Reporting from the 2011 International Builders Show, Erica Christoffer for HouseLogic

What do home buyers want today and in the future? The answer: smaller, more energy-efficient homes.

The average size of a new single-family home in 2010 was 2,377 sq. ft., down from 2,438 sq. ft. in 2009 and down from the peak of 2,520 sq. ft. in 2007 and 2008, according to U.S. Census Bureau data presented yesterday at the International Builders’ Show in Orlando by Rose Quint, assistant vice president of survey research for NAHB.

And the trend will only continue, Quint said, with the 2015 new home size currently projected at 2,150 sq. ft. with fewer bathrooms and smaller garages.

It’s hard to say whether home sizes will decline to 1970 levels of 1,500 square feet. But Quint says she believes smaller sizes are here to stay based on demographics. The U.S. population was 310 million as of April 2010. That’s expected to rise to 322 million in 2015 and up to 422 million by 2050. The population is also getting older and more diverse. In 2010, 25% were over the age of 55, which is expected to grow to 31% by 3050.

This rising segment of older home owners who won’t want to care for a huge space, Quint said, and then you have Generation Y buyers who are very energy conscious. “People are coming to realize, ‘Let’s buy what we need,’” said Quint.

The Census Bureau data matches NAHB’s findings that builders expect to build smaller homes with more green features in the next five years. Low-energy windows, water-efficient features, engineered-wood beams, joints, or trusses, and Energy-Star ratings for whole home are expected to be more prevalent.

Builders also expect an increase in living room size as well as more planning for universal design features with homes more easily adaptable for future improvements.

Jill Waage, executive editor with Better Homes and Gardens, also presented her magazine’s 2011 consumer preferences survey, which was taken the first week of December. According to Waage, the top three improvement priorities home owners want were a laundry room, additional storage, and a home office.

“The connection to outdoor living space is also really important,” Waage says.

Other trends included in the Better Homes and Gardens study: built-ins, media space for flat screen TVs and gaming systems, and areas wired for technology. Buyers also want combined kitchen, family room, and living room open space. Universal design features, she said, will be incorporated in much more subtle ways.