Knightdale, N.C. — The average size of a single-family home in the U.S. has jumped 150 percent in the past five decades, and some observers blame the desire to super-size the American dream for the current mortgage crisis gripping the nation.

In 1950, the average home size in the U.S. was 983 square feet. By 2006, the average size had moved to more than 2,430 square feet, according to the National Association of Home Builders.

In Wake County, the growth spurt hasn't been as dramatic. The average size of a home in 1950 was 1,418 square feet, and it was up to 2,278 last year, according to the county planning department.

"Three bedrooms, a kitchen and a living room are just not doing it for people anymore," said Shanta Jackson, a real estate agent with Realty Executives Parrish in Knightdale. "Everybody's doing it, and I think it is because people want more space. No one wants to feel claustrophobic."

Jeremy Haynes and Lynn Whitney said they enjoy the spacious master bedroom in their new 3,800-square-foot home in Knightdale. The couple recently added a fun room with a pool table and arcade, and they plan to add another room upstairs for their children.

"I think it's important in the fact that you're not stumbling over each other, especially when you have three kids," Haynes said. "I think 3,000 (square feet), for us, it's a pretty good size. For some, it might be too big, and for others, it might not be big enough."

In a new book, author Daniel McGinn dubs the push for ever-bigger homes "house lust." Some home buyers have "an irrational desire for cathedral ceilings, mud rooms and natural stone counter tops," he said.

"I have seen people in Raleigh with house lust," Jackson said, adding that she believes the condition spawned the nationwide mortgage meltdown. "The whole allure of sub-prime (mortgages) was getting a mortgage for a house and having a lower payment. So, bigger house, smaller payment. sounds like a winner."

Jackson said she thinks "house lust" with withstand the lending crunch.

"People are still lustful, but I think they're being very careful," she said. "What I'm hearing is, 'Hey, this is my price limit. But I want the biggest house for that price.'"