Also, I would recommend that the ASHRAE handbook years are sequential so that the newest book's index will list the correct pages for the other three books. I got by just fine with 2009-2012.
I agree with all of this. I would also add that the Trane Air Conditioning Manual is a great resource that explains psychrometrics very clearly with 30-40 examples per chapter. It's an older blue colored book but can be found on Amazon and Ebay.
I noticed this same problem you are showing with the air space R-values. The only way I could rationalize their number is that they mention it's 90 deg outside, and 90 deg average for the air space. Would this mean that sometimes the interior space is above 90 deg, therefore there would...
Well I ended up loading the chart protractor into cad and finding all of the angles. Attached is a image of the protractor with angles, if anyone is interested.
Does anybody know if there is such a thing as a psychometric protractor? I'm wanting a clear plastic protractor with the SHR listed on it instead of degrees. I finding that I lose a lot of accuracy trying to transpose the SHR printed on the charts.