That big, fancy house down the street -- is it a showplace? Or a showoff?

You might call it a McMansion, the nickname for a supersized trophy home. Minnesota appears to be a hotbed. A recent Census Bureau survey ranked us fifth nationwide for our percentage of new homes with four or more bedrooms, and "McMansion" debates are being waged in city halls across the Twin Cities.

But it's a lot easier to deploy the "M" word than to define it.

"The term refers to something overscale and cheesy," said John Archer, architectural history/cultural studies professor at the University of Minnesota. "Of course, overscale and cheesy are both in the eye of the beholder. You can't define it. It's like pornography; you know it when you see it."

Unless you happen to live in it. Then you might not even realize that your home is an ostentatious cliché.

"I've had many people ask me, 'Do I live in a McMansion?'" said architect Sarah Susanka, author of "The Not So Big House" books. "That's tricky to answer."

Suburban subdivisions are rife with McMansions, but you're not likely to see them described that way in a sales brochure. "No. I've never used that term in marketing a listing," said Cindy Welu, a Remax agent who works in the southwest suburbs. "I don't get a real positive vibe from the word."

The moniker has morphed since it emerged in the late '80s, Susanka said. In 1998, when she was writing her first book, McMansion referred to a big exurban home that looked good from the street, but wasn't well built. "They were homes built for speed and a quick sale, as opposed to care and quality of design," she said.

But in recent years, the term has become associated with teardowns in established neighborhoods and new homes that dwarf surrounding ones -- and raise neighbors' ire.

"Often they're out of proportion to the homes that are already there," Susanka said. "That's the thing that seems to offend people the most. I've seen some beautiful architectural masterpieces, but the neighbors are still upset."

Susanka isn't opposed to teardowns. "It's going to happen when a house is dilapidated or not fitting the needs of today." But often owners pick a plan from a book, without considering the site, she said. "They're unaware until it's built that it's way out of proportion with the neighborhood and that the very thing they love about their neighborhood will be destroyed by what they're building."

New houses in old neighborhoods don't have to scream "McMansion," she said. A house can harmonize with smaller homes if its roofline, window size, frontage and other elements are in proportion to those surrounding it.

Context is key, agreed Archer, author of "Architecture and Suburbia." "If you have a street of little bungalows and you put up a big two-story house, it's a McMansion."

Eclipsing the neighbors

The issue has been hotly debated in Edina recently, where several residents of the South Harriet Park neighborhood urged the council to impose a moratorium on teardowns.

"A McMansion is forever; a moratorium is temporary," said Brian Belanger, who calls a spec home being built on his street a "monster house." "I have no objection to them in an appropriate neighborhood. But this is a little, old traditional neighborhood. They're tearing down 1,600-square-foot homes and replacing them with 5,000-square-foot homes. There's practically no yard. It boils down to visual mass, and the light and view that it blocks. The neighbors will live in perpetual eclipse." (The builder of the home declined to comment.)

Edina is considering an amendment to limit new homes' floor-to-lot ratio, said Cary Teague, planning director. The city formed a task force three years ago and recently developed "massing" guidelines.

Greenwood, too, is working on an ordinance to limit mass-to-lot ratio, as the small cabins that once dotted its Lake Minnetonka shoreline are upgraded to large year-round homes. They aren't McMansions, said Pat Lucking, who heads the city's Planning Commission. "But some mansion-ization has gone on. There are probably a dozen houses that are too big for their lots. We don't currently have anything on the books to regulate that, and people took advantage."

Big new lake homes also are riling property owners in Dellwood, where Rhiannon O' Connor was one of several who tried, unsuccessfully, to stop her next-door neighbor from replacing an existing house with one that's twice as tall and three times as big as her own 3,000-square-foot house. "It will block our light and sunsets and is way oversized for the lot," she said. (The owner declined to comment.)

But some see upsizing as just part of a cycle.

Neighborhoods need to be "refreshed," said Todd Shipman, a Sky Sotheby's real estate agent. "Change is hard for people, and it's always nice to respect your neighbors, but my sense is that some neighbors are overreacting." That said, "There are ways to achieve quality of life without a lot of volume."

McMansion blight ahead?

Big houses are nothing new, of course, but there are definitely more of them than in decades past. Average square footage for new single-family homes continues to creep upward, according to the National Association of Home Builders, reaching 2,469 in 2006, compared with 2,434 the year before and 1,700 in 1976.

Many people are building more house than they need, said Tom Fisher, dean of the College of Design at the University of Minnesota. "I cringe when I go to the suburbs and see excessively large homes with wasted space. People think they can't afford an architect, but a good architect will talk you out of doing unnecessary things. People used to raise a family in 800 square feet. Now they feel deprived with under 2,500 square feet -- 5,000 square feet is absurd."

Model home tours have fueled the bigger-is-better aesthetic, Susanka said. "A big living room with a vaulted ceiling may look cool with 200 people walking through it, but when it's just you and your husband, you may not like it."

However, some see a new aesthetic beginning to emerge. Archer has noticed a shift in the way new developments are designed and marketed. "If you read the promotional materials, they're increasingly about 'community.' Ten years ago, it was about making a statement." Big houses will continue to be built, but in a less showy way, he predicted. "They may still have a two-story foyer, but they won't broadcast that from the street with a cathedral window."

And ultimately, changing demographics will push supersized homes out of favor, said Arthur C. Nelson, director of the Metropolitan Institute at Virginia Tech. With baby boomers aging out of their child-rearing years, there soon will be many more big single-family homes than buyers.

"Just like the olden days, when huge Victorian homes were converted to apartments, that's going to happen in the exurbs," he said. "The market will demand it. They'll be occupied by a different kind of household; my best guess is multiple-family, lower-income households. Today's McMansions will be the affordable housing of the future."

Kim Palmer • 612-673-4784