An updated statewide energy code for new homes and commercial buildings in Maine takes effect July 1, adding to the state’s effort to fight climate change in a sector responsible for nearly one-third of greenhouse gas emissions.

The new rules will lead to tighter buildings that waste less energy. And while added insulation and air-sealing procedures will increase the cost of new construction, officials say they will create a net savings on utility bills and more comfortable living spaces.

An economic analysis done for the U.S. Department of Energy estimated the added cost to homeowners of higher energy-efficiency standards would be recouped in fewer than three years when compared with the previous standards, and result in a net annual savings of $722.

“This is critical,” said Paul Demers, Maine’s state building official who helps train code enforcement officers. “The adoption of this code is a component of the larger plan to make the state more efficient.”

But the requirements may catch some contractors off guard, said Carl Chretien, a Saco builder and board member of the Home Builders and Remodelers of Maine.

“If they’re not paying attention, there’s going to be a rude awakening,” Chretien said. “It’s going to take some learning, but they’ll get there.”


Chretien and others noted the state is offering training webinars next week for residential and commercial builders interested in the details. Slides from previous webinars also are available online from Efficiency Maine. Builders also can download software from the Department of Energy, called REScheck, to help calculate insulation, window and air sealing requirements.

Builders say the cost of complying with the new code is higher than government estimates, especially today. According to the Associated General Contractors of America, the cost of goods and services in construction rose by a record-setting 4.3 percent in May, and by 24.3 percent over the past 12 months.

Chretien said the added materials and labor will add roughly $4,000 to the cost of a $400,000 home. And at a time when the price of lumber and other building materials is going through the roof, any additional costs are unwelcome.

Mark Patterson, co-owner of Patco Construction in Sanford, figures the new code will add $8,000 or so to the cost of a 1,000-square-foot starter home priced in the $210,000 range, not counting land.

“We’re very concerned,” he said. “Most builders are small operations, one to four homes a year. They’re not up on these codes.”



The changes going into effect next month stem from bills passed by the Legislature in 2019. They also reflect months of work by state officials, builders and other interested parties to adopt a consistent code based on evolving technology and aligned with International Energy Conservation Code standards.

The revised Maine Uniform Building Energy Code is based on standards set in 2015. The so-called 2015 IECC replaces one dating to 2009. The new insulation and air sealing requirements, among other things, should cut energy use in a new home by up to 25 percent, according to the federal analysis.

The new code also applies to all Maine communities. Until recently, towns with 4,000 or fewer residents didn’t have to adopt or enforce energy building codes.

Notably, the code doesn’t cover most renovations. In a kitchen remodel where the exterior wall is taken down to the old, 2-by-4 studs, for instance, a builder only needs to fill the wall cavity with as much insulation as fits.

“You do the best you can,” said Chretien, who also recommended using spray foam to seal cracks and slow air leakage.

In addition, the state and the board that helped develop the new code gave communities a choice. They can instead adopt 2021 IECC – a so-called stretch code – which has even higher efficiency standards. The more stringent code is calculated to be 15 percent more efficient than the 2015 standards. Two Maine communities so far, Portland and South Portland, have decided to go with the stretch code.


“Adoption of this code puts Portland on a path to achieve its goal that all new construction should be net zero by 2030,” the city said in a recent statement, referring to buildings that use only as much overall energy as they produce from renewable resources.


Maine has been slow, and at times resistant, to adopting modern energy building code standards. In 2010, it was one of only 11 states without any residential building standards. A year later, during the first term of Gov. Paul LePage, Republican lawmakers sought to repeal the code altogether. That didn’t happen, but the 4,000-resident exemption was put into effect. So while the international building code is updated every three years, Maine hadn’t adopted a new version in roughly a decade.

But priorities changed with the election of Gov. Janet Mills in 2018, the Democrat-controlled Legislature and the sharp focus on climate change.

That shift is reflected by embracing better insulation standards.

For example: The 2009 energy code for homes specified wall insulation with an R-value – which indicates a material’s capacity to resist heat flow from one side to the other – of R-20. The 2015 code increases that to R-25. The 2021 code Portland and South Portland have adopted jacks up the thermal resistance to R-30.


Hitting those numbers requires advanced building techniques. To reach R-25 in a wall with 2-by-6 studs, for instance, a builder might install foam insulation board on the exterior. Sheets of continuous insulation across the wall increase the thermal value, but also cost more money.

Perhaps the most consequential new requirement deals with confirming the tightness of the building envelope, by measuring air flow to ensure that tiny cracks and gaps are sealed. That results in a building that isn’t drafty and is easier to heat and cool.

The 2009 code allowed air in buildings to be replaced up to seven times an hour. The 2015 code cuts hourly air changes to three times an hour, and it requires confirmation by using a blower door, a diagnostic tool that finds air leaks by lowering the indoor air pressure. A typical blower door test, done by a trained energy auditor, can cost $300 to $500.

A house that tight also requires ventilation beyond just opening a window to maintain indoor air quality while not wasting energy. That can mean some form of mechanical ventilation, including systems designed to exchange fresh air in an efficient manner.

Demers, the state building official, said the ventilation requirement often can be met with bathroom fans on timers, for instance, rather than more expensive systems such as energy recovery ventilators.

And while the new code won’t impact renovation projects, it may have some side benefits for most Mainers, who live in some of the oldest homes in the country. As overall energy standards rise, better insulation practices may trickle down to that kitchen wall that hasn’t been opened up in generations.

“In Maine, it’s not unusual to find newspaper and corn cobs in the wall. I’ve seen it,” Demers said.

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