3
   

Painting the Roof White

 
 
gollum
 
Reply Tue 24 May, 2011 06:15 pm
Some people recommend painting a building's roof white in order to reduce energy consumption. However, wouldn't that increase the building's heating cost in the winter?
  • Topic Stats
  • Top Replies
  • Link to this Topic
Type: Question • Score: 3 • Views: 1,067 • Replies: 9
No top replies

 
edgarblythe
 
  1  
Reply Tue 24 May, 2011 06:37 pm
@gollum,
Most of the shingles that sell are gray. The reason is this: White repels the heat best in the daytime. But, at night, white releases heat slower than black. Gray is a compromise between the two.
0 Replies
 
DrewDad
 
  1  
Reply Wed 25 May, 2011 12:27 am
@gollum,
They did a study on it, and found that lighter shingles cut overall energy costs.
DrewDad
 
  1  
Reply Wed 25 May, 2011 12:28 am
@DrewDad,
http://www.azcoolroof.com/downloads/Resources/White%20Roofs%20Are%20A%20Cool%20Way%20To%20Cut%20Energy%20Costs.pdf
gollum
 
  1  
Reply Sun 29 May, 2011 01:48 pm
@DrewDad,
DrewDad-
Thank you.

However, the article is silent on higher heating costs in the winter. Perhaps because it was written for a Florida newspaper. I live in New York City.
roger
 
  2  
Reply Sun 29 May, 2011 02:22 pm
@gollum,
No. White reflects light. It also radiates less heat. If the house is hot because of sunlight, white will cool it. If it is hot because of a heating system, the white color will radiate less than a black roof.
tsarstepan
 
  1  
Reply Sun 29 May, 2011 03:02 pm
@gollum,
You're not going to get much direct sunlight in the winter (especially NYC) so it doesn't matter what color the roof is in the season where it's mostly cloudy most of the time.

The only time the color matters is when the sun is out the longest (spring and summer).
0 Replies
 
gollum
 
  1  
Reply Sun 29 May, 2011 03:36 pm
@roger,
roger-
Thank you.

If the house is cold in the winter, would a white roof absorb the least heat and thereby result in an increased fuel bill to heat the house?
roger
 
  2  
Reply Sun 29 May, 2011 05:12 pm
@gollum,
Unlikely. Lets put it like this. The color white will tend to maintain the internal temperature, whether it is hot or cold relative to the outside air. An ultra flat black will tend to make the interior temperature go up or down to match the outside air. Even in the absence of sunlight, those are still the tendencies.
0 Replies
 
DrewDad
 
  1  
Reply Sun 29 May, 2011 05:27 pm
@gollum,
My recollection from the article I heard or read is that it did slightly increase the winter energy costs, but that the summer energy savings were much greater.
0 Replies
 
 

Related Topics

Vertical Gardens - Discussion by dlowan
Is this the worst billboard? Opinions? - Discussion by ossobuco
Our new public library - Discussion by littlek
Illegal Parking In Handicapped Spots - Question by Victor Murphy
Don't Drink The Toilet Water! - Discussion by realjohnboy
Ideally shaped city. - Discussion by chai2
 
  1. Forums
  2. » Painting the Roof White
Copyright © 2021 MadLab, LLC :: Terms of Service :: Privacy Policy :: Page generated in 0.03 seconds on 05/15/2021 at 11:26:55