The Benefits and Controversy of White Roof Coatings
Much ado has been made in recent years about the benefits of installing white or “cool” roofs. The idea: Light-colored materials reflect heat, while dark roofs, such as those made of asphalt and tar, absorb heat, driving up air-conditioning consumption to offset it.
In other words, installing a roof that is white or “reflective” helps in saving energy and money.
Energy Secretary Steven Chu has pressed Americans to install cool roofs on their homes and business, even committing his own department to making all its new roofs white.
But is the hype about cool roofs legitimate?
Should you consider one for your business?
First, the net energy savings generated by white roofs compared with dark roofs depends partly on where you’re located. White roofs seem like no-brainers in warm climates like Phoenix, Las Vegas and Miami, where they can keep air-conditioning bills in check year-round. States like California even now mandate white roofs on commercial buildings.
In cooler climates – think Detroit or Toronto – the issue is less straightforward. While white roofs may shave electric bills in hot summer months, studies suggest they increase winter heating bills. The question is just how much. Some scientists say white roofs can increase heating costs more than they save on A/C costs. Scientists at Lawrence Berkeley National Laboratory dispute this, saying the electricity savings of air-conditioning has found to outweigh any negatives even in cool cities like Minneapolis.
The very important factor is reflective roofs overall environmental benefit and their impact on slow global warming. Last year, Stanford published a study which claims that the heat from white roofs really has some effects on climate change – more heat is absorbed to the atmosphere, so more emissions is also absorbed. Some studies before claimed that whitewashing roofs can have a cooling effect.
That’s why is very important to research all costs and possibilities in your area of living before installing a white roofing system. You should collect several options and then decide which one is the best option and has more benefits. There are many different reflective roofing material types.
Also look into incentives available to you. Some states offer rebates for installing white roofs, as do some electric utilities. You can look up incentives at DSIRE.
Lots of Alternatives for Black Roofs!
Dark roof’s surface can be warmed up to 180° during a sunny day. A hot roof has a great impact on the inside’s structure, a situation welcomed in Minnesota in January but is more likely to occur in Texas in August. Heat goes inside the structure and often still rises. It elevates the temperature inside the structure, and air conditioning inside your house becomes a must-have option.
Besides that, the roof also keeps sending a part of the heat back to the atmosphere, and in densely populated areas creates so-called „heat islands“. Dark surfaces absorb the heat from the sun, but also its rays, what leads to lower Earth’s solar reflectance. That is called albedo and has an impact on climate change also.
Lately, a movement toward white roofs occurred. Energy Secretary Steven Chou, also a winner of Nobel Prize in Physics, lately spoke about the importance of white roofs and its impact on the environment.
White roofs are a great solution for reflective purposes because they are also very smooth. Several tests run by Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, and the Florida Solar Energy Center, examined that black or dark shingles reflect 5-9% of the sun’s rays and their roofs reach between 76° to 90° above the air temperature. Usually, asphalt or white shingle roof has a solar reflectance of 25% with a 70° temperature difference. It also has a high-grade white tiles or shingles (white clay, concrete, or fiber cement) score at 35% and 60°.
To Learn More About White Roof Coatings….
Contact our White Roofing Systems Coating Team here at White Roofing Systems to get the full details about how roof coatings can help your commercial roof!