white metal roof vs traditional silver metal

[joesgot4]

i'm thinking of putting a metal roof on my house and i dont know which color would be more efficient as far as keeping the house cool WHITE or SILVER? thanks troy p.s. i just installed a quadrafire wood stove for heat and man is it awesome!

[cfg83]

joesgot4 -

I vote white with an elastomeric paint/coating.

CarloSW2

[Daox]

There are companies that offer special reflective pigments in their metal roofing paint to further reflect light. I'd check that out.

[Ryland]

I would go with silver as it's going to be cheaper and zinc oxide white, if I remember right has this nifty property where it is able to reflect light and heat and also radiate heat faster then other colors, and over time that silver galvanized metal is going to turn gray from the zinc turning to an oxide.
It's also a classic and if you are going to buy a roof that will last 100 years go with a classic, either way the paint is not designed to last 100 years.

[tasdrouille]

Unless you absolutely need to redo the roof, wouldn't a radiant barrier stapled in the attic be the cheapest solution?

[jmf]

Most of the roof colors have the same efficiency. Check the company you are going to use to see if the roofing is energystar rated, if it is the colors will be the same and there is a tax credit.

[Ryland]

Originally Posted by jmf

Most of the roof colors have the same efficiency. Check the company you are going to use to see if the roofing is energystar rated, if it is the colors will be the same and there is a tax credit.

That is pretty far from true, light colors reflect alot more heat then dark colors, in the summer this keeps the roof and the attic cool, allowing the insulation to stay cooler, in the winter dark colors let the snow melt sooner, snow acts as extra insulation, yes, snow can be insulation as it's better to have your attic just below freezing then it is to have it -20F.

[jmf]

"Englert’s Ultra-Cool metal roof coatings dramatically increase the reflectivity of medium to darker color roofs, meeting Energy Star specifications for cool roofs. Consequently, architects and builders can enhance the appearance of their projects with the use of medium and darker colors and save warm weather energy costs because reflectivity keeps the roof and interior spaces cooler. In addition, the use of Englert’s Ultra-Cool metal roof coatings has several positive impacts on the roof, its structure and the environment. Heat is reflected away from the building, urban smog is reduced when environmental temperatures are reduced, the life expectancy of the roof increases due to less expansion and contraction and public monetary incentives are available for using reflective roofing products. Englert standing seam metal roofs are available in a wide variety of Ultra-Cool colors including dark bronze, charcoal gray and matte black."

My neighbor is a dealer for Englert. This is from thier site.

[cfg83]

jmf -

Originally Posted by jmf

"Englert’s Ultra-Cool metal roof coatings dramatically increase the reflectivity of medium to darker color roofs, meeting Energy Star specifications for cool roofs. Consequently, architects and builders can enhance the appearance of their projects with the use of medium and darker colors and save warm weather energy costs because reflectivity keeps the roof and interior spaces cooler. In addition, the use of Englert’s Ultra-Cool metal roof coatings has several positive impacts on the roof, its structure and the environment. Heat is reflected away from the building, urban smog is reduced when environmental temperatures are reduced, the life expectancy of the roof increases due to less expansion and contraction and public monetary incentives are available for using reflective roofing products. Englert standing seam metal roofs are available in a wide variety of Ultra-Cool colors including dark bronze, charcoal gray and matte black."

My neighbor is a dealer for Englert. This is from thier site.

Yes, but those are also the "normal" colors that meet aesthetic expectations of what people want to buy. I went here :

Englert: Ultra-Cool Coatings are available in the following popular colors


In the above you can see that the white has a better Solar Reflectivity Index ...

Atlanta Roofing | Cool Roofs | Green Roofs | LEED Certified Roofs | Solar Roofing in Atlanta | Green Wave Forever

Cool Roofs - Cool roofs are a very inexpensive way to significantly lower your energy bills. A “Cool” roof is cool because it has a high Solar Reflectivity Index(SRI) and High Thermal Emissivity. These are two terms that you will hear when learning about sustainability and energy efficiency. Solar Reflectivity Index refers to how much sunlight is reflected off the surface. To qualify for a roof to be “cool” and earn the appropriate LEED Credits, a roof must have an SRI of 78 or higher. Thermal Emissivity refers to a materials ability to release stored heat. This factor is a number between 0 and 1. The higher the number, the less heat that a surface holds.

CarloSW2

[bgd73]

Originally Posted by Ryland

That is pretty far from true, light colors reflect alot more heat then dark colors, in the summer this keeps the roof and the attic cool, allowing the insulation to stay cooler, in the winter dark colors let the snow melt sooner, snow acts as extra insulation, yes, snow can be insulation as it's better to have your attic just below freezing then it is to have it -20F.

not necessarily. there is enamels/urethanes that keep dark colors cool, just by a high uv rating...it needs to accept uv to accept heat, and then be able to give it away again.

a roof should get hot, there is organic and gases in the house that need out, and other physics that just needs up, unless you have a common sensed air circulation?

making a dirty old barn out of the house ...ewww.