It was during an Earth Day 2010 event hosted by Sierra Club that I was initially inspired to build a new way to look at our New York City’s rooftops. A speaker chatted to us about sustainability in big metropolitan cities, specifically about how our cities’ rooftops were an untapped resource, and how painting black rooftops a white solar reflective paint could curb climate change.

It’s estimated that implementing a white roof program in 11 large cities could save the U.S. 7 gigawatts in energy usage. That’s the equivalent of turning off 14 power plants.

By simply coating a rooftop with this special white paint, the speaker informed us, we could immediately reduce temperatures inside and out. A simple paint job was a low cost solution to cut carbon emissions, reduce our risk of brownouts, save millions in energy costs, and even save lives. I remember looking over at my friend in disbelief; Why hadn’t we been painting our roofs white this whole time?

The entire way our organization, The White Roof Project, took form was truly serendipitous. Initially the whole point was to do just one project, paint one rooftop white with a group of excited grassroots activists. We met up a few days after Earth Day 2010 to do just that. Our first call was to the Bowery Mission, a nonprofit in NYC serving the homeless and hungry since 1879, to ask them if they wanted us to coat their rooftop.

They agreed to it, and the next few months were spent figuring out how to make good on that promise we made them. It included working with the city government, fundraising for the materials, talking to paint companies and distributors, growing a group of excited volunteers, and learning about all the merits this small act had to offer the world.

Three months later, after receiving a nod on The Daily Show from Bill Clinton, we were ready to tackle our first building. What transpired on that first paint day, when over 100 people came to volunteer, was a watershed moment. I realized this was much more than an initiative; it was the beginning of a movement. It went from being an intrepid group of locals doing a white roof project to an organization catalyzing change.

The statistics are as simple as they are staggering: A roof covered with solar reflective white paint reflects up to 90 percent of sunlight as opposed to the 20 percent reflected by a traditional black roof. On a 90-degree Fahrenheit day, a black roof can be up to 180 degees while a white roof stays a cool 100 degrees, reducing cooling costs up to 40 percent. It’s estimated that implementing a white roof program in 11 large cities could save the U.S. 7 gigawatts in energy usage. That’s the equivalent of turning off 14 power plants.

One thing that amazes me is how much the ambient temperature in a building can change so significantly through this simple action. I can say from experience that the top floor of the buildings we’ve coated are quite cool.

We’ve measured the temperature of a building on a 94 degree day, and inside it was much cooler than the outside air, hovering around 80 degrees. We did not even need to turn the air-conditioning on and I think that’s pretty miraculous. Compare that with the inside of a building with a black rooftop—105 degrees, which feels like an oven.

Since our first project the organization has grown in ways I could have never imagined, and the idea has spread across the nation. Today we build awareness in cities, identify rooftops, organize volunteers to paint them, and evoke real change.

I think it helps that we started humbly and were completely focused on real world results. I think it has helped us keep moving in the right direction quickly, and we’ve grown a great group of dedicated volunteers.

In 2012 alone, we painted over 30 buildings helping hundreds of families lower their energy bills. We also kicked off the first national DIY (Do-It-Yourself) white roof campaign, and we tracked 22 individuals and groups who took to their rooftops that very summer across the United States. This year we hope to inspire and empower a much larger group of people to learn, volunteer, and autonomously evoke change with us.

A White Roof Project is a common sense concept that’s easy to implement and creates tangible change for individuals, our communities, and even globally.

In places like NYC and especially Los Angeles, where it’s warm all year round, it’s a real no-brainer.