On Fri, 21 Aug 2009 22:30:28 -0600, Tony Hwang
wrote:

Matt Williamson wrote:
Hi,
Where do you live? Is the stud 2x4 or 2x6? FP place may be lot of heat
than heating the room depending what style.

I'm in the North East. Western NY area. That room is framed with 2x4's. So,
is the R value of the existing insulation 3.2 x the thickness of the
insulation?


Hi,
Around 4 x thickness and if batt is compressed or moist it loses R
value. They don't build houses any more using 2x4 studs. It's 2x6 now.
I live in Southern Alberta. Rigid styrofoam panel has higher R value.
And if your FP is not air tight type I'd convert it for heat gain than
loss. Here we all use NG direct vent FPs now.

Styrofoam SM is R5 per inch - so roughlyR20 to fill cavity.
Roxul is R14 for 3.5" batt and moisture does not degrade it like
fiberglass.