What do home buyers want? More space. For themselves, for their cars, for their kids’ stuff.

A new book published by the National Association of Home Builders, called What 21st Century Home Buyers Want: A Survey of Customer Preferences, finds that the average new construction home buyer wants approximately 20 percent more space than he or she has.

The median size home of those consumers who responded to the survey was 1,770 square feet. They wanted a median of 2,071 square feet in a new home. Unfortunately, they only expected to pay $141,000, just a little more than the $130,000 their current home’s cost.

Perhaps the survey respondents have been visiting new housing subdivisions. According to the NAHB, the median size for a new single family home last year was about 2,070 square feet.

The book is essentially a compilation of a series of surveys. Some 40,000 households were sent an initial questionnaire. A detailed questionnaire was sent out some months later to 3,000 households. Of those, 1,180 responded. The home buyers included in the final analysis were about 44 years old and earned $45,500 per year.

Whether the final analysis is truly representative of what home buyers want in the coming years is a matter best left to statisticians. However, the results are fascinating, as they mirror so many current building trends.

For example, the respondents prefer “large kitchens adjacent to family rooms, with the two rooms visually open but separated by a half wall. They want features like high ceilings and island work areas in the kitchen.”

The study finds that many home buyers would easily trade a living room for a family room and home office space. (Indeed, the precipitous decline of the formal living room makes one wonder how the plastic slipcover industry is doing.)

In addition to wanting four bedrooms (40 percent), a full basement (54 percent) and a minimum of 9-foot ceilings on the first (66 percent) and second (40 percent) floors, today’s home buyer prefers a three-car garage (25 percent), but the majority (54 percent) will settle for a two-car garage.

Although the theme of “bigger is better” runs rampant through the survey, the book reports that some rooms in the house are big enough. While home buyers want bigger kitchens, they’re not willing to trade off other space in the house to accommodate the larger size.

But that doesn’t mean that details aren’t important. The study finds that new home buyers are very interested in the exterior features of their house, and want items such as a front porch, deck or patio in the rear and exterior lighting. Also, dining rooms and laundry rooms are considered essential.

When rating features of a new home, five of those rated “essential were exterior features.” Thirty-two percent of respondents want a lot with trees. Fifty-five percent of consumers prefer a solid-surface material (like Corian or granite) for their kitchen countertop. Eighty-eight percent said a linen closet was essential, and 86 percent said having an exhaust fan was essential as well. Other popular interior items include sound proofing (54 percent), electronic air cleaners (37 percent) and central vacuum systems (34 percent).

Increasingly, new home buyers want ranch-style homes, that is a home on one level. More than half of the respondents prefer to live in a one-story residents, and this preference rises with the age of the head of the household, “but declines with the price respondents expect to pay,” according to the survey.

Of course, all this stuff costs money, and lots of it. But the respondents showed themselves to be thrifty.

Building unfinished space that could be finished later, living farther from shopping and entertainment, living on a smaller lot, longer commute, and fewer amenities were popular ways to keep the cost down. Just 24 percent said they would sacrifice square footage to save money.

One of the most interesting features of the study came in the area of energy savings. Respondents said they were ready to pay the price for the amenities they wanted, but would only pay about $5,000 in the upfront purchase price to save $1,000 per year on their utility bills.

Clearly, new home buyers want a lot for their money. But they recognize that they’ll have to make tradeoffs in order to get a new home for the price they’re willing to pay.