Matt Risinger is exploring one of the coolest houses ever, built by mechanical engineers and some of the best builders of their specialties. He visited a house that is so efficient, it's considered to be in the top 10 most energy efficient homes in the US. Built 5 years ago, the owner has never had to pay for a utilities bill, not one penny! The house is beautiful, and looks normal from the outside. It's a certified passive house, one of 2 in MA. A passive house has some of the strictest building and air tightness standards in the world, in order to even be certified, the house has to be approved by a 3rd party. The idea of a passive house is that the house can lose power, and it can completely maintain itself without power. In fact, it was tested, and a passive house lost power in the winter, and over the course of 5 days the inside of the home decreased by 10 degrees only. Pretty amazing technology here. 30% of the house is glass, and 60% of the house's heat enters through the windows as sunlight leaving only 40% for the owner to pay. You're not going to want to miss this video!