2007-11-03 01:18:44 · 7 answers · asked by KENT D 1 in Home & Garden ➔ Do It Yourself (DIY)
Hi Kent,
No, it's not quite that simple. I wish it was - it would make insulation a lot easier to calculate. It is totally dependent on the type of insulation. For instance blown pink fiberglass has an R value of 2.2 per inch while skin faced polyurethane has an R value of 7.1 per inch. Hope that answers your question.
2007-11-03 01:41:59 · answer #1 · answered by Steve in NC 7 · 3⤊ 0⤋
YES,,,to directly answer your Q.
Thumb being an archic unit of measurement.
Certainly it depends on TYPE, but Fiberglass is rated that way; as is constrcution grade TIGHT cellular foam sheet.
BTW; there is no such thing; as TOO much.
Standards in the trades vary to a degree; but obviously wall insulation is usually less in R value than Attic/Crawl space. The problem/ issue is obvious as well. The thickness of the interior of a wall might only be 3 5/8 inches. COMPACTING insulation lowers its R value; especially in Fiberglass.
Steven Wolf
It also depends in part about where you are located. I'm in South Central FL; so R 30 in an attic is sufficient. If I lived in Minnesota; I might want R 45 or more.
2007-11-03 08:06:01 · answer #2 · answered by DIY Doc 7 · 0⤊ 0⤋
I think I remember from high school physics or maybe thermodynamics that the origin of R-value was in inches of concrete...i.e., R13 would be equivalent to the insulation quality of 13 inches of concrete. But I did a quick search on-line and couldn't confirm that, probably because the thermal conductivity of concrete varies, and it isn't what people are interested in using for insulation, either!
Anyway, check out this link:
http://en.wikipedia.org/wiki/R-value_%28insulation%29
It's very informative, and maybe more information than you really want/need about the R-value of some common materials and how to calculate heat loss.
2007-11-03 04:45:44 · answer #3 · answered by Kevin M 2 · 0⤊ 0⤋
its differnt for every type of insulation.fiberglas is most common 3 1/2" of insulation is an r13, 5 1/2" is an R20
2007-11-03 01:28:04 · answer #4 · answered by Tio 6 · 0⤊ 0⤋
R13= 2 1/2" here.
2007-11-03 10:35:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋
No. The density and number of air pckets determine the R value.
2007-11-03 04:01:17 · answer #6 · answered by Kurtis G 4 · 0⤊ 0⤋
depends on the type......
http://www.rvalue.net/
2007-11-03 01:33:54 · answer #7 · answered by mdlbldrmatt135 4 · 0⤊ 0⤋