PITTSBURGH — In the quest to avoid catastrophic climate change, a movement is rising to put out the little fires burning in homes every day.
Each flame fed by natural gas, propane or oil in furnaces, water heaters and stoves is a small source of greenhouse gas emissions. All together, burning fossil fuels for heating and cooking in homes and businesses adds up to roughly 13% of total climate warming emissions in the U.S.
The push is on to switch to energy efficient electrical appliances powered by an increasingly cleaner grid — even in southwestern Pennsylvania, where cold winters, abundant natural gas and leaky, aging homes make the transition a challenge.
In fact, the Pittsburgh homes of researchers, policymakers and remodelers have been unofficial laboratories, where failing furnaces and home improvement projects have inspired strategies for how the transition can happen here.
A key tool in this fight is an unglamorous household appliance: the modern electric air-source heat pump, which efficiently moves heat rather than generating it.
For temperature control in buildings, heat pumps are essentially air conditioners that can heat and cool spaces through whole-house ducted systems or ductless “mini splits” for individual rooms.
In water heaters, heat pumps take heat from the surrounding air and transfer it to water in the tank. They are also effective dehumidifiers.
Heat pumps are typically three times more efficient than fossil fuel heaters, according to the International Energy Agency, based in Paris.
No more gas furnaces?
Electrification advocates are seizing the moment to promote a switch that climate scientists say is critical for curbing warming. In its pathway for the world to reach net-zero energy-related carbon emissions by 2050, the IEA said sales of new fossil fuel furnaces should end in four years.
Princeton researchers found that for the U.S. to meet its goal of net-zero emissions by 2050, the share of homes with electric heat pumps should more than double within this decade.
“Electrify everything” is also being pitched as an opportunity to address energy costs — especially the disproportionate burden that utility bills pose for low- and moderate-income households.
The pandemic exacerbated that burden: A study by researchers at Carnegie Mellon and other universities found that school and business closures and other early COVID-19 mitigation measures decreased commercial electricity use while increasing it by about 5% in the residential sector, with low-income and minority populations experiencing a larger impact.
Prices for natural gas, heating oil and propane reached decade-high levels this winter as economies began to emerge from the pandemic, pushing energy bills higher.
“This winter if you had a heat pump to heat your home across the U.S., your heating costs will go up — but $20, as opposed to $500 for fuel oil, $600 for propane, $160 for gas,” Alex Laskey, co-founder and executive chair of Rewiring America, told an audience at Carnegie Mellon’s Scott Institute for Energy Innovation in December.
“By our analysis, 104 million households would save on their monthly bills if you could replace their existing heating technology with a new heat pump,” he said. “And it’s disproportionate: low- and moderate-income households have the most to save.”
Running hot and cold
The technology needed to electrify homes can be deployed widely now — an appealing factor when so much climate tech, like carbon capture or green hydrogen, needs huge investments and technological leaps before large-scale deployment will be possible.
A recent study by researchers at the University of Texas, Carnegie Mellon and the University of Michigan found that heat pump adoption makes sense everywhere in the U.S. in existing single-family homes — if reducing greenhouse gas emissions is the only goal.
That fit shrinks to about a third of U.S. homes when other considerations are taken into account, including the cost of installing and running the systems and the health effects of conventional air pollution released by coal- and gas-fired plants powering the electric grid.
In Pittsburgh about 5% of single-family homes have heat pumps, but it would make both economic and environmental sense for nearly 25% of the city’s homes to adopt them, the researchers found.
Parth Vaishnav, an assistant professor at the University of Michigan’s School for Environment and Sustainability, said some of the inspiration for the study came as he was preparing for the inevitable failure of his 20-year-old furnace at his house in Swissvale when he worked at Carnegie Mellon. Heating, ventilation, and air conditioning technicians discouraged him from considering a heat pump as a replacement.
When he did the math for himself, he found that some of their warnings made sense — heat pumps are evolving quickly to work better in cold climates, but in the short-term it is often wise to have natural gas heat as a backup for the coldest days, for example.
He said in a region like Pittsburgh, where winters are cold and natural gas is cheap, households that rely on old electric resistance heaters, propane or heating oil have the most savings to gain and are the first priority to switch to heat pumps.
Heat pumps are also a good fit for households considering installing or replacing standard air conditioning, he said.
Summers in the region are getting increasingly hotter: Pennsylvania’s most recent climate impacts report forecasts that southwestern Pennsylvania will have between 41 and 62 days over 90°F by midcentury.
With a heat pump, “you’ve got an air conditioner, but for a couple thousand dollars extra, you now have a very efficient heater, which will actually reduce your heating costs for most of the year, except when it gets really cold,” he said. “And when it gets really cold, you can switch to a furnace.”
Manufacturers can also make air conditioners “heat pump ready” for a few hundred dollars extra, which will help homeowners take incremental steps toward electrification.
The future in phases
Some local experts agree Pittsburgh’s old and leaky housing stock requires a more nuanced approach than “electrify everything” all at once.
Lucy de Barbaro, an energy efficiency advocate, recommends installing heat pump water heaters, whose costs are quickly recovered through savings, and promotes induction cooktops, which are safer, more efficient and don’t release indoor air pollution like gas ranges.
But she rarely recommends replacing boilers or furnaces with heat pumps because the region’s aging homes lose so much of their heat through leaks and poor insulation.
She has encountered homes where the heating needs far outpaced their heat pumps’ capacity, forcing them into their least efficient operating mode. The owners ended up locked into paying as much as hundreds of dollars more in monthly electric bills.
“It is just not a good solution unless you have dramatically improved the performance of the home to begin with, if the home is old,” she said.
In most old Pittsburgh homes, air sealing and insulation should be the first investment to reduce energy demand, she said — and that can carry a considerable upfront cost.
That’s what Grant Ervin, chief resilience officer for the City of Pittsburgh, learned when he had an energy audit done on his century-old house.
“I couldn’t successfully electrify my home until I was able to address insulation, which also required me to address wiring,” he said. “There’s a domino effect.”
Still, he saved up to rewire and insulate his home and added split heat pump systems to provide cooling and supplement his existing furnace. Now he saves about $250 a month on his energy bills, he said.
His experience mirrors the city’s strategy for electrifying more homes: start with energy audits and then tailor efficiency improvements to each building. For example, the city allocated $10 million from its federal pandemic recovery funds to the Urban Redevelopment Authority to advance energy efficiency in low- to moderate-income homes.
In Pittsburgh, about 80% of greenhouse gas emissions come from buildings, according to the city’s most recent inventory in 2013.
This year, the city is discussing potential partnerships to analyze data on the city’s housing stock, its heating sources and the cost to transition them from existing fossil fuel systems to electric ones. It is exploring ways to collaborate on pilot electrification projects in both new construction and building renovations.
“We have started to identify targeted opportunities for electrification,” Ervin said. The city has also identified likely collaborators, including Duquesne Light, Carnegie Mellon and the Energy Innovation Center for workforce development training.
AJ Stones, a Penn Township-based contractor who specializes in energy efficient home remodeling, said he almost exclusively installs heat pump water heaters when he’s doing replacements.
But few other contractors buy them, which means few warehouses stock them. The HVAC industry is experiencing a retirement wave and the aging workforce isn’t apt to learn new systems, he said.
He sees opportunity in a younger generation of both contractors and homeowners.
“If we could start by just fixing these houses now at this phase, everything would be in place for the next phase to move to electrification when we’re ready,” he said. Consumers will have to prepare for the switch before their existing systems fail.
“People don’t make decisions until the water heater’s flooding their basement,” he said.
The debate on new construction
One area where experts agree electrification makes the most sense is in new buildings.
“For new construction, especially multifamily new construction, heat pumps are a no-brainer. We should require that we build those buildings to be all electric,” Vaishnav said. “You don’t have to bake natural gas into an asset that’s going to last, 50, 60 or 100 years. We don’t need to do that and we shouldn’t.”
Cities such as Ithaca and New York City already have laws phasing in full electrification or banning gas hookups in new buildings, and others are considering it.
In Pennsylvania, building codes are adopted at the state level and the state Public Utility Commission regulates utility connections. Still, the Republican-controlled Legislature is moving to ban electrification mandates. It is considering bills backed by the state’s natural gas utilities to prohibit communities from restricting natural gas hookups.
The Senate passed its version with a bipartisan, veto-proof majority in October.
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