News Reporter: Climate Coach: Americans could heat their water with the sun once again

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Down-to-earth advice for life on our changing planet.

(Shutterstock / Roman023_photography)

By Michael J. Coren

Welcome. This week, grizzlies in Montana and tornadoes in February. But first, can Americans heat their water with the sun once again?

To read the full column at The Post, click below.

Click here to read the column

In the early 1980s, my dad installed a solar thermal panel on our roof in Florida. For a 5-year-old, the big black square looked like a portal into the future. The device, essentially a glass box with metal water pipes running through it, converted sunlight into hot water. By trapping solar energy like a greenhouse, it heated the water to a scorching 180 degrees Fahrenheit.

It furnished most of the hot water for a family of four. "We had no trouble with it," my dad tells me. "It was still working when we sold the house 10 years later."

But today, hardly anyone is using these solar water heaters even as photovoltaic panels have popped up on the roofs of nearly 4 million American homes.

Theoretically, solar thermal offers a big opportunity to slash emissions, while cutting the average utility bill by $400 to $600 per year, estimates the Energy Department.

Is solar thermal right for you? Here's what you need to know.

What is a solar water heater?

The basic principles haven't changed much since the first solar therm water heater, the "Day and Night Solar Heater," was commercialized in the United States around 1909. It featured a coil of copper pipe in an insulated box under a pane of glass. As water in the pipes was heated by the sun, it flowed into a storage tank supplying the house.

Today's more sophisticated models can replace 50 percent to 70 percent of the fossil fuels needed to heat water at home because they are so efficient, converting 60 to 70 percent of the sun's energy into heat (compared to about 24 percent with solar photovoltaics which generates electricity.)

Are they popular?

Back in the 1980s and 1990s, solar water heaters were poised to be a major player in America's energy mix. Americans had installed nearly 1 million solar thermal systems by 1990. But several factors doomed their expansion: unskilled installers and shoddy designs, plunging natural gas and solar photovoltaic prices, and, crucially, the end of tax incentives in 1986.

Within a few years, the industry had nearly collapsed. Today, these systems represent a tiny fraction of the potential, supplying 0.4 percent of today's global energy demand for domestic hot water.

Do solar water heaters still make sense?

Yes — in some cases. They can work almost anywhere the sun comes out, even in countries as far north as Canada and Denmark, solar thermal energy warms millions of homes with district heating systems. But you'll have to figure out if they make economic sense for you.

In Hawaii, where electricity retail prices are nearly triple the U.S. average, and there's constant sunshine, conditions are ideal for the technology. The state's utility estimates one in four single-family homes now heat their water with the sun.

But they can be right for you too. To learn more, click below.

Click here to read the column

Write me with your questions at climatecoach@washpost.com. I read all your emails.

Field Sample

In America, they are often treated poorly, ignored in favor of Asian or European immigrants. But in Parisian gardens, American expats enjoy pride of place, write Sean Solomon and Isabelle Dijols.

We're of course talking about ornamental plants.

Solomon and Dijols, two urban environmental restoration advocates who are helping restore Morris Park in Philadelphia, toured Paris in 2011 capturing images of often-ignored all-American plants that Parisians treat as exalted specimens.

Below is a picture of an American sweet gum, a native to the eastern United States that grows 60 to 100 feet. The couple also found Virginia creeper, tulip poplar and many others. As I wrote in my last column about tidy wildlands, we just need to learn to love our species as much as others do.

Sweetgum in the Paris suburb Le Raincy (Sean Solomon and Isabelle Dijols)

Learning Curve

Flowers are one of the most climate-damaging perishables we ship worldwide, write Amanda Shendruk and Michelle Kondrich in The Post's Opinion section. Most global commerce travels by ship, but many flowers fly, especially roses, chrysanthemums and carnations. That means a bouquet of imported flowers generates more emissions than an 8-ounce steak raised on deforested land in Brazil.

Environmental impact of imported items in British grocery stores Carbon dioxide equivalent (CO2e) Source: Mike Berners-Lee, "How bad are bananas? The carbon footprint of everything"

While some companies in the $34 billion global flower industry are experimenting with shipping their most popular products by sea, many other species, often lesser-known, grow closer to home on small farms across the country.

Here are some good bets this Valentine's Day or any other day: sunflower, snapdragon, peony, zinnia, dahlia, lisianthus, cosmos, Sweet William and ranunculus.

Read their delightful illustrated guide here.

The Second Degree

You had thoughts on backyard biodiversity.

Patty in Towson, Md., decided to hold her own native garden contest after reading "Nature's Best Hope," by Doug Tallamy, one of the experts I interviewed. "We'll be holding it again this year," she says. Others suggested that instead of defaulting to a full lawn, you think about where you actually want a grassy area, such as around a seating area. Then work on transforming the rest.

And when you do mow, keep it 4 inches high to give creatures a chance to thrive — a reader noted one Cornell researcher designed a native grass lawn that only needs to be mowed twice a year, and requires no pesticides or fertilizer. I also loved this explainer on "soft landings" of native plants and flowers under keystone trees, a beautiful way for insects to get a good start on life once they enter their next stage after dropping from the trees.

Others warned that the perennial native yard, while beautiful, is not maintenance-free. "I didn't need to mow, water or fertilize, but deadheading in spring, leaf removal and pruning are a must to keep the lot neat enough to pass muster in a residential neighborhood," wrote another reader.

Here are some resources to get started on your own garden:

The National Wildlife Federation's native plant finder
Native plants database (Audubon)
Keystone species (Homegrown National Park)
Search online for your local master gardeners and native plant societies.

On the Climate Front

From The Post:

Famed climate scientist Michael Mann won a million-dollar verdict against right-wing bloggers.

El Niño's end may be near. Here's what's coming next.

You may not be getting the fish you paid for. Here's how to spot seafood fraud.

It's so warm in Wisconsin that it just had its first-ever February tornado.

From elsewhere:

Grizzly bears are returning to Montana's Bitterroot mountains on their own decades after the Bush administration blocked their reintroduction, according to HuffPost.

After they were nearly wiped out, California sea otters are now restoring their own coastal habitat, NPR found.

Bluefin tuna are back in British seas by the thousands, says the Guardian.

Plastic food packaging was linked to 10 percent of preterm births in 2018, Grist reports.

Day Johnston of Kentucky has grown something that, to my eye, looks like a piece of art. "Wild grass island on a sea of vinyl roofing," he writes. "It's a box of dirt growing whatever the wind blows in: 25 years and counting."

Are you growing any art? Send me your photos and stories at climatecoach@washpost.com.