City planners and politicians in Boulder, Colo., are debating whether size and sustainability can live together under the same roof, and if they have their way, homeowners may soon face a limit on just how big their homes can be.

The Boulder City Council is considering an ordinance that will limit “floor-area ratio” calculations, which would define what percentage of a building lot can actually be built upon.

“It’s not a cap on the square footage, it’s a cap on the space in the lot,” explains Ryan Morgan, a staff writer for the Boulder Daily Camera who has be covering the home-size debate.

“This is the third time this particular debate has come up this decade,” says Scott Rodwin of Rodwin Architecture in Boulder. Every time the issue has come to the forefront, Rodwin says it has been a case of “a minority of people shouting about it loudly.”

Boulder isn’t the first city to propose limiting the size of homes. The City Council of Austin, Texas, passed a similar measure in 2006 to mixed reviews. But if the Boulder ordinance passes, don’t be surprised if it leads other local governments currently weighing in on sustainability to follow suit, or at least consider similar measures.

As expected, the proposal has sparked quite a debate. On the Daily Camera comments page, some readers labeled city leaders “communists,” while others find fault with those who want to build oversized “McMansions.”

Multiple factors have played a role in the emergence of this issue, but growth and relative strength of the Boulder housing market are among the chief drivers. Modest homes that have sat for decades on modest sites are now being demolished to make way for newer and much larger (and more expensive) replacements. City leaders say some of the new homes are too big and threaten the character of older neighborhoods. And as newer, larger homes are being built, less affordable housing is available.

And then there is the age-old debate of if it’s bigger, can it really be green?

“I would say that building bigger definitely uses more resources, and if you consider the embodied energy it takes to build a larger house, for example, there is no doubt an equally sized green house would be more environmentally sound,” says Julie Herman, executive director of the Boulder Green Building Guild. “That said, if a larger house is built very energy efficiently and uses products that are both renewable and local, or at least as local as possible, it could have a lesser impact overall than a smaller standard house.”

Plus, Rodwin says newer homes are going up to replace post–World War II homes that lack insulation, use single-pane windows, and rack up $400-a-month utility bills.

According to Rodwin, the majority of environmental issues brought up in the Boulder home-size debate are about education. For example, through the Boulder Green Points program, builders must send the deconstruction materials to a construction waste landfill where they can be used for future projects. Rodwin adds that the city has plenty of programs in place that address other environmental issues. And, although he lives in a small home, Rodwin, like many others in Boulder, doesn’t want an ordinance to determine just how big his bedroom can be.

“I don’t believe it is the role of the government [to dictate home size],” Rodwin says.