In Massachusetts, the statewide building code mandates a set of energy efficiency standards, like, for instance, your walls and windows need to hold in a certain amount of heat. A little over a decade ago, some cities and towns began clamoring for an even more climate-friendly building code to help reduce greenhouse gas emissions.

In response, the Legislature established the so-called “stretch code,” a set of greener efficiency standards that towns could opt into.

Since 2009, when the stretch code was enacted, 299 out of 351 municipalities in the state have adopted it. Fast forward to today, and several cities and towns want an even “stretchier” green code — one that would allow them to ban fossil fuel hookups in new construction projects or major renovations.

Last year, after Gov. Charlie Baker signed the landmark Climate Act of 2021 into law, the state’s Department of Energy Resources (DOER) began designing this new optional building code. It was unclear whether the final version would allow some progressive cities and towns to adopt an all-electric building code, but many environmentalists kept their fingers crossed.

In February, DOER published the long-awaited draft proposal and began soliciting public feedback. Reactions so far have been mixed; many environmentalists want the final code to give towns more flexibility to require all electric construction, while many in the development world are relieved this option was omitted.

Building codes can be a wonky subject. But if you’re concerned about climate change and want to understand a powerful tool Massachusetts has to fight it, here, in simple English, is what you need to know:

Why does the building code matter?

Buildings are one of the largest sources of greenhouse gas emissions in Massachusetts. Between oil and gas heating, hot water heaters and gas stoves, they’re responsible for about 27% of our annual emissions.

What’s more, DOER estimates that at least a quarter of all the square footage of buildings that will exist in 2050 in Massachusetts hasn’t been constructed yet.

In general, it’s much easier and cheaper to build an eco-friendly home or office building from scratch than to retrofit an existing structure, which is why environmentalists consider new construction the “low hanging fruit” of this decarbonization effort.

But under current Massachusetts law, a city or town is not permitted to mandate all electric construction or ban fossil fuel hookups. Attorney General Maura Healey made that clear in 2020, when she slapped down a Brookline ordinance that would end gas hookups in new homes.

In a letter, Healey explained that while she supported the town’s goal of climate-friendly construction, state law says residents have the right to all utility services (She shot down a second attempt by the town earlier this year.)

As it became clear that individual towns and cities couldn’t create greener building rules on their own, the Legislature decided to step in. Cue the Climate Act of 2021.

What does last year’s climate law do?

As part of a far-reaching climate bill, the Legislature included language directing the Department of Energy Resources to create another set of even greener building codes — what some took to calling the “new stretch code” or the “net zero stretch code,” but what we will continue to refer to as the “stretchier code.”

The goal was to create a legal way for cities and towns to experiment with greener construction, said state Sen. Michael Barrett, one of the bill’s authors. In an email, a spokeswoman for the AG’s office confirmed that a new stretchier code allowing cities to require all-electric construction would be legal.

The entire state, including the building sector, needs to achieve net zero emissions by 2050, Barrett said, “so we need to make sure that new construction over-delivers.”

While climate activists cheered the provision, many in the real estate and development community were not happy. The bill, one prominent real estate group warned, was vague to the point of unworkable, and might increase construction costs during a statewide housing crisis.

In the final version of the law, the department had to design a new stretchier building code that included a definition of a net zero building and net zero performance standards. It does not, to be clear, require cities and towns that adopt this new code to put an all-electric building mandate into place.

What’s in the new stretchier code?

On Feb. 8, the department published a topline summary for the new building code. It’s known officially as the “municipal opt-in specialized stretch energy code,” but we are going to keep calling it the stretchier code.

The proposed stretchier code creates different standards for different types of buildings based on something called the HERS rating, or Home Energy Rating System. HERS is a nationally recognized measurement of a home’s efficiency that’s determined by a professional auditor; the lower the rating, the more energy efficient the home is.

For reference, the average home in Massachusetts has a HERS rating of 51.

In the new stretchier code, towns are given three options for low rise residential homes and buildings:

  • For a home that’s all electric, the HERS rating must be 45 or lower.
  • For a home that has fossil fuel heating, the HERS rating must be 42 or lower. It also must have solar panels where feasible and be pre-wired to become all electric in the future.
  • Homes that are extremely energy efficient and meet the so-called “passive home” standard are automatically compliant if they’re all electric or pre-wired to be all electric in the future.

Homes in all three categories also need the necessary wiring for electric vehicle charging.

According to the Department of Energy Resources, implementing this new stretchier code will save builders, homeowners and renters a total of $21 billion in construction and heating or operating costs. What’s more, it could cut 500,000 tons of greenhouse gas emissions by 2030, and 694,000 tons by 2035.

The department wanted “to explore and understand the least-cost path to decarbonizing our buildings so that we can maintain a vibrant economy, meet our state’s needs for new and affordable housing, while also addressing our climate mandates,” said Maggie McCarey, director of the department’s energy efficiency division during a presentation about the new code last month.

The ‘net zero’ sticking point

“Net zero” has come up a few times in this discussion, and the casual definition seems clear: A building, on the whole, can’t add carbon to the atmosphere. But there’s no actual federal or international standard that Massachusetts could follow.

Think about it like this: Can a house with natural gas heating and solar panels be considered net zero?

And “fully electric” is another sticky term: Does the house need to generate all or some of its own electricity on site, or can it be fully electric and get all of its power from the grid? What if the grid isn’t fully carbon-free yet?

You see how this gets complicated.

DOER’s presentation included a slide that said net zero construction “does not necessitate onsite or offsite renewables, nor the assumption that an individual building is net-zero energy” because “a building becomes net zero energy when MA electric grid is net zero.”

If you’re confused, you’re not alone.

The department did not make anyone available for an interview to help clarify this point, but energy experts that WBUR spoke with think DOER is saying that homes that meet the standards of the new stretchier code are to be considered net zero.

Why are environmentalists concerned?

After publishing the draft proposal, DOER held five public meetings to solicit feedback. During at least one of those meetings, the comments were overwhelmingly critical and fell along three lines of argument.

First, it was evident that many hoped DOER would provide a legal avenue for cities and towns to ban new fossil fuel hookups, which it expressly did not do. One speaker called it “a slap in the face.”

State Rep. Tommy Vitolo suggested the new code require a home be all electric if it can be constructed at the same price as a gas powered one. Or that it allow gas heating only if all-electric construction isn’t feasible.

Second, many also raised questions about the definition of “net zero,” namely, that the presentation didn’t seem to include a succinct and workable one.

Ben Butterworth, senior manager of climate and energy analysis at the nonprofit Acadia Center, said he understands why many environmentalists were upset. DOER is “kind of putting their thumb on the scale to push developers toward building all electric,” but they’re “not explicitly making the requirement,” he said. And that’s not what people were hoping for.

Finally, another area of contention was whether cities and towns that adopt the stretchier code have the necessary leeway to try different things.

State Sen. Michael Barrett, one of the chief architects of the Climate Act and a strong proponent of decarbonization, told WBUR that the Legislature’s intent was to allow so-called “vanguard communities” like Brookline, Lexington and Arlington to take the lead and experiment.

Hypothetically speaking, maybe Brookline votes to ban all fossil fuel hookups in new construction right away, while Lexington attempts to phase it in more slowly or allow bigger carve outs for exceptions. And maybe Arlington allows natural gas stoves, but not home heating.

There’s nothing in the Climate Act that says municipalities must adopt all electric building requirements, he said, but it was supposed to give them that option.

“An absolutely rigid commitment to standardization violates the kind of experimentation that we need to do in this era of climate change,” he added.

Why are some developers concerned?

Anastasia Nicolaou, vice president of policy and public affairs at NAIOP Massachusetts, which represents commercial developers in the state, said she was relieved to see that the proposal did not allow towns to require all-electric construction. She was also pleased to see it didn’t provide an infinite number of pathways for towns that want to experiment, because, as she explained, developers don’t like operating in a world with that level of uncertainty.

Still, she remained concerned about the lack of details in the proposal and the timeline it sets forward. According to DOER, the rules will be finalized at the end of this year and ready for adoption next year.

Nicolaou added that while NAIOP and many developers it represents are supportive of decarbonization efforts, they’re concerned it’s all happening too quickly. It’s hard to not know what many cities and towns might adopt as their new building code a year from now, she said.

So where does this leave us?

The public has until Friday, March 18 at 5 p.m. to submit comments about the new stretchier code.

After this window closes, DOER will consider the feedback and write a comprehensive draft of the new building code. The public will once again have a chance to provide feedback, and DOER aims to publish the final code by the end of the year.

Read the full article in WBUR News here.