Jason wrote:
Is there such a thing as too much attic insulation? I have R38 in the attic
at the moment, but the local building inspector says they like to see at
least R50 in new homes. Would adding another layer of R38 (total R value
would then be R76) perpendicular to the existing layer of fiberglass be
overkill? Or will it make a difference? Does attic insulation really cut
down on heat gain in the summer and heat loss in the winter? Or is there
some other place to look to cut down on heat gain?

Thanks,


Doing a heatloss calc is not that difficult. I would say that r76 is
overkill, but what if oil hits 5 bucks a gallon?

in general, with good windows, you still lose half your heat out the
windows, more or less. Around half the remaining goes out the roof[both
because of square footage and heat rising]

Look up heat loss calcs on the web, it is an interesting exercise if
nothing else.


You can estimate pretty damn close

My blind screaming 2 minute guess on a 20x40 little ranch with
walls/window/ceiling of r19/3/38 loses over 16 percent of its heat
through the roof, not counting differences in heat movement, so that
means the most you could gain would be $111/1000 spent heating, and
probably more like half that. But if oil went from 2.50 to 7.50 a
gallon......