BOULDER, Colo. (AP) - Boulder County officials are recommending a slower rollout of building codes that would require all new construction in unincorporated Boulder County to be ”net zero’ for energy use by 2022 after several board members expressed concern over the costs associated with building a home that produces as much energy as it consumes.

Chief building official Gary Goodell recommended that the standard be applied instead only to homes 5,000 square feet or greater. Now, the standard applies only to homes 6,000 square feet or larger, and some supporters would like to see it apply to even smaller houses.

Sustainability examiner Ron Flax said county staff members felt that energy goals were ”moving faster than the marketplace could handle.’

”I’m not sure the market can handle it now,’ board member John Matthews said in response.

Matthews was one of several board members who expressed concern over the costs associated with building a home that produces as much energy as it consumes.

All costs associated with building a net-zero home are higher, though experts disagree on just how much, the Boulder Daily Camera reported (http://tinyurl.com/qf56wl8).

Sustainable architect Thomas Doerr said building a home to be totally energy efficient typically adds 15 percent to the cost. For a Boulder County home with 4,000 square feet that could add another $100,000.

Flax and others said net-zero homes can and are being built for market rates around the state.

Board members and city staff members said more study is needed.

”I’m all for sustainability, but I think we need to understand the cost of construction given the current housing climate in Boulder County,’ Matthews said.