"Don Phillipson" wrote in news:idh4ct$ti7$1
@speranza.aioe.org:

"mike" wrote in message
...

I've got this red brick fireplace taking up half a wall.
Capped the chimney decades ago, but it's still siting
there conducting heat outa' the place thru the bricks.
How would one go about calculating the "R-value"
to estimate the heat loss. Any useful rules of thumb?

Trying to decide whether to put insulation over the bricks
on inside or outside or both.

I found the reference below in my files;

Concrete block (8")
R-Factor
Concrete block (8") 2.0
with foam insulated cores 20
with 4" on uninsulated stud wall 4.3

I very much doubt the middle value, R of 20 for just some foam in the cores
seems way too high. The first and last value seem in the ballpark.

I have a second reference that shows brick ranging from 0.10 to 0.35 per
inch thickness.