by Dylan Brewer
This June, New York City’s government and utility urged households to conserve electricity during an extreme heat wave with temperatures reaching 100 degrees F.[1] People were asked to set air conditioners to 76 degrees, to avoid using more than one air conditioning unit, and to delay using electricity-hungry appliances during peak cooling hours.
The big concern is that when every air conditioning unit is running at full blast, electricity demand can exceed total generating capacity and force the utility to implement rolling blackouts. These rolling blackouts avoid a total system failure but leave people without access to cooling and other electronics as temperatures reach dangerous levels.
As temperatures peak in the United States during the coming weeks,[2] utilities and city governments may follow suit with similar requests for voluntary conservation. Voluntary requests for conservation in the United States are part of the standard energy emergency playbook and go back at least to President Carter’s request for Americans to reduce heating temperatures during the 1977 energy crisis.[3]
So, do voluntary conservation requests work to save energy and prevent blackouts?
Why Would Voluntary Conservation Work?
First, why do utilities ask for voluntary conservation, and why would anybody voluntarily turn down their air conditioning unit during a heat wave?
Economists would point out that higher prices are normally what get us to use less of something that is scarce. When the price of gasoline goes up, we take fewer trips or wait to fill up if possible. When the price of gasoline is low, we are less concerned with how much we use.
Most residential energy contracts have fixed prices that only change yearly. Even those that have variable prices typically do not allow prices to freely rise with the wholesale price of electricity or natural gas. In an environment where energy-dependent appliances are ubiquitous, non-economists balk at the idea of allowing energy prices to rise and fall based on scarcity. Some people even go as far as suggest that access to electricity be considered a human right.[4]
So, when there is an energy emergency like a heat wave or polar vortex, the residential price of electricity or natural gas does not rise as it would in a typical market and then curb consumption. Instead, utilities seek to find other ways to get people to conserve.
This is where voluntary requests for conservation come in. Instead of raising prices, a utility or government official can psychologically reward conservation by asking people to “do their part” and save energy. Economists would describe this as being similar to a conservation subsidy where the payment is the warm glow people receive from contributing to the public good. Alternatively, people may feel guilty for not contributing to the public good.
However, there are all sorts of problems with voluntary requests to conserve. The emergency request might not reach everybody in time or may not be sufficiently motivating for some (or many) people to change behavior. But when a utility is facing the potential of rolling blackouts, an appeal to conserve might be the last opportunity in their toolkit to avoid this outcome.
The Evidence
Many economics studies have examined the effectiveness of “nudges” and other appeals for voluntary conservation.[5] In my own research, I wanted to understand how well voluntary requests for conservation could work in real energy emergencies.
Two of my papers use smart thermostat data to examine how well households respond to emergency appeals to conserve energy. In the first paper, my co-author Jim Crozier and I examine a 2019 polar vortex in Michigan where temperatures fell to -12 degrees F.[6] At the same time, a fire at a natural gas compressor station resulted in a sudden natural gas shortage on the coldest day of that year. The utility requested that households reduce thermostats to 65 degrees F and broadcast that request via a cell phone alert using the state’s emergency wireless alert system (the same system that delivers amber alerts to cell phones).
Partnering with the smart thermostat company ecobee, we found that 11 percent of households complied with the request, reducing thermostat settings by 1 degree F, on average. While an average of 1 degree may seem small, we estimate this to have resulted in a 6% reduction in energy consumption. In fact, we find that the largest reductions in thermostat settings began as soon as five minutes after the cell phone alert went out. Not bad, Michigan!
But before we get too excited about voluntary conservation, it is important to understand that not all emergency appeals work. In fact, I find less encouraging results with “routine” conservation requests.
In a working paper of mine coauthored with Maghfira Ramadhani, Ph.D. student and EPIcenter Affiliate, and Soren Anderson (Michigan State University), we examine how households responded to California’s Flex Alert program that asks households to conserve during energy shortages by setting the air conditioning thermostat to 78 degrees F or higher and to avoid using major appliances. We partnered with ecobee again to obtain households’ thermostat settings throughout the day and paired this data with information on when requests were made for conservation during a heatwave in California in 2021.
During the heat wave, households received requests to conserve energy for six days in a row, asking them to set their air conditioning thermostats to 78 degrees F during peak hours. We estimate no statistically significant effect of these requests on thermostat settings. However, on the seventh day, a cell phone alert was issued similar to the Michigan case. After the cell phone alert, we estimate that households reduced thermostat settings by 0.4 degrees F on average, again a small effect, but one that resulted in a 4% reduction in energy consumption.
We also obtain data from California households that voluntarily enrolled in programs that automatically override the households’ thermostat settings during an energy emergency. In contrast to the households that just receive flex alerts, these households conserved two to three times more energy than the average household!
Improving Emergency Conservation Programs
My findings point to a few things. First, the average household is not that responsive to emergency appeals. Second, any meaningful compliance with an emergency appeal likely requires an alert on a wide-reaching and official platform such as the wireless emergency alert system. Third, improvements in messaging, the use of price incentives, and automation have the potential to dramatically improve energy conservation during emergencies.
Some field experiments have demonstrated that price incentives can be five times stronger than appeals for voluntary conservation.[7] Run-of-the-mill and repeated requests for conservation fail to inspire action. Utilities and governments should work to improve emergency messaging capabilities and save emergency messages for truly dire emergencies to avoid desensitization.
Finally, technology like smart thermostats allow for automated conservation programs that have the potential to be much more effective, as in the California case. These programs exist, but many have low enrollments. For many people—me included—the thought of somebody overriding your home thermostat is the start of a dystopian nightmare. To make these programs work, utilities should purchase the right to control a thermostat from customers. That way, only customers who feel like the trade is worth it will participate, which has additional beneficial implications for the theoretical economic benefits of such a program.
[1] https://www.wunderground.com/history/daily/us/nj/teterboro/KTEB/date/2025-6-24
[2] Most of the United States sees its hottest day come between late July and early August: https://www.ncei.noaa.gov/news/when-expect-warmest-day-year
[3] Luyben, Paul. (1982). “Prompting Thermostat Setting Behavior: Public Response to a Presidential Appeal for Conservation.” Environment and Behavior, vol 14(1). https://journals.sagepub.com/doi/10.1177/0013916582141007
[4] https://energyblog.ethz.ch/human-rights/
[5] For a nice review, see Carlsson, Fredrik, Christina Gravert, Olof Johansson-Stenman, and Verena Kurz. 2021. The use of green nudges as an environmental policy instrument. Review of Environmental
Economics and Policy 15 (2): 216–237.
[6] Brewer, Dylan and R. Jim Crozier. (2025). Who heeds the call to conserve in an energy emergency? Evidence from smart thermostat data. Journal of the Association of Environmental and Resource Economists, forthcoming. https://www.journals.uchicago.edu/doi/10.1086/735535. Working paper available https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4360751
[7] Ito, Koichiro, Takanori Ida, and Makoto Tanaka. “Moral Suasion and Economic Incentives: Field Experimental Evidence from Energy Demand.” American Economic Journal: Economic Policy, vol. 10(1). https://www.aeaweb.org/articles?id=10.1257/pol.20160093