Houses in Blaine County will need to be 15 to 75 percent more energy efficient than national building code requires, due to a decision made Tuesday by county commissioners.
Commissioners voted to approve the 2009 International Energy Conservation Code, which regulates energy-efficiency standards for new homes. However, the county also approved amendments that go beyond the code's standards.
"This is the direction the whole nation is going," said Commissioner Angenie McCleary. "It may be a challenge, but I believe it's possible."
The amended code would require most new construction to comply with certain Home Energy Rating System scores, which determine how energy efficient a home is and are affected by standards that include orientation, number of occupants and even the size of the windows.
Homes smaller that 2,500 square feet may comply with county code by meeting the international code's standards and including approved above-code furnaces and water heaters and being more airtight.
Houses certified through third-party energy efficiency standards such as the Leadership Energy and Environmental Design or National Green Building Standards would be exempt from the amendments.
The county code is set to go into effect on May 1. Commissioner Tom Bowman said the delayed date would give builders and architects time to adjust to the new code.
What is HERS?
The Home Energy Rating System is a scoring index that determines how energy efficient a home is.
A home's score is determined by comparing the energy consumption of the proposed or existing home with a "reference house," a model of the twin of the proposed home, built to the amended 2003 International Energy Conservation Code International Energy Conservation Code. This reference house includes the bare minimum of energy efficiency measurements and is assigned a HERS score of 100.
More efficient homes that consume less energy score lower on the scale. A home that has no net energy consumption (through use of renewable energy sources such as solar power) would score a 0 on the HERS index.
According to a report from Populus, a sustainable design company in Boulder, Colo., a 2,499-square-foot home built to the 2009 International Energy Conservation Code would score an 86 on the HERS index. Populus was able to reduce the home's HERS score to 70 as required by the county by increasing the efficiency of the furnace and the hot water tank from federal minimum standards and reducing the amount of outside air that leaks into a building.
How difficult is HERS?
Tim Carter of Idaho Mountain Builders said his company was able to build a slightly larger home, 3,000 square feet, in a way that would have complied with the county's proposed amendments.
"To get a HERS score of 68, we did really standard things," Carter said.
The home used an insulating concrete-form foundation, a structured insulated panel roof and R-22 net-and-fill insulation, slightly above the grade recommended by the U.S. Department of Energy for south-central Idaho.
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"These building techniques are not out of the ordinary in Blaine County," Carter said in a written public comment.
"Most builders would look at that and say, 'Oh, we already build to that standard,'" he added in a later interview.
Brian Poster, owner of Poster Construction, agreed that many builders already exceed the minimum requirements.
"We do a lot of things above code already here," Poster said.
As an example, he said the 2006 International Energy Conservation Code only requires an 80 percent-efficient furnace. Poster said it's difficult to even find a furnace of that grade, and his company always uses 92 percent efficient heaters in new construction.
"We have quality builders in this valley, and in reality, it's likely they're already building to this standard," Carter said.
Under the new codes, homes larger than 2,500 square feet would have to comply with a sliding scale based on square footage. The larger the home, the lower the required HERS score and the more energy-efficient the home is required to be.
County commissioners said last week that they were not sure it would be possible for a home larger than 20,000 square feet to receive the 10 HERS score required by the latest proposal, but Carter said it is achievable.
"It's not impossible at all," he said. "It's absolutely possible, but it is a high standard."
Additions of more than 301 square feet to existing homes would also come under the county's amendments. Homeowners wanting to add on would have to reduce the home's HERS score to 100 or by 30 points, whichever is more attainable. Homeowners can also install certain energy-efficient insulation and seal both the duct system and the building envelope.
None of these requirements is onerous, Carter said.
"When a house has a high HERS score, over 130, it usually has a big flaw that's easier to fix," he said.
As an example, he pointed to a log home in Warm Springs that was added to in 2000 by Idaho Mountain Builders. The home's original HERS score was 152, requiring a 30-point reduction under county code.
The main flaw in that case was the boiler, Carter said, which was performing at less than 80 percent efficiency. Replacing the inefficient unit with two 93 percent-efficient boilers reduced the home's HERS score by 55 points.
Homes in need of less drastic reductions can likely get to a compliant score by caulking and sealing around leaky windows and doors as well as open joints, Carter said, at an estimated cost of less than $2,000. Upgrading insulation and windows can also achieve a score reduction.
Fear of the future
Builder opposition to the new codes seems to stem from a profound uncertainty as to the impact these amendments would have on the industry. Despite his consistently building above International Energy Conservation Code standards and his support of the county's amendments, Poster said he didn't know what his homes would score on the HERS scale.
"I'd be happy to have our homes HERS rated," he said, "[But] it's all new to us."
Carter said he believes most opposition to the code is rooted in the construction industry's current economic turmoil.
"It's a tough climate for builders," he said. "This is an unknown quantity for some of them."
However, Poster said he fully supports the amendments because he believed they would be beneficial for the local industry.
"It would bring us to a higher standard," he said. "We build some amazing things in Blaine County. At the end of the day, it's going to be a better product for the customer."
Katherine Wutz: kwutz@mtexpress.com
Rick Stark, project superintendent for Englemann Inc., reviews the plans for a new 13,600-square-foot home being built at Prospector Knowles in Sun Valley across from Dollar Mountain in August. Under the county’s amendments to the 2009 International Energy Conservation Code, a new building of this size for the 2011 building season would need to be much more energy efficient. Photo by Mountain Express
