Code-writing agencies and green building programs have recently been teaming up to write green standards for residential construction, leading pros to wonder whether these agreements will weave more green into the regulatory code. This year ushered in the third edition of the National Green Building Standard (NGBS), and for the first time, ASHRAE partnered with the NAHB and the International Code Council (ICC) in its development. These organizations are now working on the 2018 green building codes, which will be in place at the end of the decade.
The year 2020 is significant because it puts the industry just 10 years away from the 2030 Challenge of making all new buildings carbon-neutral, a goal adopted by the AIA, ASHRAE, the federal government, and many other organizations. By 2020, the challenge calls for new buildings to achieve 80 percent fossil fuel energy reduction compared to 2006 code. What will energy codes look like in 2020, and will these partnerships eventually make green building programs obsolete?
Jim Edelson, director of codes and policy at the New Buildings Institute in Portland, Oregon, says that green building programs and regulatory codes have begun to converge on how, when, and how much energy efficiency is required. “In the near term, green building programs will continue to lead the market,” he says. “However, it is likely that there will be a time in the next few decades when net zero buildings will be required by code to meet our society’s demands in the face of environmental challenges.”
“It is likely that there will be a time in the next few decades when net zero buildings will be required by code to meet our society’s demands in the face of environmental challenges.”
This collaborative process has forced the development of green building codes that municipalities can choose to adopt as law, says Maureen Guttman, vice president and executive director of the Building Codes Assistance Project with the Alliance to Save Energy in Washington, D.C. While green building represents a small portion of construction, she says, the codes are raising the floor on building performance.
As evidence of that upward tug, prior to 2009, when green building standards were first written, there had been a steady but slow increase in energy code — a couple of percentage points a year, Guttman says. “In 2009, we got a 15 percent bump in required energy efficiency, and another 15 percent bump in 2012, so two really big jumps in the past six years.”
On the flip side, regulatory codes also influence green rating systems. “The NGBS was designed to be an above-code rating system,” says Michelle Desiderio, Home Innovation Research Labs, Upper Marlboro, Maryland. “If there are any green building practices that are in the baseline code, those practices will be mandatory and not assigned points toward certification.”
Guttman suspects that the 2018 codes will look a lot like current codes because we’ve already made big leaps and states are more wary about deploying them. “Codes now require close to 40 percent energy reduction over 2006,” she says. “It would be nice to see at least a 5 percent improvement in efficiency over 2015 code.” Desiderio agrees. “States are not adopting the new codes as rapidly as they did years ago,” she says. “Only a handful of states are at 2012 code, let alone 2015.”
Pushback comes from builders who face constructability issues as energy reduction ratchets up. “They can only put in so much insulation before they have to take out wood without affecting the structure,” Desiderio says. “And if you put rigid foam outside the shell, how do you attach windows and cladding? Builders have to do a deeper dive to look at cost-benefit analysis.”
Occasionally builders run into equipment availability issues, too, she adds. A builder in a southern state needed a half-ton HVAC system for a multifamily building and could only get a three-quarter-ton unit. However, higher-efficiency equipment usually installs the same way as lower-performance units, making heating and cooling equipment a low-hanging fruit in the quest to meet or exceed regulatory codes.
“Propane-fueled furnaces and tankless hot water heaters are a good solution because they are very efficient and come in a whole spectrum of sizes well-suited to high-performance homes.”
Mechanical and environmental engineer James Lyons is a senior consultant at Davidson, Maryland–based Newport Partners, an energy consulting company specializing in housing. He says the emphasis in recent years has been on the building envelope, but as codes push further, there is more focus on the whole building, including heating and cooling.
“We have seen water heating become a bigger part of the code picture,” Lyons says. “And with today’s tighter houses, the heating load is so much less. Propane-fueled furnaces and tankless hot water heaters are a good solution because they are very efficient and come in a whole spectrum of sizes well-suited to high-performance homes.” Heating systems need to take air quality into account, too. Sealed combustion propane furnaces, power-vented propane storage water heaters, sealed combustion tankless water heaters, and direct-vent propane fireplaces help builders score points in both energy efficiency and indoor air quality.
While it’s not clear how far ICC codes will go, Lyons intends to keep an eye on California because it is pushing toward net zero energy homes. “California is a proving ground for a lot of these ideas,” he says.
Whatever the changes in store, Desiderio observes that while homes have made enormous strides in energy performance in recent years, they don’t look physically different than they did 20 or 50 years ago because green building standards don’t force builders to make drastic design changes. “That’s the great story of the codes and above-code rating systems,” she says.