... with windows with a better R-value than walls ?

http://www.good.is/post/thermogram-shows-the-extreme-efficiency-of-...

--- i'm skeptical...

 

 

Views: 187

Replies to This Discussion

You should be skeptical, Davide!! Something is clearly not right. Windows are about 20% reflective but all of them at that angle could be reflecting the same cold sky.

 

I think the interior temperatures of the buildings were different. I have R=10 windows and even they are warmer than my R=45 walls!


As the image below shows, we can make windows appear pretty much an...
 Interior temps in this image were all the same; the difference is what is being reflected, cold sky (top), warm surroundings (bottom) or a mixed background (middle).

Here is another image showing R=10 windows (Serious brand) on the right and conventional double-glazed, nitrogen-filled windows on the left (there is a screen on the right window of these). Interior temperatures are identical in both rooms.

John

Is the emissivity difference between the glass and the wall making a difference too?

Ed Minch

It is certainly possible as I no longer have the exact specs for the older windows. My belief, however, is that exterior surfaces of both old and new glazings are uncoated so what we are seeing is related only to the difference in actual heat transfer.

For the other image (3 windows stacked), all three windows are identical. The difference in "apparent temperature" is entirely due to differences in the reflected background temperatures.

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Chad Mcaulife posted photos
1 hour ago
Bob Blanchette commented on Jeremy Begley's blog post The Home Envelope : Does it Really Matter in a Heat Loss Calculation
"Infiltration makes a HUGE difference. Look at the heat loads on a windy day vs. a calm one. On a…"
1 hour ago
Bob Blanchette commented on Everblue's blog post Poor HVAC Installation Leads to Increased Energy Use
"That explains a LOT of why HVAC system continue to be sized by the same "rule of thumb"…"
2 hours ago
Profile IconChristian Asdal and Shashank Kirloskar joined Home Energy Pros
2 hours ago
Don Fitchett shared their video on Digg
3 hours ago
Don Fitchett shared their video on StumbleUpon
3 hours ago
Don Fitchett shared their video on Twitter
3 hours ago
Mark posted events
4 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service