After decades of use in Europe, a new type of energy efficient homes is starting to catch on in the United States. Known as passive homes, these buildings are designed around the concept of an airtight, completely insulated house that creates almost as much power as it consumes, thereby dramatically increasing energy efficiency. In other words, this solution enables homes to stay warm without having to use big furnaces and stay cool without central air conditioning. With energy efficiency growing increasingly important to American homeowners, more developers and consumers are starting to turn to passive homes.

The idea isn't entirely new, though. As Katrin Klingenberg of Passive House Institute US – an Illinois-based certification, research and consulting group – tells Philadelphia's The Inquirer, the concept actually originated in the United States.

"People associate the passive house movement with Europe, but it comes out of the (American) oil embargo and energy crisis in the 1970s," said Klingenberg. "Then political change happened, (energy) prices came down … but in Europe that didn't happen, so they had reason to continue the research."

There are approximately 20,000 passive homes throughout Europe with fewer than 100 in the United States, but that's set to change as it has begun to trend in Pennsylvania up to New England, even stretching south to Louisiana and west to Arizona.

Passive homes are built with thick roofs and walls and highly insulated windows and frames. These eco-friendly materials keep houses comfortable to live in while using 90 percent less energy than traditional homes, according to Passive House Institute US.

Pennsylvania residents interested in reducing their energy use should schedule an appointment for a home inspection. These contractors can perform an energy audit that measures your house's level of power consumption and explain what you can do to change it.