Skip to main content
5 events
when toggle format what by license comment
Mar 13, 2019 at 23:09 comment added Bungle Good point - although I'd be surprised if the thickness of wood they use counts for that much. Wood's R-value is only roughly R-1 per inch.
Mar 13, 2019 at 23:05 comment added Nate S. It appears that this company makes wood-faced doors as well, so I'm guessing the 0-R-value steel ones are probably not what they used for this calculation. Probably you'd have to ask them what part of the value is attributable to their foam, and what part is the (unspecified) cover material.
Mar 13, 2019 at 23:01 vote accept Bungle
Mar 13, 2019 at 23:01 comment added Bungle Thanks, Nate! Somehow I missed that data sheet. I'm still skeptical, though, as the first equation on page 3 shows that the air films total R-0.85 and the steel surfaces total R-0, meaning they're still attributing R-19.55 to the foam interior. That's either ~R-9.8 per inch, or the R-20.4 door is more than 2" thick. This is probably the best we can figure it out, though. It's also good to confirm that their R-values are not measured installed values (I had assumed they weren't), but theoretical calculations that certainly won't match real-world conditions. Thanks again.
Mar 13, 2019 at 21:57 history answered Nate S. CC BY-SA 4.0