Science Buddies: "Ask an Expert"

Would painting a house a darker color in a cooler climate help keep the warmer as opposed to painting it a lighter color in the same climate?
Thank you,Ryann

Hi, this is a very complicated question, that has many variables. For example, the amount of sunlight incident on the house will determine the effectiveness of painting it a darker. Also, houses are built with insulation, which keeps the inside temperature as separate from the outside temperature as possible. This means that it would keep the temperature of the outside of the the house from effecting the temperature of the inside very much.
This is a very interesting question, with many real-world implications, so I would do some research on the internet, I bet that there will be many pages on this topic.
Hope this helps with your question, and good luck on your project!

To continue the prior response...

The general answer is Yes, a dark color will be better when it is cold and you want to gain energy from sunlight.

However, the color you see will have a small effect, because of several factors.
1. Insulation, as previously stated.
2. The painted part is only a portion of the house, there are also windows, doors, and the roof.
3. The roof is somewhat isolated from the house by the attic air, especially if it is properly vented.
4. The paint may have different reflective values in the non-visible portion of the spectrum.
5. Need to consider the sunlit and shaded portions, and the effect of the eves and neighboring trees and plants.
6. Air infiltration.
7. Air exchanges that are intentional, such as exhause fans, flues, and open windows and doors.

Bob