SUN VALLEY — Backers of a plan to limit the size of houses in this resort area to less than 12,000 square feet — and smaller on hillsides — say they want to preserve open space.

But critics say limiting the size of houses would infringe on property rights and could end up reducing property values.

“The intent in my book is to preserve the integrity of Sun Valley,’’ Sun Valley Mayor Jon Thorson said at a Planning and Zoning Commission meeting last week.

But Wally Huffman, general manager of the Sun Valley Co., said houses less than 6,000 square feet along a new golf course the company is building would “shrink’’ property values.

“This plus a whole plethora of other things you are involved with is a travesty,’’ Huffman told commission members, the Wood River Journal reported. “Your hillside ordinance will limit the size of houses we can build.’’

He said potential buyers told him they want to build houses between 7,500 and 9,000 square feet.

Commissioners voted to limit home sizes at the meeting. Public comments are being taken and the City Council will consider the matter at a meeting this month or next.

In favoring smaller luxury homes, Sun Valley is following the lead of other Western resort areas such as Jackson Hole, Wyo., Telluride, Colo., and Aspen, Colo.

“People say Colorado is destroyed,’’ said David Brown, one of the commissioners who voted for the size limits. “Sun Valley is gorgeous because when you look around, you see trees. You don’t see lights coming on in windows where no one is home. This place is special.’’

A survey by the Sun Valley-Ketchum Chamber and Visitors Bureau found that 50 percent of homeowners in the area don’t live in their homes year-round.

The proposed size restrictions also factor in slopes, and consider total floor area rather than a home’s footprint.

“During the comprehensive plan hearings, people repeatedly told us 10,000 square feet was too big,’’ said Virginia Egger, the city administrator.

Egger said the average house in Sun Valley is 3,500 square feet, but some recently built houses are 14,000 square feet.