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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.
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And it only gets worse from here.
Hot and humid weather stretching from Maine to Missouri is causing havoc for grid operators: blackouts, brownouts, emergency authorizations to exceed environmental restrictions, and high prices.
But in terms of what is on the grid and what is demanded of it, this may be the easiest summer for a long time.
That’s because demands on the grid are growing at the same time the resources powering it are changing. Between broad-based electrification, manufacturing additions, and especially data center construction, electricity load growth is forecast to grow several percent a year through at least the end of the decade. At the same time, aging plants reliant on oil, gas, and coal are being retired (although planned retirements are slowing down), while new resources, largely solar and batteries, are often stuck in long interconnection queues — and, when they do come online, offer unique challenges to grid operators when demand is high.
For the previous 20 years, load growth has been relatively steady, Abe Silverman, a research scholar at Johns Hopkins, explained to me. “What’s different is that load is trending up,” he said. “When you’re buying and making arrangements for the summer, you have to aim a bit higher.”
Nowhere is the combined and uneven development of the grid’s supply and demand more evident than in PJM Interconnection, the country’s largest electricity market, spanning from Washington, D.C. to Chicago. The grid now has to serve new load in Virginia’s “data center alley,” while aggressive public policy promoting renewables in states such as Maryland and New Jersey has made planning more complicated thanks to the different energy generation and economic profiles of wind, solar, and batteries compared to gas and coal.
PJM hit peak load on Monday of just over 161,000 megawatts, within kissing distance of its all-time record of 165,500 megawatts and far north of last year’s high demand of 152,700, with load hitting at least 158,000 megawatts on Tuesday. Forecast high load this year was around 154,000 megawatts. Earlier this spring, PJM warned that for the first time, “available generation capacity may fall short of required reserves in an extreme planning scenario that would result in an all-time PJM peak load of more than 166,000 megawatts.”
While that extreme demand has not been seen on the grid during this present heat wave, we’re still early in the year. Typically, PJM’s demand peaks in July or even August; according to the consulting firm ICF, the last June peak was in 2014, while demand last year peaked in July. On Monday, real time prices got just over $3,000 a megawatt, and reached just over $1,800 on Tuesday.
“This is a big test. A lot of capacity has retired since 2006 and the resource mix has changed some,” Connor Waldoch, head of strategy at GridStatus, told me. While exact data on the resource mix over the past 20 years isn’t available, Waldoch said that many of the fossil fuel plants on the grid — including those that help set the price of electricity — are quite old.
PJM’s operators have issued a “maximum generation alert” that will extend to Wednesday, warning generators and transmission owners to defer or cancel maintenance so that “units stay online and continue to produce energy that is needed.”
PJM also issued a load management alert, a warning that PJM may call upon some 8,000 megawatts of electricity users who have been paid in advance to reduce demand when the grid calls for it. Already, some large users of electricity in Virginia have reduced their power demand as part of the program. There are historically around one or two uses of demand response per year in each of the electricity market’s 21 zones.
“Demand response is a real hero,” Silverman said.
Elsewhere in the hot zone, thousands of customers of the New York Independent Systems Operator lost or saw reduced power on Monday, along with over 100,000 customers affected by voltage reductions. On Tuesday, NYISO issued an “energy watch” meaning that “operating reserves are expected to be lower than normal,” and asking customers to reduce their power consumption.
Further north, oil and coal made up 10% of the fuel mix in ISO New England by Monday night, according to GridStatus data. The region has greatly expanded behind-the-meter solar generation since 2010, which as of 2 p.m. Monday was generating over 21% of the region’s power. But the grid as a whole hasn’t been able to keep up, thanks to a nationally anomalous shortage of gas capacity and still-insufficient battery storage. As the sun faded, so too did New England’s renewable generation.
“You don’t see coal very often in the New England fuel mix,” Waldoch told me. In fact, there is only one remaining coal plant in New England, which can typically power around 440,000 homes — though that’s based on normal electricity usage. On days like the past few, it may power far fewer.
Moving into Tuesday, Secretary of Energy Chris Wright invoked emergency authorities to allow Duke Energy in the Carolinas to run certain of its units “at their maximum generation output levels due to ongoing extreme weather conditions and to preserve the reliability of bulk electric power system.”
The strained grid and high prices come as grid operators question how effectively their current and planned generation capacity can meet future demand. These questions have become especially pressing in PJM, which last year shelled out billions of dollars in payments to largely fossil fuel generators in what’s known as a capacity auction. That’s already translating to higher costs for consumers — in some cases as high as 20%. But even that could be nothing compared to what’s coming.
“If you take the current conditions that PJM is dealing with right now and you add tens of gigawatts of data to center demand, they would be in trouble,” Pieter Mul, an energy and infrastructure advisor at PA Consulting, told me.
Right now, Mul said, PJM can muddle through. “It is all hands on deck. Our prices are quite high. They’ve invoked some various emergency conditions.” But that’s before all those data centers are even online. “It’s a 2026, ’27, and beyond question,” Mul said.
Today, however, “it’s mostly just very hot weather.”
The state’s senior senator, Thom Tillis, has been vocal about the need to maintain clean energy tax credits.
The majority of voters in North Carolina want Congress to leave the Inflation Reduction Act well enough alone, a new poll from Data for Progress finds.
The survey, which asked North Carolina voters specifically about the clean energy and climate provisions in the bill, presented respondents with a choice between two statements: “The IRA should be repealed by Congress” and “The IRA should be kept in place by Congress.” (“Don’t know” was also an option.)
The responses from voters broke down predictably along party lines, with 71% of Democrats preferring to keep the IRA in place compared to just 31% of Republicans, with half of independent voters in favor of keeping the climate law. Overall, half of North Carolina voters surveyed wanted the IRA to stick around, compared to 37% who’d rather see it go — a significant spread for a state that, prior to the passage of the climate law, was home to little in the way of clean energy development.
But North Carolina now has a lot to lose with the potential repeal of the Inflation Reduction Act, as my colleague Emily Pontecorvo has pointed out. The IRA brought more than 17,000 jobs to the state, per Climate Power, along with $20 billion in investment spread out over 34 clean energy projects. Electric vehicle and charging manufacturers in particular have flocked to the state, with Toyota investing $13.9 billion in its Liberty EV battery manufacturing facility, which opened this past April.
North Carolina Senator Thom Tillis was one of the four co-authors of a letter sent to Majority Leader John Thune in April advocating for the preservation of the law. Together, they wrote that gutting the IRA’s tax credits “would create uncertainty, jeopardizing capital allocation, long-term project planning, and job creation in the energy sector and across our broader economy.” It seems that the majority of North Carolina voters are aligned with their senator — which is lucky for him, as he’s up for reelection in 2026.
The new Nissan Leaf is joining a whole crop of new electric cars in the $30,000 range.
Here is an odd sentence to write in the year 2025: One of the most interesting electric vehicles on the horizon is the Nissan Leaf.
The Japanese automaker last week revealed new images and specs of the redesign it had teased a few months ago. The new Leaf, which will arrive in 2026, is a small crossover that’s sleeker than, say, a Tesla Model Y, but more spacious than the previous hatchback versions of the car. Nissan promises it will have a max range above 300 miles, while industry experts expect the company to target a starting price not too far above $30,000.
The updated Leaf won’t be one of those EVs that smokes a gas-powered sports car in a drag race, not with the 214 horsepower from that debut version and certainly not with the 174 horsepower from the cheaper version that will arrive later on. Its 150-kilowatt max charging speed lags far behind the blazing fast 350-kilowatt charging capability Hyundai is building into its Ioniq electric vehicles. But because it lacks some of these refinements, the new Nissan may arrive as one of the most compelling of the “affordable” EVs that are, finally, coming to drivers.
Not bad for a car that had become an electric afterthought.
The original Nissan Leaf was a revelation merely for its existence. Never mind that it was a lumpy potato derived from the uninspired Nissan Versa — here was the first mass-market electric car, heralding the age of the EV and welcomed with plenty of “car of the year” laurels at the dawn of the 2010s. Its luster would not last, however, as the arrival of the Tesla Model S a couple of years later stole the world’s attention. The second-generation Leaf that arrived in 2017 was an aesthetic and technological leap forward from its predecessor, with a range that topped 200 miles in its most advanced form. It was, for the time, a pretty good EV. Almost immediately, it was overshadowed by the introduction of Tesla’s Model 3 and Model Y, which catapulted Elon Musk’s company into complete dominance of the global EV market.
It took nearly a decade for Nissan (which fell into corporate mismanagement and outright crisis in the meantime) to update the stale and outdated Leaf. As a result, you might think the new version of the OG EV will arrive just in time to be outshone again. Yet the peculiar nature of the evolving electric car market has created an opportunity for the Leaf to finally grow and thrive.
There was a time when the mythical affordable Tesla could have taken the brand into the entry-level car market, and perhaps below the magic starting price of $30,000. But that has turned out to be a distraction dangled in front of fanboys and investors. In reality, Musk effectively killed the idea as he instead rolled out the Cybertruck and pivoted the company toward the dream of total vehicle autonomy.
Thanks to Tesla’s refusal to act like a normal car company, the affordable EV market is still there for the taking. Some are already in the game: Hyundai’s little Kona Electric starts at $33,000, and I’ve lauded Chevrolet for building a base version of the Equinox EV that starts around $35,000. In the next year or so, an influx of EVs in the $30,000 to $35,000 range might really change the game for electric-curious buyers.
The new Leaf is suddenly a big part of that mix. No, it won’t compete on price with a comparable combustion Nissan like the Kicks crossover that starts in the low $20,000s (not without the $7,500 tax credit, which would have made the new crop of affordable EVs directly cost-competitive with entry-level gas cars). The Leaf is likely to start just above $30,000, with the price creeping higher for buyers who opt for better performance or more range (and as I’ve noted numerous times, you ought to buy all the range you can afford if an EV is going to be your main car).
Arriving next year to compete with the Leaf is the new Chevy Bolt, another revival of an early EV icon. Experts expect a similar price range there. The anticipated Kia EV3 should come to America eventually with a starting cost around $35,000. The Jeff Bezos-backed Slate electric truck shocked the world with its promise of a bare-bones EV in the $20,000s — but, by the time the average buyer adds enough amenities to make it liveable, most Slate trucks will probably top $30,000.
Elon Musk may have abdicated his role as the Leaf’s antagonist via his refusal to build an affordable car, but erstwhile ally Donald Trump is poised to assume the role. Since the Leaf is slated to be built in Japan, the EV would be subject to whatever tariffs might be in place by the time it goes on sale next year. A 25% tariff, plus the federal government’s flip to punishing EVs with penalties instead of rewarding them with incentives, would kill the car’s value proposition in the U.S. Perhaps, then, it will become the next great affordable EV — for everybody else.