Wednesday, August 22, 2012

Aug 22 and 23: R-Value



Home Insulation


Insulation in Iowa   (take a look at this website)

Table of Common R-values

To calculate R-values, we make a sandwich of insulation material.  Just because something is thicker doesn't necessarily mean it is better.  Sometimes, though, higher R-value material is more expensive.  It's a trade-off, just like many things in life.

Make the following sandwiches for your table on a piece of paper, big enough for the entire class to see.:

A sandwich with a R-value of 15 or better
A sandwich with a R-value of 50 or better
A sandwich with a maximum thickness of 6 inches
A sandwich with a maximum thickness of 12 inches

Also, when it comes to windows, we have a problem...It is going to be a very thin sandwich, unless we put up drapes (curtains) or some sort of a quilted batting at night.  Even so, that part of the wall will be colder.   The other trade-off is that windows that have bigger R-values have a bigger cost.

Based on this, what type of windows do you think your house should have?




Personal Evaluation (to be filled out in teams of two)

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