Americans are super-sizing their homes in ever-increasing numbers. In fact, the average American home has doubled in square footage since the 1950s, while family size is down from 3.7 people at the height of the baby boom to just 2.3 members per household. The result is that U.S. homeowners now have three times the living space per person as their grandparents' generation.

How is all of that extra space being used? The new "essentials" in larger homes include media rooms, separate rooms for each of the kids, great rooms, gourmet kitchens, bathrooms adjoining each bedroom, game rooms, and offices. In effect, the home becomes like a community -- you can get all of your needs met there, with very little interaction required with your larger community. That is precisely the point, say some big-house owners, who point to Sept. 11 as a turning point in American culture. The big house becomes like a fortress, an illusion of protection against a larger and more unpredictable world.

Ask other folks why they think we Americans love our big homes and you'll get still more varied answers. Pragmatists may say that it is all relative; we continually strive to top ourselves, not to mention the Joneses, and end up with houses that dwarf the land surrounding them. Critics may say we're a greedy culture that is careless with the environment. Others may take a softer stance, arguing that we're simply trying for a better life than the one we had growing up.

Whatever the reason, the big house will dot the American landscape for many years to come. But is it for you? Here are some of the downsides to the big house:

1. Big houses are less environmentally sound. Large homes use more building supplies, require more energy to heat and cool, and create more storm runoff that places more demand on drains and waterways. Despite more energy-efficient ways of harvesting building materials and heating and cooling homes, bigger homes (even well-insulated ones) tax our resources much more strenuously than their smaller counterparts. 

2. Wasted space abounds. Just because there are multitudes of cool spaces in these large homes doesn't mean anyone is using them. How many of us actually spend most of the time in our homes in just one or two rooms? And yet, we pay for utilities, upkeep, and furniture to maintain all of these unused spaces.

3. Too much living space has a negative impact on family cohesion. "Too big" is all a matter of perspective, of course, especially when you're talking about psychological well-being or optimal family functioning. But some psychologists have postulated that there's a negative impact on family togetherness, problem-solving, and communication skills when everyone has their own individual spaces to which they can escape. Aaron Spelling's 56,000-square-foot French chateau beat out the White House by 1,000 square feet, but it didn't seem to do too much for family togetherness (if you believe the entertainment rags).

4. Larger houses may cause financial hardship. You may be able to get a big loan for that McMansion, but can you pay it back? Mortgage lenders determine how much money you qualify for using a rosy scenario that doesn't take into account emergencies, college savings, or other long-term goals. Purchasing the largest home you qualify for without thinking of other pressing financial concerns can leave you vulnerable to foreclosure or even bankruptcy.

Not sure how much home you can really afford? Your best bet is to write down all of your current financial obligations, along with your long-range goals. Create a budget that details how much money you will need to set aside monthly to meet all of these goals. Be sure to factor in an emergency fund.

No one can tell you what version of the American dream should make you swoon, but remember that when is comes to home-buying: bigger isn't always better. Sometimes it's just too darn big.

This article is adapted from the Motley Fool Green Light "Money Answers" archive, which features more than 100 articles on personal finance topics such as taxes, credit, and beginning investing, organized by subject and life stage. For access to this content -- plus the current newsletter, back issues, members-only discussion boards, and advisor blogs -- take a free 30-day trial today!

Elizabeth Brokamp, a.k.a. "Mrs. Riches," is a Licensed Professional Counselor who loves her brood-to-square-footage ratio. Have your own opinions about what makes a home the right size? Weigh in by sending her an email.