August 28, 2014

The Benefits and Controversy of White Roofs

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 in order to offset it.

white roof

So, in other words, installing a roof that is white or “reflective” helps save 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 by 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. (Check out this interesting analysis from Treehugger.com.)

Another question is the overall environmental benefit of reflective roofs  – and whether they actually do slow global warming. A Stanford study published last year found that the heat being reflected from white roofs may actually exacerbate climate change by contributing more heat to the atmosphere and absorbing more emissions. Earlier studies have suggested that whitewashing roofs can have a cooling effect.

If you do decide to install a white roof on your business or home, make sure you do some research about costs and options in your area and get at least a few bids from different contractors. There are several different types of reflective roofing materials.

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.


White Roof Photo via Shutterstock

7 Comments ▼

Kelly Spors


Kelly Spors Kelly Spors is a former small-business and entrepreneurship reporter and blogger for The Wall Street Journal who has also written for Yahoo!, Entrepreneur, NFIB's MyBusiness magazine and The New York Times. Kelly is now a freelance editor and writer based in Minneapolis and has previously managed communications for an environmental non-profit that helps businesses find ways to be greener.

7 Reactions

  1. I can personally vouch how the color of a building can make a huge difference in heat absorption. Our house used to be a fairly light color and we painted it a much darker color a few years ago. While we didn’t do anything to the roof, painting the sides of the house sure made it heat up more in the summer. Yes, the house looks a lot better being a darker color, but man, it sure causes more electric use.

    Oh, did I mention that we live in Phoenix, so it is no wonder we saw this outcome.

  2. Not to rain on the parade here, but if the goal is to stop absorption of the sun’s energy shouldn’t we be more focused on roads and parking lots? They are much larger in terms of square feet.

  3. I agree with Robert, it seems like if we truly want to make a difference we should focus on the bigger picture. Making a big show out of installing a white roof seems just that, a show.

  4. Earl McClintock, RRO

    It is a complex question here in Nebraska. Here we have more heating degree days than cooling degree days which would point to the need for a darker roof. Also, we are installing more insulation at around R-24 average. Does the color of the roof deminish as the R-value goes up? What is the cost per sq. ft. per year for the tax payer for public buildings? The “heat island” effect is not of much condern here where we have miles and miles of green grass and corn. Anyway the experts say it is about a “wash” here in the center of the country.

  5. We can’t forget that using trees to provide shade also helps to keep the temperature down.

  6. This is huge the benefits are great. My roofing company is now an independent participating contractor in the energy saving program this summer in Florida with FPL.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>



Compare your business to the industry - Try our new tool