There are more than 2.4 million homes for sale in the United States and even more in the foreclosure pipeline, and yet builders are still putting up new houses, according to recent construction data.

Why? It all comes down to the location and condition of existing homes on the market, many of which aren’t appealing or suitable for buyers today, experts say.

“Many dwellings built during the boom years–whether now offered for sale by banks or homeowners wishing to move–are in the wrong locations or badly configured,” Peter Morici, professor of economics at the University of Maryland, wrote in an E-mail. “Much of that housing was premised on cheap energy–far from jobs and requiring long commutes and expensive to heat.”  Read more: