Energy efficiency study finds good compliance for newly constructed homes in Montana
HELENA – A recently released study by the Northwest Energy Efficiency Alliance found approximately 75 percent of new homes in Montana meet the predicted annual energy usage of a house built to the statewide energy code, which is a marked improvement over a 2012 study.
Approximately 3,161 houses were built in Montana in 2018 when the study was conducted with funding from the U.S. Department of Energy and NEEA. To gauge energy code compliance, the study visited 125 new houses.
“Education efforts by the Montana Department of Environmental Quality, the Montana Department of Labor & Industry, the National Center for Appropriate Technology and NEEA seem to be paying off,” said Laura Rennick, DEQ’s Energy Bureau Chief. “Builders and homebuyers have come to know more about the advantages of building to meet the energy code standard.”
Staff at all the organizations have been providing regular energy code information and training to contractors, architects, building code departments, real estate professionals and home loan providers, Rennick said. But there is still education work to be done, especially in rural areas, she added.
Because the new study was focused on areas with the largest population growth, most of the new homes inspected were in the Billings and Bozeman areas. However about two-thirds of new homes in Montana are built outside building code jurisdiction areas – usually outside city limits. The Montana energy code still applies, but compliance inspections are not required.
All Montana home builders, including those working in rural areas, are required to certify their houses meet minimum energy code standards. This is ordinarily accomplished by attaching a completed energy code compliance label to the home’s main electrical panel box. Many of the rural homes inspected in the study lacked the label.
The Montana code requires testing of each home’s air leakage, or tightness, which is accomplished with a blower door test – a large fan assembly temporarily placed in an exterior doorway, which draws air out of the house. Instruments determine the air leakage rate of the house. The field study found that 75 percent of houses passed the blower door test requirements. Still, many rural new houses were not tested.
The study states non-code compliant items “represent a savings opportunity regardless of the above-code items. In this study, a significant portion of homes were found to not meet code in several key areas impacting energy use, durability, and comfort.” The study found that some of the most common non-code compliant measures were improperly installed wall insulation, heating system ducts not properly sealed, inadequate air sealing and non-insulated foundations.
A similar field study was conducted by NEEA in 2012. It found 64 percent overall compliance to code and predicted annual energy use with 83 percent compliance for houses built inside code jurisdiction areas and 52 percent compliance outside city limits.
“NEEA is committed to achieving energy savings by improving building energy codes in the Northwest,” said Bing Liu, senior manager of NEEA’s Codes and Standards program. “NEEA will continue to collaborate with the Montana group and provide resources on education and training to enhance the code’s implementation.”
Over the past 10 years, electrical inspectors with the Montana Department of Labor & Industry have delivered an energy code summary booklet and an energy code compliance label to all home construction sites outside regular building code jurisdiction areas. Those efforts will continue, DEQ’s Rennick said.
For more information on the study, visit DEQ’s Energy Code website and touch on the Spring 2019 Newsletter: http://deq.mt.gov/Energy/eec/EnergyCode