Save Energy, Save the World

With the climate strike in the news, you may be wondering how you can reduce your greenhouse gas emissions. Generating electricity to power our homes contributes to greenhouse gas emissions; so limiting your use of electricity will help lower your carbon footprint. Conserving energy can be done by using energy efficient devices, such as those rated by the Energy Star program, or by using devices less, for instance turning off the lights when you leave home.

We would all like to take the most effective conservation measures we can. However, it turns out that we are not always very good at knowing which steps are most effective. In the past, when people have been surveyed about how much electricity their appliances use, they weren’t always right.

Measuring our measurements

There are two basic ways we can evaluate energy use. First, we can rank appliances from the highest energy users to the lowest. Second, we can try to assign values to how many kilowatt hours (kWh) that a device uses. Kilowatt hours (kWh) are a unit used to measure energy use and you may recognize this term from your electricity bill.

Tyler Marghetis from Indiana University Bloomington and his colleagues recently published a paper that evaluates how people understand their electricity use. In order to conserve electricity, we need to understand it. They tested what people know about electricity use and what is the most effective way to teach people more about it. They wanted to find out what information to give people to help them make better decisions.

They tested two types of information to make our estimates about energy use better. They told the first group that a good rule of thumb to use is that “large appliances that primarily heat or cool use a lot more energy than people think they use.” For the second group of consumers, they gave them some actual values of energy usage to help them better estimate their electricity usage. The third research group served as a control and was not provided with any additional information. All three groups were then surveyed and asked to assign values to energy use for different appliances. The researchers then compared the survey responses against the true values. They also looked at the relative ranking of the values. For the ranking, they listed each appliance from highest to lowest electricity. Even if people got the values wrong, they might know that a washing machine uses more electricity than a lamp.

The estimates from the third (control) group had errors in both the ranking and the values assigned to appliances. Consumers in the second group, those given sample electricity usage values were the best at determining the energy usage values of other appliances. Consumers in the first group, who were told that larger appliances consume more energy, were the best at ranking the appliances. Overall, people in the second group were most accurate at determining energy usage values, but both groups that received information made more accurate

predictions than the control group.

Changing Behavior

Marghetis and colleagues also wanted to see whether these participants could determine the best ways to save energy. They gave the users different conservation options and asked them to pick the best one. For instance, they might have to choose between: (1) using a clothesline instead of a dryer; and (2) reading a book instead of watching 20 hours of TV. In this survey, the first group (with the rule of thumb) were the best at identifying how to save the most energy.

So…?

Giving people a rule of thumb about energy use enables them to make the best choices about how to save energy. Although this group did not predict energy use values the best, they were better at making smart choices. So if you are trying to take steps to reduce your energy use, just remember:

“Large appliances that primarily heat or cool use a lot more energy than people think they use”.

Citation:

Marghetis, T., Attari, S., Landy, D., 2019 Simple Interventions can correct misperceptions of home energy use. Nature Energy doi: https://doi.org/10.1038/s41560-019-0467-2 https://www.nature.com/articles/s41560-019-0467-2