In Austin, like the rest of the U.S., the majority of homes have an asphalt roof. One of the reasons asphalt shingles are the most common residential roofing material, beyond affordability, is the vast color selection. With asphalt roof shingles colors are virtually limitless because the granules on top are covered with a ceramic coating that can give them color.
When we look at installation data for roofing shingles it's clear that some colors are much more common than others. In Texas brown, grey and charcoal are very popular options for roofing materials. In Austin, charcoal grey is a favorite for its sleek, modern appearance.
Aesthetics are the primary reason homeowners tend to choose a brown, grey or black roofing material. They are neutral colors that compliment just about any color of exterior paint, which is much easier to update than a roof. Another benefit is that darker colors also hide discoloration, dirt and debris better.
However, the tendency to go with darker colors is changing for one very practical reason. Dark roof colors are less energy efficient.
The reason color matters so much is because of the way it either reflects or absorbs sunlight and the solar heat it produces. In scientific terms, color affects a material's solar reflectance index (SRI). This is a measurement of how much solar energy a material reflects, which affects the temperature of its surface and how much the material transfers heat around it.
Several factors go into measuring a material's solar reflectance index, but sunlight reflection is the most influential factor. Below is a breakdown of how much sunlight different colors reflect:
Black - Reflects 0-10% of sunlight
Brown - Reflects 10-20% of sunlight
Grey - Reflects 30-50% of sunlight
Light Grey - Reflects 60% of sunlight
Off-White - Reflects 80-90% of sunlight
White - Reflects 90-98% of sunlight
Berridge Manufacturing Company, a manufacturer of metal roofing materials, has provided a great guide with the solar reflectance index for their roofing products. The SRI measurement ranges from 0-1. The closer a material is to 1 the more energy efficient it will be. As you can see, the color makes a huge difference in the SRI, with lighter colors being much closer to the 1 value.
Many environmentalists are now promoting the idea of white roofs because their solar reflectance is far superior to other colors. White is becoming a popular color for metal roofs, which isn't too surprising. One of the main reasons many people choose a metal roof over asphalt shingles is because it's more energy efficient. If you want the most energy efficient roof possible in Texas, then white metal is a safe choice.
Of course, if you live in a climate that is cold much of the year a darker colored roof makes more sense. To cut down on heating needs a black, charcoal grey or dark brown asphalt shingle roof would be one of the most energy efficient roofs.
It doesn't matter what type of roof you have in terms of color and energy efficiency. Even energy efficient roofing materials perform better when they are a lighter color. That's why color plays a significant role in cool roof design.
A cool roof is a roof that is designed to be cooler and more energy efficient by reflecting sunlight and absorbing less heat than traditional roofing materials. Cool roofs can be up to 50 degrees cooler in the summer than conventional roofing, helping to reduce air conditioning use and energy costs.
This is particularly beneficial in areas like Texas where it gets very hot for a good part of the year and the electric grid gets strained from the peak electricity demand of air conditioners. Additionally, cool roofs have been shown to decrease the urban heat island effect, which is a huge plus in Austin.
If you're among the homeowners that prefer the aesthetics of a dark roof but want to save energy, increase comfort and reduce energy bills there's another option. You can make an existing roof energy efficient with a coating.
Cool roof coating helps any roofing material reflect more sunlight by increasing the amount of infrared radiation that's reflected. This is sunlight that can't be seen. As a result, cool roof coating can help dark colored roofing reflect 30-60% of sunlight, getting it close to the reflective level of light grey.
This type of reflective coating can be applied to built up roofs, metal roofs and tiles. However, you have to be careful with asphalt shingle roofs. Coating them after installation can cause problems with moisture retention and void the factory warranty.
If you want to work with a roofing contractor that thoroughly understands how to keep a roof cool in Texas, then contact us at LOA. We also provide general contracting services and can help you improve energy efficiency in other ways. Give us a call to schedule a free onsite evaluation.
Dedicated to excellence, our Austin roofing company ensures quality in every project. Contact our skilled Central Texas roofers for a same-day, hassle-free inspection. Call +1 (512) 375-3654 to book your free inspection.