FORT CAMPBELL, Ky. -- After a year of work, Fort Campbell has finally opened its zero-energy houses to residents.

Campbell Crossing held an open house Wednesday morning to show off the homes, which are the first two of their kind on a military installation.

"Two zero-energy homes will be compared to two base-line homes that have been equipped with the same monitoring systems and over the next four seasons we gather data from these homes and build the second part of our project," explained Patrick Tahaney, Campbell Crossing development manager. "Together we hope to build a model for zero energy. A model that will not only be used by Actus Lend Lease projects, but a model that can be used by the construction industry as a whole and the Department of Defense."

Despite their name, the two homes are not designed to be entirely self sufficient. Instead, they are built to be net-zero - they are designed to use 54 percent less energy than a regular duplex on Fort Campbell and they produce as much energy as they use.

The main way the houses manage this is through 34 solar panels on the southern facing portion of the roof. During the day, the panels collect enough energy to power every device in the house along with excess that is sent out to the electric grid. When the sun goes down, the houses pull energy back from the grid.

Also on the southern facing wall, the roof eves have been extended eight inches to provide more shade and the windows have been equipped with retractable awnings for when the radiant heat becomes too great. The awnings are self-deploying, but that can be overridden to allow residents control.

The houses are heated and cooled using geothermal energy. Because the air being pumped in from beneath the earth's surface is already at a constant temperature, it only has to be heated or cooled a few degrees to keep the homes comfortable. Normal heating and cooling systems have to alter outside air - raising it 20-30 degrees in the winter and dropping it 20-30 degrees in the winter.

"These houses are the Army's first zero-energy homes, they represent the Army's and Actus Lend Lease's commitment to sustainability, energy efficiency and good stewardship of our natural resources," said Col. Perry Clark, Garrison commander.

"In the past, energy has been a side conversation for the Army.

"We've listened to public service announcements reminding us to turn off our lights, and gave lip service to energy reduction measures in our daily activities, but our culture was not a culture of conservation. We the Army can no longer be casual with our energy consumption. We are in the middle of a shift from a culture of mission-focused consumption to a military culture that includes sustainability as a means to increase our defense capability."

Actus Lend Lease screened all the families on their NCO housing list to find four families with normal energy consumption habits to help them measure the efficiency of the homes. In the two baseline homes are the Shorters and the Joneses. In the Zero Energy homes are the Allisons and the Aguilars.

"We're really excited about moving in, it's a great program to be involved in considering it's the first in our country," said Laura Allison. "As a military spouse, we move a lot so it's nice to have a new home. And they're going to help us to better understand what kind of energy we use as a family anywhere we live, so it's a great tool."

"We're really excited, it's a great experiment and we're just happy to be a part of it," said Chastity Aguilar. "We haven't gone in ours yet, we've gone in Laura's, so the kids are excited to go in ours and see their actual rooms."

The homes were kept vacant for the open house, but the families are expected to move in this week.