Catherine Mohr began her career as an engineer, and for her mid-career break, she went to medical school, where she invented a brilliantly simple device, the LapCap, that makes laparoscopic surgeries safer. Mohr now oversees the development of next-generation surgical robots and robotic procedures, as the director of medical research at Intuitive Surgical Inc., where she’s the clinical design leader for the DaVinci Surgical Robotic system. Needless to say, she pays attention to details and makes decisions based on sound evidence.

She applied this same mentality to the process of building a green home, and that’s what this eye-opening and entertaining TED Talk is about.

She opens with this: “First of all, I’m a geek. I’m an organic food-eating, carbon footprint-minimizing, robotic surgery geek. And I really want to build green, but I’m very suspicious of all of these well-meaning articles, people long on moral authority and short on data, telling me how to do these kinds of things. And so I have to figure this out for myself. For example: Is this evil? I have dropped a blob of organic yogurt from happy self-actualized local cows on my counter top, and I grab a paper towel and I want to wipe it up. But can I use a paper towel?”

Watch the video to hear what she learned about embodied energy and how the choices that matter are not always the ones you think.