The millennial generation is poised to make a significant impact on home design with their strong preferences for energy efficiency and smart home technology; comfortable, workable kitchens and more casual spaces, according to speakers from the National Association of Home Builders (NAHB) and Better Homes and Gardens' press conference on housing preferences for millennials, Gen X, boomers and seniors at the NAHB International Builders' Show in Las Vegas.

But first, they have to move out of their parents' homes and into a place of their own, said Rose Quint, NAHB's assistant vice president for survey research. In 2015, about 15% of adults ages 25-34 lived with a parent, about 3% more than the highest share between 1983 and 2007—12%. That translates into 1.3 million people who normally would be out there, forming their own households, demanding their own units either as buyers or renters.

Quint had anticipated that new mortgage programs and looser mortgage insurance requirements unveiled a year ago would have led to an increase in consumers buying homes for the first time. But a look at the size of the typical new single-family home in 2015 found the opposite: home sizes grew to an average of 2,721 square feet, the highest yet, and an indication that the new-home market continues to be dominated by move-up buyers, rather than first-time buyers.

Before we see that expected pullback in square footage and price, we're going to have to see a significant return of the first-time buyer, who is more likely to buy a smaller home at a lower price point, added Quint.

This year, home buyers of all ages say they are looking for homes with separate laundry rooms, energy-star appliances and windows, exterior lighting and a patio.

What they don't want are rooms with cork flooring, elevators, pet washing stations, expensive outdoor kitchens and fireplaces and two-story entryways and family rooms. And their countertops should be granite, but never laminate, according to a Fall 2015 survey of potential buyers.

In terms of house type, buyers want a detached, single-family home: 65% of all buyers and 68% of millennials expressed that preference. That number rises to 72% with Gen X (born between 1965 and 1979) but falls somewhat to 55% with those born before 1945, Quint said.

Jill Waage, Better Homes and Gardens' brand executive editor, echoed Quint's findings on preferences for well-equipped kitchens and casual, comfortable living spaces—especially outdoor living rooms, where millennials want to entertain their families and friends.

“What's important about this generation is their comfort with technology,” according to Waage. “Millennials are leading the way on this. They are the first generation to walk into homeownership with a smartphone in their hands."

Their home improvement preferences center on home organization and workspaces, as the separation between working in an office and telecommuting continues to blur.

"This generation is searching out ideas, following bloggers, and creating Pinterest boards with their preferences,” Waage said. "They've already curated their dream home online, saving it on their boards so they can [be ready] when the day finally comes."

The survey results are also important to home builders in the 55+ market, according to David Peskin, president of Reverse Mortgage Funding (RMF), which sponsored the NAHB study on consumer preferences.

"The results of this important survey shed light on the buying preferences of older Americans, and confirm that an uneasiness over finances is one of the primary reasons they are hesitant about relocating to a new residence that better suits their needs," he said. "At RMF, we are committed to helping home owners age 62 and older meet their financial needs, so this data will be informative to the way we educate consumers about our Home Equity Conversion Mortgage for Purchase (H4P) product."

For more information, visit nahb.org.