In a lighter vein, Shelton has also come up with a list of the "un-green" things that Americans feel most guilty about.
Topping the list is food waste, something a whopping 39 percent of us regret. (For good reason. One recent study concluded that the average family tosses about 470 pounds of food a year.)
Things at the bottom of the guilt scale? It bothers only 10 percent or less to run the dishwasher or clothes washer when it's not full, to goose the thermostat to be more comfortable, or to use chemical fertilizer on the lawn.
And when it comes to stigmas, we'd be more embarrassed getting caught tossing litter out the car window than cheating on our taxes. (But not as embarrassed as if we were caught shoplifting.)
Shelton's researchers do annual "pulse" surveys looking at what we buy and why, whether we make green changes in our lives and our homes, and how guilty we feel if we don't, which was the survey that came out last week.
Other things some of us feel guilty about - which is telling - are not turning off the lights when we leave a room (27 percent express remorse), not unplugging chargers or electronics when not in use (22 percent), not recycling things (21 percent), and forgetting to take the reusable bag to the supermarket (20 percent).
The statistics are based on online surveys of more than 1,000 respondents, with a margin of error of about three percent - enough for an accurate portrayal of the nation's green psyche, Head said.
Shelton uses the information to help companies market their products, but it shows the rest of us how far we've come.
And still have to go.
For instance, a survey about home energy found that Americans aren't making enough changes - such as installing insulation or high-efficiency windows - to make significant differences in utility bills.
Only 33 percent of respondents think they need a home energy audit - widely regarded by experts as an important first step - and fewer than half of those said they were likely to get one.
"Home energy audits continue to be the colonoscopy of energy efficiency," lamented Shelton founder Suzanne Shelton when the study came out. "Everyone should get one, but too few actually go through with it."
On the other hand, we're learning. After annual declines in the number of people who say they agree that climate change is occurring and that it is primarily caused by humans, the number rebounded this year to about 57 percent.
One thing that surprised the researchers is that "Made in the U.S.A." is becoming an environmental message for consumers.
Patriotic, sure. Good for the economy, yes. But green?
It turns out that people think products made here are subject to more stringent environmental regulations. They also think the United States is leading in sustainable product innovations. And they distrust products made in foreign countries - such as China - fearing they might contain toxic ingredients.
"It's this wonderful double whammy, supporting American workers and jobs, but also a sense of health and safety, that we hadn't anticipated," Head said.
Researchers thought there would be skepticism about green claims on products, but that depends. In years past, consumers said they knew if a product was green because "it says so on the label."
Now they read much more closely, checking ingredients on food or cleaners, and energy efficiency data on appliances.
Still, label-watchers often don't understand all the information.
Shelton has found that, when asked "what's the best thing to read on a food label," 68 percent say it's "all natural" or "100 percent natural" - vague and largely meaningless terms.
In contrast, only 54 percent say the best thing to see on a label is "organic" or "100 percent organic" - terms that are regulated.
Heed this, corporate America: People also make product choices based on a company's environmental reputation. They choose Newman's Own because of that company's give-back program to nonprofits (although that's more charitable than green). And they stopped buying gas from BP after the 2010 oil spill in the Gulf of Mexico, the poll shows.
But even with the best of intentions, life intervenes. Compromises are made.
Shelton researchers also asked which of three attributes - comfort, convenience, or the environment - a person would most often choose.
Each year, for five years in a row, the environment wound up at the bottom of the heap, getting just 27 percent of the nods.
"GreenSpace" appears every other week, alternating with Art Carey's "Well Being" column. Contact staff writer Sandy Bauers at 215-854-5147 or email@example.com, or follow on Twitter @sbauers. Visit her blog at www.philly.com/greenspace.