R value is thermal resistance in imperial/USC units. The equivalent in SI
is RSI, which is what is used in Canada. From Wikipedia:
Around most of the world, R-values are given in SI units, typically
square-metre kelvins per watt or m²·K/W (or equivalently to m²·°C/W). In the
United States customary units, R-values are given in units of ft²·°F·h/Btu.
It is particularly easy to confuse SI and US R-values, because R-values both
in the US and elsewhere are often cited without their units, e.g. R-3.5.
Usually, however, the correct units can be inferred from the context and
from the magnitudes of the values. United States R-values are approximately
six times SI R-values [2].
John F-L
----- Original Message -----
From: <mech...@illinois.edu>
To: "U.S. Metric Association" <usma@colostate.edu>
Sent: Tuesday, January 11, 2011 3:42 AM
Subject: [USMA:49473] Re: Btu
R Value if *defined* by IP units, not by SI units, except second.
---- Original message ----
Date: Tue, 11 Jan 2011 08:56:47 +1100
From: Pat Naughtin <pat.naugh...@metricationmatters.com>
Subject: [USMA:49467] Re: Btu
To: "U.S. Metric Association" <usma@colostate.edu>
Dear Robert,
...
After that I am in doubt. Is the "R value" really
a metric value?
...
