I sat through a free dinner (chicken or shrimp) and heard a guy try to
sell me roll-out multi-layer aluminum foil insulation (apparently with
mylar in the sandwich). It is perforated so as to allow moisture
through, and installed over top of the fiberglass/cellulose/whatever
in the attic. It is claimed to reduce heat gain in the summer and
heat loss in the winter.

I don't doubt that it would be effective to some degree, but I gather
that the optimal placement for heat-gain reflective insulation is on
the underside of roof rafters, and I think that the optimal placement
for heat loss would be on the warm side of the house in the winter,
i.e. just behind the drywall, with an air gap. Laying the stuff over
12 inches of fiberglass is optimal for neither situation, but it still
might be ok.

Does anybody know what increase in effective r-value you might get
this way? I live in the north and don't use AC, so reducing heat
loss is generally more important a consideration. I searched for a
while with google but didn't find anything very relevant.

I have truss rafters, incidentally, and installing this would be a
total pain in the ass.

On Apr 1, 7:31�am, wrote:
I sat through a free dinner (chicken or shrimp) and heard a guy try to
sell me roll-out multi-layer aluminum foil insulation (apparently with
mylar in the sandwich). �It is perforated so as to allow moisture
through, and installed over top of the fiberglass/cellulose/whatever
in the attic. �It is claimed to reduce heat gain in the summer and
heat loss in the winter.

I don't doubt that it would be effective to some degree, but I gather
that the optimal placement for heat-gain reflective insulation �is on
the underside of roof rafters, and I think that the optimal placement
for heat loss would be on the warm side of the house in the winter,
i.e. just behind the drywall, with an air gap. �Laying the stuff over
12 inches of fiberglass is optimal for neither situation, but it still
might be ok.

Does anybody know what increase in effective r-value you might get
this way? �I live in the north and don't use AC, so �reducing heat
loss is generally more important a consideration. �I searched for a
while with google but didn't find anything very relevant.

I have truss rafters, incidentally, and installing this would be a
total pain in the ass.

with trusses just add more regular blown in insulation.

On Apr 1, 7:31*am, wrote:
I sat through a free dinner (chicken or shrimp) and heard a guy try to
sell me roll-out multi-layer aluminum foil insulation (apparently with
mylar in the sandwich). *It is perforated so as to allow moisture
through, and installed over top of the fiberglass/cellulose/whatever
in the attic. *It is claimed to reduce heat gain in the summer and
heat loss in the winter.

I don't doubt that it would be effective to some degree, but I gather
that the optimal placement for heat-gain reflective insulation *is on
the underside of roof rafters, and I think that the optimal placement
for heat loss would be on the warm side of the house in the winter,
i.e. just behind the drywall, with an air gap. *Laying the stuff over
12 inches of fiberglass is optimal for neither situation, but it still
might be ok.

Does anybody know what increase in effective r-value you might get
this way? *I live in the north and don't use AC, so *reducing heat
loss is generally more important a consideration. *I searched for a
while with google but didn't find anything very relevant.

I have truss rafters, incidentally, and installing this would be a
total pain in the ass.

You dont know if you ate chicken or shrimp!

On Apr 1, 11:23*am, ransley wrote:


You dont know if you ate chicken or shrimp!

Come on Mark, you've been to these kinds of promos before. The food
stays in the warmers so long it all tastes alike. That is, if there's
any taste left at all...
When in doubt, just eat the peas, identified by the green color,
assuming the meat hasn't stayed outside too long.

Joe

wrote:

Does anybody know what increase in effective r-value you might get this way?

Very good, with lots of layers.

I live in the north and don't use AC, so reducing heat loss is generally
more important a consideration. I searched for a while with google
but didn't find anything very relevant.

http://www.rima.net/handbook/HandbookAll0504.pdf

See document pages 23-27...

You might enjoy solar heat with airflow from a low-mass sunspace and
shiny hot ceiling mass over the living space, as in the Barra system.

Nick