Even as the electricity sector decarbonizes and appliance efficiency improves, reducing greenhouse gas emissions from buildings will still prove increasingly difficult, industry experts said last week.

A panelist on Texas research firm Pecan Street’s webinar Wednesday, Rocky Mountain Institute’s Amar Shah, said individual building emissions have fallen naturally with the electric sector’s decarbonization efforts. But even with complete grid decarbonization, 70 million-plus homes, buildings and institutions will still burn natural gas and fuel oil, he said.

Shah said direct-combustion emissions in buildings are a “stubborn statistic.” Even as appliances have gotten more efficient, he said, there are simply more of them now as more housing is built and population increases. New natural gas infrastructure is “built and designed and amortized” for 50 or 60 years, Shah said, and homeowners buy gas-burning appliances with no replacement plans for at least a decade.

Colin Rowan, Pecan Street’s communications director, said 40% of global GHG emissions come from the built environment, or human-made surroundings for human activity. He said there’s been a 5% increase in building emissions since 2010.

Rowan said the question remains whether the grid can handle millions more electric water heaters and heat pumps, especially given the unexpected residential demand that ERCOT was unable to meet during February’s winter storm.

Joshua Rhodes, research associate at the University of Texas at Austin, said electrification policy for buildings won’t be a flipped switch. It will take place over time, giving the grid time to adjust, he said.

ConSol Senior Policy Adviser Tom Paine said that although older housing is ripe for electrification retrofits, federal policy remains influenced by special interest groups. As long as that happens, he said, nationwide building electrification won’t gain a policy foothold.

“I don’t think there’s an appetite to cut into the bottom line” of fossil fuel industries, Paine said.

Shah predicted building electrification will continue to be a matter of “local action.” Some states are pushing for total electrification in all new construction by the end of the decade, Paine said.

“But you have a lot of other states,” Shah said, calling out Texas, Pennsylvania and other states that depend on the fossil fuel industry. “And they’re not going to dig into that unless there’s some incentive pushing them,” he added.

Paine also said residential buildings in cold climates are going to be particularly challenged because of heat pumps’ inefficiency in freezing weather. Many rely on backup heat sources that nearly always involve burning something, he said.

“We have a huge range that we have to deal with when it comes to building electrification,” Paine said. “There is no long-term policy in the federal government.”

He said consumer choice will likely become the catalyst for building electrification in places where no cohesive policy exists.

Rowan said building electrification isn’t as straightforward as transportation electrification, where a consumer can purchase a new car and plug it in.

“The technological questions have largely been solved. It’s now a matter of scaling them up,” ConSol Senior Technical Adviser William Allen said.

He said builders needed to be convinced to switch from traditional water heaters to tankless water heaters. A shift must now be made to electric tank models, Allen said, adding, “That’s kind of a hard sell.”

People will have to get used to heat pumps’ lower air temperatures as opposed to traditional furnaces’ “blast of hot air,” Allen said. He also said home chefs will have to relinquish the idea that cooking on gas stoves is better than on electric cooktops. But he said today’s induction electric stoves are a long cry from the tilted, smoking coil burners of yesteryear.

Paine agreed that consumers will drive the changeover, with costs being a major factor.

“When the thing is a natural economic choice, that’s when I think there’s the most opportunity,” he said.