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

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

--- i'm skeptical...

 

 

Views: 191

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

Lynda Wright is now a member of Home Energy Pros
10 minutes ago
Sean Lintow Sr replied to Bud Poll's discussion Basing air exchange on house volume??
"Sorry Bud but I think you need to clarify your issues with using volumes to calculate ACH As for…"
11 hours ago
Profile IconWes Anderson, Jean-Paul and Bryan joined Home Energy Pros
Friday
Dennis Heidner commented on Dale Stephens's blog post LED Lighting 24-month update 18,240 hours & counting
"Dale, good write up. For the landscaping bulbs,  if they had been T3 12V wedge bulbs,  I…"
Friday
Brett Little commented on Tom White's video
Thumbnail

The Future of Housing - And How Airtightness Can Help

"It's very true! So many people and contractors have tons of insulated attics but no air seal…"
Thursday
Chris Leach replied to Richard Beyer's discussion "The Dangers of Using Spray Foam Insulation"
"The problems will surface soon enough . Why don't we take a second look at this over rated…"
Thursday
Don Fitchett commented on Tom White's video
Thursday
tedkidd replied to Bob Blanchette's discussion How does Cycles Per Hour affect real world AFUE?
"Want to spot a simpleton? It's a guy who thinks EE and comfort are disconnected.  Want…"
Thursday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service