Harvey Sachs has worked on energy efficiency in buildings for three decades.
His wife is a systems engineer with an advanced degree.
Neither has mastered their home's programmable thermostat.
Here's a clue as to why: The instruction manual is more than 150 pages.
Sachs recalls that when Apple introduced Macs to the media, the computers had no manuals. "Why should a thermostat be harder?"
Therein lies the sad history - and the roots of a promising future - of a device that is vitally important. Heating and cooling consume about 50 percent of household energy use, and thermostats control temperature.
Time was, people had to change the settings by hand.
Programmable thermostats were supposed to make saving energy, and money, easier. You could set the control to heat the house in the morning, reduce the temperature in the day if no one is home, bring it back up for the evening, then lower it again during the night.
If properly used, the federal government's Energy Star website contends, a programmable thermostat can cut 20 percent off a family's heating and cooling bill. Or, on average, about $180 a year.
Energy experts assumed that was happening. By the late 1990s, the devices were being sold at low prices, or even given away, by utilities as a way to help people save energy, said Sachs, a senior fellow with the American Council for an Energy Efficient Economy, a nonprofit advocacy group.
Turns out they were wrong.
Several studies - one was titled "Programmable Thermostats That Go Berserk?" - found that either the programmable thermostat didn't make any difference or, worse still, it led to more energy consumption.
People would think they had the device turned down, and the house would be 80 degrees in winter.
In a study published last year, Alan Meier of the Lawrence Berkeley National Laboratory in California and his colleagues found that even though 85 percent of the respondents contended they were using the programming features, photos proved that 45 percent of the thermostats were actually on "hold" - unprogrammed.
In interviews, the researchers heard common themes: "I don't touch it." "I don't want to mess it up."
Then Meier's group set up thermostats in the lab and brought in 29 people to try to operate them.
The first task was to switch the thermostat from "off" to "set heat." Some people did it in less than 10 seconds.
But 26 percent weren't able to do it at all. Even though the researchers provided instruction booklets.
Energy Star had suspected as much.
The federal energy program sets efficiency standards for equipment, and products that meet the standards can carry the Energy Star logo.
In 2009, Energy Star suspended its programmable-thermostat program.
"Not that there was clear evidence they weren't" working as intended, said Abigail Daken, Energy Star's product manager for heating and cooling. "But there was not enough evidence that they were."
Now, Energy Star is working on a new thermostat initiative, and they're trying to devise a numeric rating for how easy something is to use. "That turns out to be a novel thing to do," Daken said.
And difficult. She can't say when the new program will launch, but the agency is aiming for this year.
Liz Robinson, of the nonprofit Energy Coordinating Agency in Philadelphia, still swears by programmable thermostats, which are key to its weatherization program for low-income residents.
"We love them. We're crazy about them," she said.
But the agency also offers a lot of education. And a hotline number is posted on each device so residents can call for help.
"As a result of that, we have gone from a headache to a home run," Robinson said.
For proof, she points to a recent study of a Philadelphia Gas Works conservation program. It showed that among other measures, including insulation and air-sealing, a programmable thermostat was the most cost-effective. For each dollar spent, it produced $20 in savings.
Now, the world of thermostats is changing.
Fortunately, some of the newest thermostats don't require much smarts on your part. They're intelligent all by themselves.
Take the Nest Learning Thermostat, developed by techies who had their roots in Apple and Google and Twitter. It's about the size of a hockey puck, and there are no buttons or arrows.
Since it's hooked up to your WiFi or other broadband, it tells you the time and date.
You start to use it like an old manual thermostat, and the thing gradually learns your habits. It knows when you leave for work, when your bowling night is, and whether you stay up for Saturday Night Live.
Away from home? You can change the settings with your smartphone.
I was suspicious. "So how many pages is the manual?" I asked company spokeswoman Kate Brinks.
There isn't one. Just "a little tips guide," she said. "It's very intuitive."
In the near future, Meier says, thermostats may control ventilation and humidity.
"Climate control" is the new buzzword. Although none of these devices is cheap, rising energy prices and falling technology prices should close the gap eventually.
Companies are syncing the thermostat with all manner of other "smart" household controls. Energy Star's Daken is seeing some thermostats as a function in a security-system control panel - which knows when you leave the house because, presumably, you've activated the alarm.
Last fall, Verizon came out with a total-house system that not only controls the thermostat, but also tracks energy use hour by hour and has the capability to turn on, or off, lights, appliances, security cameras, and more.
The system works with broadband connections, and Ann Shaub, director of consumer product management for Verizon, has become a monitoring junkie, constantly checking her smartphone to detect the energy goings-on in her home.
Once, she noticed an inexplicable spike and found out later that someone had left the refrigerator door ajar.
She can turn on the air-conditioning on her way home from the beach, punch in the security code to unlock the door for the cleaning service, or turn off her son's Xbox even if she's still at the office.
My programmable thermostat - I've made my peace with it, but let's hope I don't lose the manual - isn't anywhere near as fancy. But it does eliminate the need for one piece of household equipment.
At night, thanks to a champion feather quilt, we've programmed the thermostat to 55 degrees. In the morning, when the setting bumps up to 67, we wake up because it feels so hot.
No need for an alarm clock!
"GreenSpace" appears every other week, alternating with Art Carey's "Well Being" column. Contact staff writer Sandy Bauers at 215-854-5147, firstname.lastname@example.org, or @sbauers on Twitter. Visit her blog at www.philly.com/greenspace.