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Originally published on RMI.org.
By John Matson

As the world warms and the demand for cooling increases, many homes will require an “all of the above” approach to keep cool without further contributing to global warming. That can include high-performance cooling systems that use climate-friendly coolants and consume relatively little energy, as well as building design approaches that offset the need for mechanical cooling in the first place.

In this post, we look at some passive cooling strategies that help keep an innovative tiny house comfortable during California summers, without the use of a mechanical cooling system.

Brett Webster, a manager in RMI’s Carbon-Free Buildings program, lives in a 170-square-foot home in Sonoma County, California. Brett and his partner helped design and build the solar-powered tiny house as part of a graduate project, and they have lived in the demonstration home for about five years. The home itself was built on a 24-foot-long trailer and can be hitched up to a truck for relocation. So even though Brett and his partner have lived in their tiny home for years, they have moved twice in that time between Northern California locations (and their respective microclimates).

Strategic Shading

The walls of the tiny house are clad in reclaimed cedar slats over one-inch-thick panels of cork, which provides a layer of continuous insulation, reducing the thermal bridging of the wooden wall framing. Because the carbon sequestered in cork trees can exceed the carbon emissions of producing cork products, cork is often considered a carbon-negative material. The cedar siding is separated from the cork by an air gap, which allows the wooden slats to shade the cork and absorb solar radiation, while slowing the rate of heat transfer directly to the house. The walls of the structure are insulated with recycled denim to further limit heat gain in warm weather and heat loss in cool weather.

Pulley-mounted shade awnings, made from cedar slats to match the siding, cover the largest expanse of glass on the tiny house: a sliding-glass door at the entry to the home. Webster says that the shade structure extends far enough to block solar radiation from pouring through the glass entryway in summer, but it can let in sunlight and heat in winter, when the sun is lower in the sky.

The ability to shade the windows in summer and admit sunlight during the winter is critical to maintaining passive comfort in the house. The windows that the design team chose for the tiny house are well-insulated (low U-value) but are also designed to let the sun’s heat in (high solar heat gain coefficient), because the Bay Area is mostly a heating-dominant climate zone. During the summer, when that heat gain is not desirable, shading the windows is a necessity.

Ceiling and Roof

A layer of BioPCM phase change material in the ceiling acts like thermal mass to absorb and store heat that would otherwise warm the interior space. Adobe buildings and concrete-walled structures similarly benefit from thermal mass that prevents the interior from becoming overheated during the day. But phase change material is lightweight, making it more appropriate for applications like the ceiling of a tiny house, and it doesn’t have the carbon footprint of concrete. (Cement production alone accounts for about 8 percent of global carbon emissions.)

The phase change material, which comes embedded in sheets that can be rolled out between ceiling joists like high-tech bubble wrap, melts from solid to liquid at 77 degrees F (25°C). As it changes phases, the material absorbs a lot of thermal energy, preventing the temperature from exceeding 77 degrees until its heat-absorbing capacity has been reached, like a sponge that can’t soak up any more water.

The tiny house’s roof is designed to harness much of the sun’s energy and reject the rest. A 2.3-kilowatt solar array shades much of the tiny house’s roof and feeds into a Tesla Powerwall to store electricity for nighttime use. The “cool roof” is also covered with a light-colored acrylic roofing membrane to minimize heat gain from solar radiation.

Some Energy Required (But Not Much)

In addition to the passive cooling approaches described above, the tiny house relies on a few efficient electric devices to provide airflow and ventilation. Even though they don’t qualify as strictly “passive” technologies, ceiling fans and other efficient electric devices have long gone hand-in-hand with passive cooling approaches. The ventilation and airflow systems in the tiny house consume very little energy and allow the building to remain comfortable without a dedicated mechanical cooling system.

A high-efficiency overhead ceiling fan consumes 4–18 watts of electricity and ensures occupant comfort in warmer temperatures. “Airflow creates a cooling sensation that’s extremely effective,” Webster says. According to the US Department of Energy, using a ceiling fan can significantly offset the need for air conditioning, allowing occupants to raise the thermostat by about 4 degrees F without sacrificing comfort.

The well-insulated structure is designed to be closed off to the outside during hot days in the summer, so the windows do not provide any natural ventilation during the daytime. The tiny house therefore relies on an energy recovery ventilator to bring fresh air into the house. An energy recovery ventilator uses a heat exchanger to reduce the thermal energy of the outside air before it enters the house, thereby providing ventilation without flushing warm air into the building. In the winter, it does the reverse, using the heat of the outgoing stale air to warm the incoming fresh air.

Unplugging

The tiny house’s passive design and minimal energy requirements for ventilation make it fully capable of going off-grid, especially in the summer months when solar energy is abundant. And even if most of us aren’t ready to commit to living in a 170-square-foot house on wheels, the lessons from Webster’s tiny house and other passive homes provide a powerful reminder: Even for energy-intensive applications like cooling, with thoughtful design, you can do a lot with a little.

Image gallery courtesy of RMI.


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Genesis GV90 spotted in the US, offering a sneak peek at its ultra-luxe interior

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Genesis GV90 spotted in the US, offering a sneak peek at its ultra-luxe interior

The GV90 is set to raise the bar as the most luxurious Genesis SUV. If you thought the GV80 was impressive, wait until you see this larger, three-row electric flagship. After it was recently spotted in the US, we are getting our first glimpse of the ultra-luxe Genesis GV90’s interior.

First look at the Genesis GV90 interior in the US

Genesis previewed the flagship SUV at the NY Auto Show last March with the Neolun concept, which the brand refers to as its “ultra-luxe vision of luxury SUVs.”

It’s not only stunning on the outside, but the full-size SUV will introduce advanced new tech and upscale design features for “a whole new level of luxury.”

Drawing inspiration from Korean aesthetics, the interior is fit for royalty. The concept featured a “Royal Indigo” cashmere and a vintage-like “Purple Silk” leather. Genesis topped it off with dark-colored wood accents for an even more luxurious feel.

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After it was spotted in public in California, it looks like the interior of the Genesis GV90 will retain some elements from the concept.

The new photos, courtesy of The Korean Car Blog, offer a sneak peek at what we can expect when it arrives in production form.

You’ll notice that the color scheme remains largely the same, with purple accents on the door trim, seats, and other interior elements.

The GV90 will serve as the luxury brand’s tech beacon, featuring Hyundai Motor’s latest technology and software. A 24″ infotainment system will sit at the center with navigation and voice command recognition.

It will also feature a 3D audio experience with tweeters, midrange speakers, woofers, and subwoofers strategically placed, creating an immersive audio experience. The iconic Crystal Sphere is not only a centerpiece, but it will also serve as a hi-fi tweeter speaker.

According to Luc Donckerwolke, Genesis’ chief creative officer, the concept is “the epitome of timeless design and sophisticated craftsmanship.” Do you agree?

With GV90 models now in public testing, Genesis appears to be on track to launch the flagship SUV in mid-2026. Earlier this month, we got a closer look at the exterior after it was caught testing at the Nürburgring with less camo.

More details, including prices and final specs, will be revealed closer to launch. However, it is expected to ride on Hyundai’s new eM platform, which will replace its current E-GMP.

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SEC drops Binance lawsuit, ending one of last remaining crypto enforcement actions

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SEC drops Binance lawsuit, ending one of last remaining crypto enforcement actions

Jakub Porzycki | Nurphoto | Getty Images

The SEC has formally dropped its lawsuit against Binance and founder Changpeng Zhao, bringing an end to one of the last remaining crypto enforcement actions brought by the agency.

In a Thursday filing in the U.S. District Court for the District of Columbia, lawyers for the SEC and Binance jointly moved to dismiss the case, which was first brought in June 2023.

The original complaint accused the crypto exchange of violations including illegally serving U.S. users, inflating trading volumes, and commingling customer funds. The agency also claimed that Binance unlawfully enabled trading in crypto assets it viewed as unregistered securities, an argument that was also used against Coinbase, Kraken, and others under prior SEC leadership.

The dismissal marks a symbolic end to one of the most aggressive crypto crackdowns in U.S. history, and comes as the Trump administration makes a concerted effort to prove that it’s an ally to the industry. The Justice Department has already shut down its crypto enforcement team, and the Commodity Futures Trading Commission is now set to be led by a venture capitalist with close ties to crypto.

Binance is the largest digital assets exchange in the world by volume. It recently forged ties with World Liberty Financial, a project that aspires to be a crypto bank and funnels 75% of profits to entities linked to the Trump family. Binance is taking a $2 billion investment from the Emirati state fund MGX entirely in USD1, a stablecoin newly launched by the World Liberty team.

Binance and World Liberty are also deepening their footprint in Pakistan, where WLF co-founder Zack Witkoff, the son of U.S. Middle East envoy Steve Witkoff, recently struck a deal with the government. Around the same time, Zhao was appointed as an adviser to Pakistan’s newly formed Crypto Council, a state-backed body tasked with shaping national digital asset policy.

Binance CEO Richard Teng discusses U.S. crypto adoption at the Digital Asset Summit

The SEC was the last major regulator still pursuing Binance after a $4.3 billion settlement with the U.S. government last year that saw Zhao plead guilty and step down as CEO, while avoiding jail time and retaining much of his wealth.

The agency’s motion to dismiss was granted with prejudice, meaning the SEC can’t refile the same claims.

Under the SEC’s new leadership, the agency has shifted away from enforcement and toward engagement and regulatory rollback. It’s held a series of roundtables led by Commissioner Hester Peirce and newly appointed Chair Paul Atkins.

The SEC has also begun dismantling key rules that once kept Wall Street on the sidelines. In January, it scrapped Staff Accounting Bulletin 121 — a controversial directive issued under former Chair Gary Gensler that forced banks to count crypto holdings as liabilities on their balance sheets. Peirce celebrated the reversal on X, posting, “Bye, bye SAB 121! It’s not been fun.”

In February, the agency followed up with new guidance indicating that it doesn’t view most meme coins as securities under federal law, providing a boon to the Trump family.

President Trump and several of his family members are closely tied to crypto ventures, including the $TRUMP token, which launched just before his January inauguration. The coin currently boasts a market cap of about $2.4 billion, with its website claiming that 80% of the supply is held by the Trump Organization and affiliated entities.

WATCH: President Trump holds controversial private dinner for top investors in his meme coin

President Trump holds controversial private dinner for top investors in his meme coin

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GM takes over as the ‘#1 EV seller’ in Canada

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GM takes over as the '#1 EV seller' in Canada

After its electric vehicle sales more than doubled in the first quarter, GM claims it’s now the “#1 EV seller” in Canada. With a full lineup of 13 all-electric vehicles, GM sold more EVs than Tesla in Canada.

GM tops Tesla to become the #1 EV seller in Canada in Q1

GM’s electric vehicle sales in Canada surged by 252% in the first three months of 2025, with new Chevy and Cadillac models driving growth.

The Chevy Equinox EV led the way with 1,892 units sold, followed by the Silverado EV with 894 units. Cadillac’s new entry-level OPTIQ had a strong showing, with 615 models sold, nearly matching the 720 units sold of its first EV, the LYRIQ.

Even the GMC Hummer EV Pickup and SUV saw more demand, with sales up 232% (186) and 88% (252), respectively.

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Combined, the automaker sold a total of 5,750 EVs in Q1. According to GM, this was enough to top Tesla to become “the #1 EV seller in Canada.”

GM Canada recently posted on social media, saying, “We claimed the top spot as Canada’s #1 EV seller!” The news comes as registration data show that Tesla registered just 524 vehicles in Quebec in Q1, down 87% from the same period last year.

The steep decline in sales comes after the Quebec government paused federal EV incentives from February to April 1st. Canada also paused its iZEV rebate program in January, which offered up to $5,000 on the purchase or lease of an EV. Like the US federal EV Tax credit, it was designed to be used at the point of sale to help lower prices.

GM-#1-EV-seller-Canada
Chevy Equinox EV LT (Source: GM)

GM also registered significantly fewer Equinox and Blazer EVs in Quebec during the quarter. Despite higher year-over-year (YOY) sales, GM’s electric vehicle (EV) sales were down considerably from the over 15,000 in Q4 2024.

GM-#1-EV-seller-Canada
Cadillac OPTIQ EV (Source: GM)

The American automaker will continue to expand its lineup with the launch of the new Cadillac Escalade IQL, Lyriq-V, and Visiq.

By the end of the year, we also expect to get our first look at the next-gen Chevy Bolt EV with deliveries starting in 2026.

Electrek’s Take

GM is building momentum with new models rolling out, which now cover nearly every segment. In the US, GM surpassed Ford and Hyundai Motor, including Kia, to become the second-largest seller of EVs last year.

Chevy is now the fastest-growing EV brand in the US. The new electric Equinox, or “America’s most affordable 315+ miles range EV,” as GM calls it, is quickly becoming a top seller. The Blazer and Silverado EVs are also gaining traction.

Cadillac reported its best first quarter since 2008, with retail sales increasing by 21%. After delivering the first models in Q1, the entry-level OPTIQ is off to an impressive start with 1,716 units sold.

GM will top off its US electric vehicle lineup with the next-gen 2026 Chevy Bolt EV due out later this year or in early 2026.

Source: GM Authority, GM Canada

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