You’re out of free articles.
Log in
To continue reading, log in to your account.
Create a Free Account
To unlock more free articles, please create a free account.
Sign In or Create an Account.
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Welcome to Heatmap
Thank you for registering with Heatmap. Climate change is one of the greatest challenges of our lives, a force reshaping our economy, our politics, and our culture. We hope to be your trusted, friendly, and insightful guide to that transformation. Please enjoy your free articles. You can check your profile here .
subscribe to get Unlimited access
Offer for a Heatmap News Unlimited Access subscription; please note that your subscription will renew automatically unless you cancel prior to renewal. Cancellation takes effect at the end of your current billing period. We will let you know in advance of any price changes. Taxes may apply. Offer terms are subject to change.
Subscribe to get unlimited Access
Hey, you are out of free articles but you are only a few clicks away from full access. Subscribe below and take advantage of our introductory offer.
subscribe to get Unlimited access
Offer for a Heatmap News Unlimited Access subscription; please note that your subscription will renew automatically unless you cancel prior to renewal. Cancellation takes effect at the end of your current billing period. We will let you know in advance of any price changes. Taxes may apply. Offer terms are subject to change.
Create Your Account
Please Enter Your Password
Forgot your password?
Please enter the email address you use for your account so we can send you a link to reset your password:
Everything you need to know — including one big (potential) drawback.
The humble water heater, like your fridge or septic tank, is the type of home technology that you only notice if and when it breaks. For most homeowners, that’s every 13 years. But if you’re on a mission to decarbonize your life, you might want to rethink your current set-up, and perhaps consider a makeover. Per the Department of Energy, water heating accounts for roughly 18% of the average household’s energy use, making it the second largest energy expense in any home.
Back in April, the DOE released new residential water heater standards that it says will save American households approximately $7.6 billion per year on their energy bills “while significantly cutting energy waste and harmful carbon pollution.” The standards will also, in effect, phase out electric resistance water heaters, which currently account for half the U.S. market, in favor of more energy-efficient heat pump water heaters by 2029. If any of that confuses you, read on. We’re breaking down everything you need to know about this oft-forgotten, basement-dwelling home technology, from the taxonomy of water heater types to tax credit and rebate tips to product recommendations.
Andy Meyer is a senior program manager at Efficiency Maine, an independent agency that implements energy efficiency programs in the state. His team is responsible for providing resources on heat pump water heaters to Maine residents, who buy one out of every 10 purchased in the U.S.
Ben Foster is vice president of operations at Barnett Plumbing & Water Heaters, a leading heat pump water heater contractor in California. He’s also developed loaner water heater programs supported by TECH Clean California, and notes that most contractors don’t have access to loaner programs:
Joseph Wachunas is a senior project manager at the New Buildings Institute, a nonprofit working to reduce emissions and deliver climate solutions through the built environment. At NBI, he heads up the Advanced Water Heating Initiative, which aims to decarbonize water heating through heat pump water heaters.
“Heat pump water heaters are simple to install — any plumber or handy person can do it — but plumbers may not be familiar with them. So if you talk with a plumber who has concerns, consider calling another plumber,” Meyer told me. “Again, Mainers have installed over 70,000 in the last 12 years. They are no longer new.”
A heat pump water heater is made up of a compressor, storage tank, condenser, evaporator coil, fan, backup heating elements, and refrigerant. The compressor, located in the upper compartment of the water heater, uses refrigerant to heat the water in the storage tank (via the condenser, which acts as a heat exchanger). The evaporator coil and fan work to change refrigerant from liquid back to gas after the water has been heated. The backup electric heating elements kick in only in periods of high demand to ensure consistent hot water supply.
A common misconception about heat pumps in general is that they don’t work in colder climates. This is not at all the case — half of electric water heaters in Maine, for instance, are now heat pumps. As long as they are installed indoors and in an area where pipes won’t freeze (typically, a basement), heat pump water heaters work throughout the year in all climates, according to Meyer and Wachunas. The rule of thumb, per the DOE, is to install your heat pump water heater in locations that remain in the 40 degree to 90 degree Fahrenheit range year-round.
Per the DOE, replacing your standard electric water heater with a heat pump water heater can save you up to 10% on your electricity bill, reducing your water heating energy consumption and costs by up to 70%.
The number one mistake homeowners make when it comes to their water heaters is waiting until they’re broken to replace them. This severely limits your options for new water heaters — as Foster notes, no one “wants to go days without hot water, let alone weeks,” and it can take weeks or even months to fit your home for a heat pump water heater. (We’ll get into why a bit later.)
“A lot of contractors, if you want a heat pump and you have a leaking water heater that needs to be replaced today, they're just going to convince you to go with gas,” Foster said.
Some contractors have loaner water heater programs, so you can temporarily use a gas heater in an emergency situation, but these programs are few and far between. If you’ve had your water heater for 10 years or more — even if it’s working just fine — it might be time to think about replacing it. If you do, you’ll need to consider a few things about your home and lifestyle, especially if you’re considering a heat pump water heater:
Heat pump water heaters require a significant amount of space. Per Pacific Northwest National Laboratory, heat pump water heaters can require more than 6 feet of height clearance to account for their air filters, as well as a 3-foot diameter space to provide clearance for the drain pan and other connections. Additionally, the heat pump water heater should be positioned so the exhaust outlet is at least 8 inches away from a wall, door, or ceiling.
Also, since heat pump water heaters work by drawing heat from the surrounding air, they require 700 cubic feet of unenclosed space surrounding the water heater location. While it is possible to install a heat pump water heater in a location with insufficient air volume (for instance, by installing the water heater with a door equipped with top and bottom grills), this would require extra work from your contractor. Taking all these measurements into account, this basically means that a heat pump water heater requires a 10-foot by 9-foot room with an 8-foot-tall ceiling.
Heat pump water heaters also require monthly and yearly service, Meyer told me. You should change the water filter every two to six months, and clear the condensate lines to ensure your unit doesn’t get clogged with mold or bacteria. Additionally, if your unit is a hybrid, you’ll have to keep an eye on its anode rod, which can become corroded over time and lead to heating issues. You’ll have to flush your heat pump water heater annually to avoid corrosion.
If you’re going to DIY it, understanding your household’s water needs is key to sizing and installing a new heat pump water heater. First, determine your house’s peak hour demand (the maximum amount of water your house uses in one hour per day) using this worksheet from the DOE. You can then use that number (measured in gallons) to determine what size heat water heater to buy — look at the heater’s first hour rating, a.k.a. the amount of hot water the heater can supply per hour, starting with a tank full of hot water. You’ll want your heater’s first hour rating to be equal to (or ideally, higher than) your peak hour demand.
Though you should use the worksheet to determine your unique peak hour demand, a general rule is that households of one to two people should use a 50-gallon water heater, while households of three or more people should use a 65- to 80-gallon tank. The average family uses 50 gallons of hot water per day, Wachunas explained. “So even if you have lots of showers in the morning, your heat pump in two to four hours will heat that water back up and you have plenty of extra supply.”
If you’re between two sizes of heat pump water heaters, always upsize, Foster said. This ensures that the heat pump is the primary source of heat, as opposed to the much less efficient backup electric mechanisms. In other words, it’s far more efficient (and less expensive!) for a larger heat pump water heater to heat a few extra gallons of water using the heat pump than it is for a smaller heat pump water heater to have to use its electric elements to keep up with excess demand.
Since many heat pump water heaters have certain voltage requirements, you may have to upgrade your electrical panel for 240-volt hardwired service. The cost and time involved in having your service upgraded can vary and depends on whether the power lines coming into your house are above ground. If they’re underground, Foster explained, a contractor will have to excavate and run new cables, which can take over a year. The best way to determine if you’ll need to upgrade your service is to have a trusted contractor do an assessment on your home. (This is also why it’s essential to plan in advance.)
Basements are always the best places for heat pump water heaters, regardless of climate. Other common locations for installation include garages, interior rooms, and rooms outside the thermal envelope, like attached sheds and utility rooms. The garage does not have to be insulated if outdoor temperatures are usually above 50°F, but if temperatures dip below freezing and the garage is uninsulated, it’d be best to consider another location. Interior rooms, like laundry or IT rooms, are a great choice because a heat pump water heater can utilize any waste heat generated by the equipment in the room. Finally, rooms outside the thermal envelope, like attached sheds, can be even more efficient than interior spaces in hot or warm climates because of the excess hot air.
Feeling ready to go shopping? Here’s everything you need to know about the buying and installation process.
This plug-in model caused quite a stir when it came out two years ago, and for good reason. Its low voltage allows it to be plugged into a standard outlet, making it a great fit for smaller homes with fewer residents, or anyone in need of a quick fix. (This is also a relatively foolproof choice for DIYers because of the quick and easy installation process.) For those wanting a model with a bit more flexibility but still an easy install, there’s the A.O. Smith Signature 900Plug-in Hybrid, which is more expensive but has the added benefit of back-up electric resistance elements that help with higher hot water demand. Alternatively, you can go for the 120-Volt Rheem ProTerra Plug-in Water Heater with HydroBoost, which utilizes a mixing valve for maximum hot water output.
If app functionality is especially important to you, Rheem’s ProTerra line might be particularly appealing. The EcoNet app allows users to monitor the hot water heater from their phone, with status updates on potential leaks as well as compressor health, hot water availability and the unit’s set water temperature.
Another solid choice for larger families, for roughly the same price, is A.O. Smith’s Signature 900 80-Gal.For further durability, consider Bradford White’s Aerotherm Series water heaters, which can only be purchased through a qualified contractor, but are frequently praised for their resilience and anti-microbial technology.
Split-system heat pump water heaters are the answer for truly huge houses, where the heat pump itself is outside while the storage tank remains inside. “You can chain together as many heat pump units as you want with as many storage tanks as you want,” Foster said. “So you can create as big a system as you want.” While split-system heat pump water heaters are much less widely-available in the U.S. than they are in Asia and Europe, you can purchase this one online. SANCO is also shipping a new fifth generation unit soon, Quit Carbon advises, which may prove more cost-effective and will qualify for more rebates in California.
The quietest HPWH on the market, at 45 decibels, is made by A.O. Smith, according to Foster. It’s available in 50, 65, and 80 gallon sizes, so it can accommodate a variety of household types. Another quiet option is LG’s Inverter Heat Pump Water Heater, though LG is much newer to the heat pump water heater game than Rheem and A.O. Smith, so it may be more difficult to find qualified contractors.
Three more expert contractors I spoke with — Nate Adams, a longtime HVAC insulation and sealing contractor in West Virginia who specializes in electrification retrofits for homeowners; John Semmelhack, an HVAC consultant and the owner of Think Little, a building science consulting firm specializing in mechanical system design for passive house and net-zero energy homes; and Tim Portman, the owner of Portman Mechanical, specializing in electrification, heating and cooling, and home performance — had concerns about heat pump water heater installations.
Adams said heaters he’s installed have had a 50% failure rate, while Portman and Semmelhack cite a 60% failure rate. These issues have seemingly cropped up after 2018 and are almost entirely occurring with A.O. Smith and Rheem’s fifth generation of water heater models; older generations performed and continue to perform much better. “All my installs from 2014-2018 are still running to my knowledge,” says Adams. “Which is a big part of my frustration— we had this figured out already.”
The specific causes of these failures vary, spanning from tanks bursting to heat pumps losing charge, according to Adams. Semmelhack and Portman, meanwhile, pointed mainly to refrigerant leaks and compressor issues. (A.O. Smith and Rheem did not respond to requests for comment.) “All of the failures are happening inside the first year of operation,” noted Semmelhack. “So it's happening pretty quick, which makes us think that it's a factory problem and not an environmental problem inside the household.”
Semmelhack and Portman are hopeful about Cala’s new heat pump water heaters, which use an AI-powered control system to forecast hot water demand and heat the water in the tank accordingly with a heat pump. They’re aiming to start shipping those units in 2025, and you can preorder and learn more here.
Log in
To continue reading, log in to your account.
Create a Free Account
To unlock more free articles, please create a free account.
Add it to the evidence that China’s greenhouse gas emissions may be peaking, if they haven’t already.
Exactly where China is in its energy transition remains somewhat fuzzy. Has the world’s largest emitter of greenhouse gases already hit peak emissions? Will it in 2025? That remains to be seen. But its import data for this year suggests an economy that’s in a rapid transition.
According to government trade data, in the first fourth months of this year, China imported $12.1 billion of coal, $100.4 billion of crude oil, and $18 billion of natural gas. In terms of value, that’s a 27% year over year decline in coal, a 8.5% decline in oil, and a 15.7% decline in natural gas. In terms of volume, it was a 5.3% decline, a slight 0.5% increase, and a 9.2% decline, respectively.
“Fossil fuel demand still trends down,” Lauri Myllyvirta, the co-founder of the Centre for Research on Energy and Clean Air, wrote on X in response to the news.
Morgan Stanley analysts predicted Friday in a note to clients that this “weak downstream demand” for coal in China would “continue to hinder coal import volume.”
Another piece of China’s emissions and coal usage puzzle came from Indonesia, which is a major coal exporter. Citing data from trade data service Kpler, Reuters reported Friday that Indonesia’s thermal coal exports “have dropped to their lowest in three years” thanks to “weak demand in China and India,” the world’s two biggest coal importers. Indonesia’s thermal coal exports dropped 12% annually to 150 million tons in the first third of the year, Reuters reported.
China’s official goal is to hit peak emissions by 2030 and reach “carbon neutrality” by 2060. The country’s electricity grid is largely fueled by coal (with hydropower coming in at number two), as is its prolific production of steel and cement, which is energy and, specifically, coal-intensive. For a few years in the 2010s, more cement was poured in China than in the whole 20th century in the United States. China also accounts for about half of the world’s steel production.
At the same time, China’s electricity demand growth is being largely met by renewables, implying that China can expand its economy without its economy-wide, annual emissions going up. This is in part due to a massive deployment of renewables. In 2023, China installed enough non-carbon-emitting electricity generation to meet the total electricity demand of all of France.
China’s productive capacity has shifted in a way that’s less carbon intensive, experts on the Chinese energy system and economy have told Heatmap. The economy isshifting more toward manufacturing and away from the steel-and-cement intensive breakneck urbanization of the past few decades, thanks to a dramatically slowing homebuilding sector.
Chinese urban residential construction was using almost 300 million tons of steel per year at its peak in 2019, according to research by the Reserve Bank of Australia, about a third of the country’s total steel usage. (Steel consumption for residential construction would fall by about half by 2023.) By contrast, the whole United States economy consumes less than 100 million tons of steel per year.
To the extent the overall Chinese economy slows down due to the trade war with the United States, coal usage — and thus greenhouse gas emissions — would slow as well. Although that hasn’t happened yet — China also released export data on Friday that showed sustained growth, in spite of the tariff barriers thrown up by the Trump administration.
All of the awesome earth-moving and none of the planet- or lung-harming emissions.
Construction is a dirty business, literally and figuratively. Mud and gunk and tar come with the territory for those who erect buildings and pave roads for a living. And the industrial machines that provide the muscle for the task run on hulking diesel engines that spew carbon and soot as they work.
Heavy equipment feels like an unlikely place to use all-electric power in order to ditch fossil fuels. The sheer size and intense workload of a loader or excavator means it has enormous energy needs. Yet the era of electric construction equipment has begun, with companies such as Volvo, Komatsu, and Bobcat all now marketing electric dirt movers and diggers. One big reason why: Full-size machines create the opportunity to make construction projects quieter and cleaner — a potentially huge benefit for those that happen in dense areas around lots of people.
Volvo, for example, appeared at last week’s Advanced Clean Transportation Expo in Anaheim, California, primarily to tout its efforts to reduce emissions in the trucking industry via hydrogen-powered semis, electric trucks, and technological refinements to reduce pollution such as nitrous oxide from traditional diesel. But the Swedish brand also trotted out its clean power dirt movers.
The L120 electric loader that is now taking reservations has a lifting capacity of 6 metric tons on pure electric power, making it useful for job sites such as recycling centers and ports. To see such a beast in person — and displayed on pristine convention-center carpet as if it were this year’s Ford Mustang, no less — is an odd and humbling experience that elicits a little-boy level of glee at beholding a big machine. Its bucket, large enough to carry a basketball team, seems to exist on a scale that is too big for battery power, yet Volvo claims the L120 can match the performance of its diesel brethren.
Volvo also brought an electric excavator, the machine used for shoveling out huge bucketfuls of earth. The EC230 Electric is based on the diesel-powered machine of the same name, but with a stack of batteries adding up to 450 kilowatt-hours of capacity and 650 volts of power give the excavator seven to eight hours of runtime on clean electric power.
“Going to the 600-volt battery packs with similar power density that we’re using in [semi] trucks allowed us to take that into the larger construction equipment,” Keith Brandis, VP of policy and regulatory affairs for Volvo North America, told me. “A big breakthrough for us was making sure that the duty cycle — the vibration, the harshness, the temperature extremes — was proven. We have coolant that runs throughout that battery pack, so we precondition the temperatures for very cold starts as well as during very hot temperatures.”
Indeed, the two big boys on display in Anaheim expand Volvo’s lineup of electric construction machines up to seven. The new full-size offerings also take battery power up to a scale needed for serious projects, where it could cut the noise and pollution that emanate from a site. Volvo says its e-machines are already at work on the restoration project in New York City’s Battery Park, at the southern end of Manhattan, where the local government made quiet and clean construction equipment a priority.
Volvo is not alone in this space. Komatsu builds a slate of electric excavators in a variety of sizes leading up to the 20-ton PC210LCE, which the Japanese brand introduced in 2023.
At the smaller end, Bobcat now builds battery-powered mini-loaders and compact excavators. Caterpillar made an EV dump truck a couple of years ago, and more heavy-duty electric machines for industries like mining are on the way.
Although electric loaders and excavators have begun to match the capability of their combustion-powered cousins and have reached a battery runtime that spans a full workday, Volvo and other heavy equipment manufacturers face a few hurdles in convincing more construction companies to go electric. Just like with passenger cars, there is the matter of price. Battery-powered equipment costs more up front, so companies must be convinced that the savings they’ll reap via reduced fuel and maintenance costs will make the electric equipment less expensive in the long run.
And just like with passenger cars, incentives play an outsized role in affordability. Brandis noted that municipalities often have fixed budgets for equipment replacement, which is inconvenient when clean, electric equipment costs substantially more. “We typically rely on purchase incentives or infrastructure incentives, grants, or vouchers that are available,” he said, such as California’s HVIP voucher for zero-emission heavy equipment.
Then there is the construction version of range anxiety, simply ensuring there is enough electricity at any job site to recharge a division of electric loaders. At locations where sufficient electrical infrastructure is already in place, Volvo is helping electric buyers install switchgears, meters, and EV chargers built to talk to the big machines. “It eliminates one other problem point for the customer because we’ve already proven that the operability is there with the equipment,” Brandis told me.
The problem with construction, however, is that sometimes it takes place in remote locations far from easy connections. At ACT, Ray Gallant of Volvo construction equipment said this is the point at which the power has to come to the customer. Volvo recently acquired the battery production business of Proterra, which, among other things, would help the corporation develop battery electric storage solutions that it could deploy remotely — at a far-flung job site, say.
“When we’re in remote sites, we have to take the electrons to the electric machines,” he said.
The lawmakers from opposite parties discussed the Inflation Reduction Act and working together to pass legislation at Heatmap’s Energy Entrepreneurship 2025 event.
Will Republicans’ reconciliation bill successfully gut the Inflation Reduction Act?
A Democratic and Republican senator speaking last week at Heatmap’s Energy Entrepreneurship 2025 event predicted that it will not.
A proposal effectively killing the IRA “wouldn’t make it through the House,” Senator John Curtis of Utah, a Republican, said flatly at the event.
“If you believe that democracy does follow representation, those House members from those states are going to fight like hell to maintain those credits,” Senator John Hickenlooper, a Democrat of Colorado, agreed. He argued that 70% of the credits and benefits in Biden’s flagship climate law go to red states.
“I think you’re going to find enough Republicans push back on the value of these credits that there will be a thoughtful discussion and very careful review of each one. And as you know from the number of people that have spoken up on this, I think we’re in a good place, but that doesn’t mean they won’t be pushed and poked and prodded,” Curtis added, referencing the Republican signatories of letters sent to party leaders urging the preservation of the credits. Curtis and Hickenlooper both were optimistic about the chances of the credits surviving the budget reconciliation underway.
Consensus, not compromise, was the name of the game at Heatmap’s D.C. Climate Week event, which saw Heatmap executive editor Robinson Meyer sit down with the senators to discuss their approach to climate policy and bipartisan collaboration.
Robinson Meyer, Senator John Curtis, and Senator John Hickenlooper.Taylor Mickal Photography,
Curtis and Hickenlooper have worked together on the Co-Location Energy Act, which ensures that wind and solar projects can be developed on land already leased for other types of energy projects, and the Fix Our Forests Act, which emphasizes wildfire mitigation and forest health.
Thursday’s discussion also touched on working with the Trump administration on climate and energy policy. Curtis revealed that he spoke to all of Donald Trump’s nominees, including Chris Wright, about his work in the House on the Conservative Climate Caucus. “They all knew about it, and they all supported it,” he noted, adding that EPA administrator Lee Zeldin was a member of the Caucus when he served in the House.
“I think it's very important for me, for Coloradans, for me to have Chris Wright's cell phone number and be able to talk to him,” Hickenlooper stated, emphasizing that he’s willing to work with the Trump administration to achieve Colorado’s climate goals.
The Co-Location Energy Act was “common sense,” according to Curtis. The act was introduced back in December by himself and Congressman Mike Levin, a Democrat from California. “Two thirds of [Utah] is owned by the federal government, and if you say that’s off the table for development, that’s a huge problem,” he said.
Fix Our Forests, which passed the House in January after being introduced by Congressmen Scott Peters, a Democrat from California and Bruce Westerman, a Republican of Arizona, “is a case study in how we can get things done,” Curtis noted. The key to speaking to conservatives about climate change, he said, is avoiding divisive language, comparing the wrong approach to a coercive time-share presentation. “The salesman says to you, ‘do you love your kids?’ and you feel like you're backed into a corner,” he explained. “I think the way we approach this oftentimes puts Republicans on the defensive.”
Hickenlooper agreed, “You never persuade someone to change their mind about something that really matters by telling them why they’re wrong and why you’re right.”