Residential construction, remodeling, moving, gardening and furniture buying add up to about 20 percent of the country's gross domestic product — which is why the upward momentum in housing, which continues to gain steam, is such a powerful boost to the economy.

But it's not just that. By year end, U.S. homes will collectively be worth $3 trillion more than they were at the bottom of the market. "And that will provide a significant boost in consumer spending" — $100 billion in extra spending this year, to be exact, says one expert.

(READ or LISTEN to the story at NPR News)