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How colored LED lights can make you cut back on kilowatts
About half of all electricity is wasted — which means there are big climate wins to be made in solving it. Displaying energy consumption with a light that glows red when people using too much, and green when they use less, gets people to reduce their energy use without even noticing they are doing it.
Environmentalists often decry that asking people to “switch the lights off” is too simple an ask to stop the climate crisis. Meanwhile, about half of all electricity is wasted and 1900 gas and 241 coal power stations across the USA burn fossil fuels to create the kilowatts that power all those lights, appliances, and HVAC systems.
I spoke with professor of cognitive psychology, Jaap Ham, on the How to Save the World podcast about his research showing that colored light (red light=bad, yellow light=ok, green light=good) is one of the most effective ways to influence people to reduce their energy consumption. Here’s what he had to share.
1. It’s called “Persuasive Technology”
All around us technology is designed to influence our behavior. It comes in the form of smartphones notifications, big screens, little screens, outdoor screens, audio chimes, colored LED lights, digital smiley faces, text messages, or any way that technology can be used to try and push someone to do something. It might be the chime that reminds you to put your seatbelt on, an app that notifies you of your sleep patterns, or an electronic speeding sign that displays your car’s speed and asks you to slow down.
2. We need feedback of the environmental impact of our actions
It can be difficult to figure out how to best reduce one’s environmental impact when you don’t know the impact of any appliance, product, or activity. How many liters of water did you use in your last shower? How much waste does your company send to landfill each week? How many square feet of green space did your city add in the last 12 months? No one knows.
It’s critical to weave this feedback into daily life to show people (and cities) the impact of their actions— and right now — we live in a feedback dead zone where the numbers describing our environmental impact are almost non-existent — or at least difficult to figure out.
Design tip: What is the environmental consequence of this action?
3. Feedback needs to be immediate
There’s a huge problem in the way we ask people to change their energy consumption — rarely systems are installed that communicate energy use as it happens. An electricity bill sent once a month is too long a delay in the feedback loop. Imagine if you received a signal for pain 30 days after you banged your knee into a table — your body’s pain system wouldn’t be very effective at protecting you!
Feedback works best when it is real-time — and these feedback systems are actually quite rare. I’ve seen them installed only in an occasional commercial building. Smart meters need to be designed to show real-time energy consumption to building occupants — and currently, they don’t do this.
3. Feedback needs to be in a time and place for action
There’s a reason why educational videos, books, and guest lectures about climate change tend to not affect behavior — it’s because these messages don’t happen where the behavior occurs.
Designing for behavior means a signal needs to happen at the time at the place the behavior is happening. This could mean installing behavioral interventions like stickers, colored lights, reminder signs, or display screens on appliances, cars, offices, or retail stores at the point at which you want people to do something.
4. Kilowatts can be shown as colored light (not in numbers)
Engineers will naturally want to describe kilowatts with a number or a chart, but data can be easily communicated with color only. Colored LED lights could be a missing link in communicating energy feedback to people because they are low cost, easy to program, and highly energy efficient.
5. Colored lights works better than charts or numbers
Professor Ham’s research shows that a red, orange, or green light communicating kilowatts of energy consumption got 23 percent more energy savings than showing the same data in numerical form.
Colored light is effective because other kinds of feedback like charts, robots, numbers, apps, and text messages require a lot more of a person’s cognitive resources to interpret. People are often busy and can’t devote the mental energy required to absorb the data.
This is why apps and browser software might fail to drive a behavioral response — because it requires a person’s singularly focused attention which is a scarce resource.
The mental energy it takes to understand something is called “cognitive load” — and when it comes to driving behavior, cognitive load is bad. Professor Ham says that additional cognitive load leads to slower mental processing.
It reminded me of a marketing slogan I saw recently — “If you confuse, you lose.”
5. We need “ambient feedback” on the wall (not in apps or websites)
The superpower of colored light is that it can be interpreted by a person while they are simultaneously doing something else. You can cook dinner, drive a car, or write an email — all while noticing the color of the light and responding to it.
That means the color needs to be broadcast in the ambient environment (not on a browser or smartphone) from places like walls, light switches, elevators, street signs, and cars. It’s called “ambient persuasive technology.”
6. People still save energy even if they don’t consciously notice the light
The fascinating thing about ambient colored light is that people still save energy when they don’t consciously notice the light. Ham’s research also tested showing people a smiley or frowny face for a 50-millisecond flash — that’s so fast is it undetectable to the human eye. The subliminal smiley faces still got people to save energy.
7. Negative feedback (red) works better than positive feedback (green)
Ham’s research showed that negative feedback (the red light) was more effective than positive feedback (the green light) in getting people to reduce energy use. He said this happens because we feel negative feedback (such as being scolded) more intensely than we experience positive feedback.
He suggests that even though negative feedback is the most powerful way to get people to respond, we should be somewhat restrained with it because people might reject the whole system if they feel overly criticized.
8. The kilowatt’s time of day determines the carbon emissions
It’s not just about the net kilowatt hours — the time of day that electricity is produced matters, too. For example, in California, electricity is frequently 100 percent carbon-free during the day. As soon as the sun sets (or it gets hot enough for AC), seventy-four gas power stations (known as “peaker plants”) fire up to make the electricity that solar panels can’t provide. You can see these real-time emissions on the Energy Lollipop Chrome extension.
9. Educating people about climate change (mostly) fails to get people to do anything
Behavioral studies show that educating people about climate change generally fails to drive behavior. It works to help people learn and it helps people to care, but it generally doesn’t translate into action.
Education experiences like watching a documentary or reading a book fail to drive behavior because they aren’t happening at the time and place the behavior is occurring. They also don’t show the feedback of an individual person’s impact. Educational experiences fail at hitting the main human motivational drivers as told by expert behavioralist Robert Cialdini— social norms, conformity, and compliance.
Instead of designing for “education” or “concern,” we need to design for “agency” and “self-efficacy.”
10. Millions of electric vehicles are about to load up the grid with no system to help people avoid peak emissions times
The electric vehicle revolution has the potential to provide the biggest environmental win of the century— but only if people can charge their EVs in the daytime from solar power. If EVs are charged after dark, these supposedly “green” cars will be almost entirely powered by gas peaker plants and coal power stations.
Colored LED lights can be easily applied to EV chargers to glow red when the carbon intensity of the grid is highest to deter people from charging during these peak times. Companies like WattTime and ElectricityMap provide APIs of real-time CO2/kWh data for most of the world’s developed regions.
11. Using colored light to show community-scale emissions
Colored light feedback doesn’t need to only show the emissions of an individual house or office. Aggregate emissions can be displayed outdoors for a campus, a neighborhood, or a city emissions — and installed in a public setting using the same ambient colored light principles. It’s called “community-scale ambient feedback.” The unconscious power of colored light is likely to influence thousands of passers-by to reduce their kilowatts, often without them taking conscious action to do so.
We need to rapidly deploy the means of influencing millions of people, at scale, to reduce emissions. Colored light is a low-cost and technically straightforward way to drive the behavior responses we will need to help close hundreds of gas and coal power stations around the world.
Let’s not leave colored LEDs to only inhabit gaudy Christmas decorations and Burning Man art. The colored LED, if used persuasively, could literally light the path to a climate-friendly future.
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