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As heat waves get worse, these fixes will help keep your home cool and energy efficient.
July 2023 will almost certainly be declared the hottest month ever recorded, but it is unlikely to hold that record for long. Climate change is making heat waves more frequent, intense, and longer-lasting across the U.S.
Adapting to this hotter future is often discussed at the scale of a city; measured in early warning systems, green spaces, and cooling centers. But there’s also a lot that individual homeowners can do to help their communities and protect themselves.
While the vast majority of American households — some 88% — use air conditioning for relief, homeowners would be wise to consider a variety of additional, “passive” cooling techniques. These are strategies that can keep your home at a safe temperature during a heat wave if the power goes out, an increasingly likely scenario. They will also save you a bit of money on energy bills. In a sense, adapting your home to extreme heat is just another way of thinking about how to make it more energy efficient.
These retrofits also have wider benefits. Since air conditioners work by transferring heat from inside your house outdoors, these fixes can cool down your neighborhood. They’ll cut carbon emissions and air pollution by lowering demand for electricity. If widely adopted, they’ll also help prevent blackouts and could shrink the amount of renewable energy projects that need to be built to replace fossil fuels, alleviating pressure on conservation.
I spoke with Steve Easley, a building science consultant who specializes in energy efficiency, and Shawn Maurer, technical director of the Smart Energy Design Assistance Center at the University of Illinois, about how homeowners should prioritize their options when it comes to passive cooling.
“I always recommend that people do a home energy audit from a certified HERS rater,” Easley told me, referring to the Home Energy Rating System, a nationally recognized system for inspecting and calculating a home’s energy performance. The auditor will tell you how leaky your house is, and how well your roof insulation, windows, and other parts of your house are working to keep out heat, and help you figure out what to attack first. (Easley also recommends getting at least three quotes for any of these solutions, because different contractors bid this work out very differently.)
Below are five things you can do to improve your home’s resilience to heat. Depending on a number of factors — such as where you live, how your house is constructed, and the condition it's in — the mileage you can get out of each of these measures will vary. The good news is that the federal government and many state governments offer tax credits and rebates for most of these solutions. The Inflation Reduction Act created the Energy Efficient Home Improvement tax credit, which offers homeowners up to $1,200 per year to spend on energy efficiency improvements. As part of that, you can claim $150 simply for getting an energy audit.
Maurer said the very first thing he would do to improve the efficiency of a home is to seal up any cracks where air can get in — for example, along the edges of the floors, around the windows, and in the ceiling around light fixtures. “That carries in moisture, heat, and everything from outdoors into the house. It's going to offset any air conditioned air you got inside the house. So air leakage is usually the place we recommend to start,” he said. “And then from there, it's what your budget can handle as far as adding more insulation to your house.”
Insulation comes in a wide range of materials, such as fiberglass and rock wool, blown cellulose, and rigid foam boards. It can be blown into your walls, installed on the floor of the attic, or underneath your roof deck. It’s a jack-of-all-trades when it comes to energy efficiency, since it keeps heat inside in the winter and blocks it from entering in the summer. That means it’s a great option for those in colder climates that also want to prepare their homes for hotter summers.
A 2021 study by a group of researchers at Lawrence Berkeley National Lab modeled the efficacy of a wide array of passive cooling measures in low-income homes in Fresno, California. It found that roof insulation, along with solar-control window films, which we’ll get to in a moment, were the two most effective ways to keep heat from entering the buildings. However, the authors note that roof insulation is an expensive major retrofit, and recommend that it only be done when the roof needs replacement.
A good first step might be finding out what kind of insulation you already have. The most important metric when it comes to insulation is called “R-value,” and the higher the number, the more effective it is. Older homes may have attic insulation as low as R-13, whereas modern building codes typically require insulation between R-38 and R-60.
The new federal tax credit offers up to 30% of the total cost of a project for air sealing and insulation, maxing out at $1,200 total. (Labor costs are not covered by the credit.)
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Having a light-colored roof and exterior will most certainly keep your home cooler than darker options, but not all light colors are created equal. “Cool” roofs and walls are made with special materials that reflect solar energy back into space, preventing it from being absorbed by the building. They also have high “thermal emittance,” meaning they release a lot of the heat that they do absorb, rather than sending it indoors.
All kinds of materials have been developed with these properties. For roofs, there are tiles, shingles, membranes, liquid coatings, and products made of slate, wood, and metal.
Cool roofs don’t necessarily have to be white, although the color does work very well. According to a database maintained by the Cool Roof Ratings Council, the most effective products tend to be bright white coatings, but there are also gray, green, blue, brown, and tan products that are rated highly.
For reflective walls, the most effective products similarly come in white and other light-colored paints, which can reflect 60 to 90 percent of sunlight when new. An extensive 2019 study of reflective wall paints by the same group at Lawrence Berkeley National Lab found that cool walls can reduce annual energy use in single-family homes in warmer U.S. climates by 2% to 8.5%.
Easley said it’s worth considering a cool roof if you have a central air conditioning system in your attic. Otherwise, attics in places like Arizona can get upwards of 130 degrees, taxing the equipment and forcing it to work harder. If your attic isn’t home to your AC, it may only make financial sense to do this kind of retrofit if your house is already in need of a new paint job or your roof needs work.
But it’s probably not worth considering a cool roof if you live in a colder climate, like the Northeast and upper Midwest, since cool roofs can actually make it colder inside in the winter.
There’s no federal incentives for cool roofs, but several states and utilities offer rebates.
This is a big category, and it’s easy to get overwhelmed by the options. Starting with those that will likely cost the most to the least, you can:
• Replace your windows altogether.
• Add storm windows to the interior or exterior of your existing glass.
• Purchase films that can be applied to the existing glass to increase its reflectivity.
• Install external shutters or awnings that block the sun.
• Install interior blinds and curtains that block the sun.
Here’s a rundown of each option.
New windows: Replacing your windows can cost tens of thousands of dollars, so unless they are already in need of repair, you may want to hold off on that option. But when the day does come around, you’ll want to look for “Low-E” windows, which stands for low emissivity. The inside of the glass is coated with microscopic layers of silver that reflect heat while still allowing light to pass through.
Within that category, you’ll also want to look for windows that have what’s called a low “solar heat gain coefficient.” This measures how much heat is absorbed by the glass and transferred inside. It’s rated on a scale of 0 to 1. If you live somewhere that’s sunny year round like Arizona, you ideally want one rated 0.25 or lower.
Through 2032, homeowners can claim up to $600 in federal tax credits for purchasing Energy Star rated windows.
Storm windows: Rather than replacing your windows entirely, it’s far cheaper to install storm windows with Low-E glass, which basically involves bolting another window to the outside of your house. Storm windows have an added benefit of improving air sealing, eliminating drafts.
Film: An even lower-cost option is to look into films with low solar heat gain coefficients that can be applied to existing windows. However, Easeley warned that many manufacturers will void your warranty if you add films to your windows.
Shutters, awnings, blinds, and curtains: Exterior shutters and overhangs that block the sun from ever reaching your windows will generally be more effective than interior shades or blinds, but all of these measures can help. “Window blinds and curtains are really dirt cheap ways to control energy,” said Maurer. “It’s not a very good buffer, but it’s something.”
The Berkeley study on passive cooling measures notes that blinds moderately improve how much heat from the sun enters your home, but they can feel more effective by reducing the sensation of sunlight streaming into your house.
If you still have any incandescent lights, they can also be a significant source of heat. They should be replaced with LED lights.
Planting trees, climbing ivy, and other vegetation can also passively cool your house by shading both your house and any surrounding pavement. However, if you have solar panels, or plan to get them in the future, do not plant trees on the south side of your home as it may reduce the solar system’s effectiveness.
Maurer cautioned that if you do a bunch of work in your home to reduce your cooling needs, you’ll want to keep that in mind if you ever have to replace your air conditioner. He advised having a contractor come in to re-measure what size system you need, since doing a like-for-like replacement will probably be overkill and could result in it malfunctioning.
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In a press conference about the newly recast program’s first loan guarantee, Energy Secretary Chris Wright teased his project finance philosophy.
Energy Secretary Chris Wright on Thursday announced a $1.6 billion loan guarantee for American Electric Power to replace 5,000 miles of transmission lines with more advanced wires that can carry more electricity. He also hinted at his vision for how the Trump administration could recast the role of the department's Loan Programs Office in the years to come.
The LPO actually announced that it had finalized an agreement, conditionally made in January under the Biden administration, to back AEP’s plan. The loan guarantee will enable AEP to secure lower-cost financing for the project, for an eventual estimated saving to energy consumers of $275 million over the lifetime of the loan.
“These are the kind of projects where we’re going to partner with businesses to make our energy system more efficient, more reliable, ultimately lower cost,” Wright said on a call with reporters.
And yet in the past few months, the department has also canceled loan guarantees and grants for other transmission projects that were expected to provide those same benefits — including the Grain Belt Express, an 800-mile line set to bring low-cost wind power from Kansas to the Chicago metropolitan area in Illinois.
“We don’t care about authorship,” Wright told reporters, acknowledging that the AEP loan was conditionally approved by the Biden administration. “Not all of them were nonsense. The ones that are in the interest of the American taxpayers, in the interest of the American ratepayers, and there’s a helpful role for government capital — we’re happy to support those.”
When asked specifically why AEP’s proposal met his criteria while the Grain Belt Express didn’t, Wright first made an argument about cost. “I have nothing against the Grain Belt Express,” he said. “I suspect it’ll still be developed. But it’s far more expensive on a per mile basis since it’s a brand new transmission line.”
His subsequent comments, however, hinted at a more significant shift in approach. He went on to argue that the project came with an unacceptable amount of risk since the developers didn’t have buyers yet for the power coming down the line. It was trying to “close on arbitrage,” he said, by buying up cheap wind power that was stranded in Kansas and bringing it to a larger market. “It’s a more commercial enterprise,” he said. “That’s done with private entrepreneurs and private capital.”
It’s important to note that the Grain Belt Express loan guarantee would have been issued under an innovation-focused program within the Loan Programs Office that was specifically geared toward higher risk projects that banks won’t otherwise touch. The AEP project is part of a different program focused on more mature technologies, with a goal of reducing the cost of major utility infrastructure upgrades to ratepayers.
When I floated Wright’s comments by Jigar Shah, the former head of the Loan Programs Office under the Biden administration, he was flummoxed. “It’s nonsensical,” he said. To Shah, taking Wright’s risk aversion to its logical conclusion would mean, for instance, that the office should not fund any nuclear energy projects. “If this becomes a new standard, that means nuclear is dead in the United States,” he said.
AEP is the first developer to secure a loan guarantee under the Energy Dominance Financing Program, Congress’ new name a Biden-era program within LPO that offered loan guarantees to utilities to “retool, repower, repurpose, or replace energy infrastructure.” Initially called the Energy Infrastructure Reinvestment Financing Program and created by the Inflation Reduction Act, it focused on projects with climate benefits, like making efficiency upgrades to power plants or installing renewables on the site of a former coal plant.
In the Biden administration’s view, AEP’s project would “contribute to emissions reductions by supporting existing and new clean generation by expanding transmission capacity in the regions in which they operate.”
Trump’s One Big Beautiful Bill Act rebranded the program and removed any requirements that projects reduce emissions. On Thursday’s call, Wright seemed to imply that it wasn’t just the Biden-era loan program that had been renamed. “The Loan Program Office is being rechristened the Energy Dominant Financing — it is the rechristening of the same department,” he said in response to a question about the office’s remaining loan authority. The Department of Energy did not respond to my request for clarification.
None of that means that the potential emissions benefits from AEP’s project won’t materialize. Limited transmission capacity is one of the biggest obstacles for bringing new wind and solar power online, and reconductoring could also reduce line losses, making the overall grid more efficient.
The transmission project — which includes plans to rebuild some power lines and reconductor others — will ultimately increase capacity by more than 100%, a spokesperson for AEP told me. The first phase will involve upgrades to about 100 miles of wires across Ohio and Oklahoma, while future phases will tackle lines in Indiana, Michigan, and West Virginia, with the intent of meeting growing demand from data centers and manufacturing development, according to a press release.
When reporters asked Wright about the other conditional loan guarantees the Biden administration had issued under the Energy Infrastructure Reinvestment program that are still pending, the secretary stressed that he was looking for applicants that had identified a clear set of projects they would implement. “Many were done in a hurry, without really even having the projects that the loans would be associated with identified. You can end up with a grab bag of projects without a lot of say for where the money went,” he said.
Wright accused the Biden administration of failing to ask applicants to detail the impact the projects would have on taxpayers and ratepayers — a key question his colleagues are now asking.
Shah disagreed with that portrayal. The whole point of the program was to reduce interest rates for utilities and require them to pass on the benefit to ratepayers. All of the projects awarded conditional commitments met that bar, he said.
He warned that if the Trump administration didn’t honor the remaining conditional commitments to utilities under the program — all 10 of them — it risked losing the trust of any new companies it attempts to make similar deals with.
“Most of the nuclear projects that they’re looking to chase are not going to get closed until 2028. And so what signal are they sending? That projects that get approved in the last year of an administration are not going to be honored in the next administration?”
On a new loan guarantee, a Nord Stream 2 revival, and AI-aided oil recovery
Current conditions: As Tropical Storm Lorenzo looks likely to dissipate over water by Friday, AccuWeather has slashed the season’s forecast to six hurricanes from nine • Severe thunderstorms near Little Rock, Arkansas, and Memphis, Tennessee, are likely too spotty to relieve long-standing drought in the Mississippi River Basin • The Netrokona district of northeastern Bangladesh is scorching in temperatures nearing 100 degrees Fahrenheit.
A rendering of the future Cascade Advanced Energy Facility. Amazon
A year after Amazon invested in the small modular reactor developer X-energy, the tech giant has unveiled its plans to build a nearly gigawatt-sized plant in southeastern Washington, where it will install the nuclear company’s next-generation technology for the first time. The Cascade Advanced Energy Facility is set to begin construction “by the end of this decade,” with hopes of generating power from up to a dozen of X-energy’s 80-megawatt high-temperature gas-cooled reactors sometime “in the 2030s.” Amazon plans to build the plant in three phases, with four reactors at each stage, eventually reaching 960 megawatts in capacity. Located in Richland, Washington, along the Columbia River, the facility will nearly double the output of the Pacific Northwest’s only nuclear plant, the nearby Energy Northwest’s Columbia Generating Station.
In a sign of what Heatmap’s Katie Brigham called “the nuclear dealmaking boom” back in August, rival microreactor developer Oklo suggested at a recent public meeting in Tennessee that it may propose building some of its reactors near the Oak Ridge site of its debut nuclear waste recycling project, the Knoxville News Sentinel reported Monday. On Tuesday, meanwhile, the U.S. Army announced its new Janus program, which aims to supply bases by 2028 with microreactors like the ones Oklo aims to build, which generate 20 megawatts of electricity or less. The reactors would be owned and operated by private companies. “What resilience means to us is that we have power, no matter what, 24-7,” Jeff Waksman, principal deputy assistant secretary of the Army, told The Wall Street Journal.
The Department of Energy’s Loan Programs Office has largely revoked deals made under the previous administration since President Donald Trump returned to office. But on Thursday morning, the agency’s in-house lender announced a $1.6 billion loan guarantee to a subsidiary of utility giant American Electric Power to upgrade and rebuild about 5,000 miles of transmission lines across Indiana, Michigan, Ohio, Oklahoma, and West Virginia. “This loan guarantee will not only help modernize the grid and expand transmission capacity but will help position the United States to win the AI race and grow our manufacturing base,” Secretary of Energy Chris Wright said in a press release.
The move came a day after a federal judge blocked the Trump administration’s effort to fire thousands of federal workers amid the ongoing government shutdown. At a hearing Wednesday, U.S. District Judge Susan Illston, a Clinton appointee based in California, granted labor unions’ request for a temporary restraining order to halt the dismissals. The hearing took place at the same time White House budget director Russ Vought appeared on the late conservative commentator Charlie Kirk’s podcast to preview his plans to lay off as many as 10,000 federal workers as the shutdown continued. The hearing will pause the job cuts for the roughly 4,000 workers who received notice so far. Illson said during the hearing that she granted the temporary restraining order because administration officials had “taken advantage of the lapse in government spending, government functioning, to assume that all bets are off, that the laws don’t apply to them anymore, and that they can impose the structures that they like on the government situation that they don’t like,” News From The States reported. “Things are being done before they’re thought through — very much ready, fire, aim.” Nearly 200 employees at the Department of Energy began receiving notices last week, as I wrote in yesterday’s newsletter.
The underwater explosion of the Nord Stream 2 pipeline connecting Germany to Russia’s gas supply remains one of the world’s biggest geopolitical whodunnits, and Berlin’s fellow European Union members seem keen to keep it that way. In just the past two days, Poland and Italy blocked extradition requests to send suspected saboteurs to Germany for trial. But the Germans aren’t just looking to figure out who’s responsible for destroying the megaproject. The Federal Ministry for Economic Affairs and Energy is considering restarting the certification process for the pipeline, the daily newspaper Der Tagesspiegel reported Wednesday. The previous German government had ruled out a restart of the pipeline in March after news broke that Russian President Vladimir Putin’s business allies were angling to restore the project. In June, the new government under conservative Chancellor Friedrich Merz began examining legal avenues to block any future plans to reactivate the pipeline, the Financial Times reported at the time. But under current law, the economic ministry said this week a restart “cannot be ruled out in the medium term.”
Ohio passed a new law to fast-track energy projects on former coal mines and brownfields, Canary Media reported Wednesday. Called House Bill 15, the legislation took effect in August and lets the state’s Department of Development designate the former industrial sites as “priority investment areas” at the request of local governments. Roughly a third of Ohio’s 88 counties ban wind, solar, or both, but the language in the bill makes clear that “it was meant to be technology-neutral,” Rebecca Mellino, a climate and energy policy associate at The Nature Conservancy, told Canary’s Kathiann M. Kowalski.
A transition from coal could yield significant health benefits, as The New York Times reported on Tuesday. A recent study found that, when a coal-processing facility near Pittsburgh shut down, the number of emergency room visits for respiratory issues in the surrounding area dropped by about 20% in the month following the closure.
The world’s annual consumption of oil isn’t expected to peak until the mid-2030s, and by 2050 it will reach a cumulative 1 trillion barrels, according to the consultancy Wood Mackenzie’s forecast. But production that’s either already onstream or ready for development is expected to gradually decline to 650 billion barrels per year by the mid century. What will make up the difference? “Traditional exploration will play its part but can’t get anywhere near bridging a gap of this scale,” Wood Mackenzie analysts wrote in a blog post on Wednesday. “Even the 21st century’s biggest new play, Guyana, with 15 billion barrels of oil, barely makes a dent.” To identify potential new resources, Wood Mackenzie rolled out a new AI-powered benchmark called Analogues, which “uses a machine learning method known as clustering to identify each field’s closest matches across 60 different attributes spanning rock properties, fluid characteristics, and commercial factors.” The AI tool could increase the share of recoverable conventional oil reserves by nearly 42%.
A chart showing how the AI "analogues" could bolster oil drilling. Wood Mackenzie
Fusion energy is rapidly accelerating in the U.S., and the Department of Energy is poised to release a national plan for speeding up the deployment of the technology. In the meantime, states can prepare by beefing up regulatory capacity, speeding up permitting, clearing interconnection queues, and creating special tax credits. That’s according to a new roadmap from the Clean Air Task Force. “As fusion energy moves closer to commercial reality, states have a window of opportunity to prepare,” Jack Moore, a fusion policy consultant at CATF, wrote in a blog post. “Proactive policy design today can help states position themselves to create an effective environment for fusion energy deployment tomorrow.”
Editor’s note: This story has been updated accurately reflect oil demand by 2050.
This thing is a certified clunker.
Americans certainly got the message about the end of the EV tax credit. With the $7,500 benefit set to disappear at the end of September, electric vehicle sales surged to record numbers in the third quarter of 2025 as buyers raced to beat the deadline.
The rising tide lifted just about all EVs — but not the struggling Tesla Cybertruck. According to new numbers from Kelley Blue Book, Tesla sold just 5,385 Cybertrucks from July to September, less than half as many as it delivered during the same period in 2024. The company is now expected to sell around 20,000 of the metal EVs this calendar year. That’s down from around 50,000 last year, and less than 10% of the 250,000 total Elon Musk once predicted as the truck’s annual sales figure.
Cybertruck was well on its way to flop status before these sales numbers. With its purposefully jarring aesthetic, the EV for edgelords was never going to be as popular as Musk proclaimed, and that was before his relationship to Donald Trump and online provocations pushed many more people away from the Tesla brand. Cost didn’t help, either. Tesla once said it would sell a $40,000 basic version of Cybertruck, a price point that might have enticed some buyers beyond the Musk fanboys who became early adopters, but the cheapest one you can actually buy today is around $60,000.
Still, the vehicle’s third-quarter performance is particularly damning in comparison to nationwide EV sales, where the tax credit’s demise ignited a fire sale. Americans bought more than 430,000 EVs during the quarter, an increase of about 40% from the second quarter of 2025 and about 30% from the third quarter of last year. Popular vehicles including the Chevy Equinox EV, Hyundai Ioniq 5, Ford Mustang Mach-E, and Honda Prologue surged to sales of more than 20,000 during the quarter. Electric trucks including the Rivian R1T, Ford F-150 Lightning, and GMC Hummer EV saw sales increases despite having high prices that rival the Cybertruck’s.
Tesla itself, despite months of bad press, did well, too. The brand’s share of the overall EV market continues to wane, reaching a new low of 41%. But the surge temporarily stabilized its tumbling sales, with plenty of people snatching up Model 3s and Model Ys while the getting was good. Those two vehicles remained the two best-selling EVs in America, with Tesla selling more than 114,000 Model Ys and more than 53,000 Model 3s.
Yet the good times did nothing to spur driver interest in Cybertruck. In fact, public enthusiasm for the vehicle might be even lower than it seems, because it turns out that one of the top customers for Musk’s electric tank is Musk himself. Electrek reports that his other companies, such as SpaceX and xAI, have been accumulating Cybertrucks as their company cars. Tesla is replacing some of its own fleet with Cybertrucks, as well.
The move makes sense for Musk. Because of weak overall demand, Cybertrucks are sitting idle on lots; selling them to his businesses at least puts them to work. The scheme also might improve the appearance of Tesla’s sales numbers, Electrek speculates. By locking in some of these sales with a downpayment before the end of September, Tesla can deliver Cybertrucks to Musk’s other business in the weeks to come and still get the tax credit on them. The approach could boost sales numbers for a fourth quarter that’s likely to be difficult with the disappearance of the federal incentive.
Now that Cybertruck has become Elon’s Edsel, Tesla’s hopes for an EV sales revival lie largely with the new “Standard” versions of its two best-sellers. These trim levels strip away some of the amenities from the Models 3 and Y to bring their starting prices down to $37,000 and $40,000, respectively. It’s far from clear that this will succeed. Anyone shopping for an EV solely on price could wait for the upcoming new versions of the Nissan Leaf and Chevy Bolt, which are expected to come in at $30,000 or less. The Equinox’s $35,000 starting price, five-grand less than even the budget Model Y crossover, has spurred its recent success.
Still, with 320-plus miles of estimated range and at least some of Tesla’s best features, the budget versions could be compelling cars at those prices. At the very least, they’ll speak to more drivers than the Cybertruck does.