my heating (Nat gas) bill drop dramatically. They are now $50 in the winter here in Det, MI.