At the Frye household, money is tight.

So when it comes to energy costs. Bobby and Ashlee Frye have to be responsible.

"Every penny counts," said Bobby. "When you just buy a house, the first thing you think about are your bills. You try and save on every penny possible."

"We're very careful about turning the lights off and keeping the heat down low," said Ashlee.

But each year, unsuspecting homeowners spend hundreds of dollars on wasted heat -- heat they don't even know they're losing.

Gary Nordeen with the Washington State University extension energy program says leaky ducts can account for almost a third of your heating bill.

"It's a huge problem. In the United States, they estimate energy loss from leaky ducts at $10 billion annually," said Nordeen. "Say $20 to $30 out of every $100 you are spending on energy to heat the house is leaking into the cross space or somewhere else that you don't intentionally want to heat."

So with the Frye's permission, we setup their house to demonstrate how and where heat leaks, clogging the vents with Styrofoam blocks and using a fog blaster to represent the heat.

Within seconds, the fog entered the home's heating ducts.

"That's a lot of leakage," said Nordeen.

It began to seep out of the Frye's furnace and into their garage. We even noticed heat leaking from under the crawlspace and eventually to the outside of their house.

"About a third of your energy bill is going somewhere you don't want it to go," said Nordeen.

Nordeen estimates that there are hundreds of thousands of Washington homes with leaky ducts. He cautions homeowners to avoid using duct tape to clog the leaks -- instead, use a mastic duct sealant.

"You take it and smear it on the ducts - on the seams of the duct so when it dries it's flexible," said Nordeen.

The Frye's home is less than 10 years old, but they still found holes.

"They hope by fixing the leaks, they will save 30 percent on their energy costs.

"That's a car payment. That's a house payment," said Bobby.

The Washington State Building Code Council is now pushing for changes to the state's energy code. They want to pass legislation which would require mandatory duct testing, and in turn, limit duct leakage.