BY: ROB HOFFMAN
When I first heard about urban rooftop gardens, I thought it was one of the coolest building-design ideas of all time. They’re good for the environment and provide the practical benefit of locally grown food. However, a study published in the Energy and Buildings Journal recently claimed that white roofs—simply painting your roof white—may better serve the environment.
According to research from the Lawrence Berkeley National Laboratory, the reflective quality of white roofs allows it to fight climate change at a much higher degree than green or black roofs. White roofs are “three times more effective than green roofs at cooling the globe,” according to the study. The study also examined economic factors like energy savings (heating and cooling) and roof maintenance and concluded that white roofs possess an attractive economic benefit.
The method behind the white roof is simple: reflecting sunlight back into the atmosphere and preventing a significant amount from reaching ground level. So long as you remain under your roof, you avoid the sunlight reflected by it and therefore stay cool.
However, Mark Z. Jacobson and Ten Hoeve from Stanford University preformed a number of studies that poke holes in LBNL’s research. Their data suggests the possibility of the reflected sunlight hindering the cloud formation that would’ve blocked out the sunlight in the first place. Clearly, a lot more research needs to be done before declaring white roofs superior over their green counterparts. Especially considering the added value of the green roof to grow food and provide a pleasant woodsy aesthetic. Green roofs also pose a number of significant economic and environmental benefits, reducing rainwater runoff and improving the home’s insulation.
As it stands, it seems both white and green will benefit the environment and help reduce climate change. At the least, it’s just nice to know that there’s a lazy alternative to green roofs. So, if your heart is green but your thumb is not, go for a white roof. Alternatively, a green roof requires more upkeep but also provides a much greater personal reward—both in food and self-fulfillment. Either way, Mother Nature’s got your back.