In a heat wave, some people wait too long to turn on the AC. Smart data use could help
When Destenie Nock was a graduate student studying engineering at the University of Massachusetts, Amherst, she didn't have air conditioning at home. One summer in the midst of a heat wave, she began experiencing symptoms of heat illness without many options for what to do about it.
"I was taking cold showers every three hours," Nock said. "I was very dehydrated. I ended up going into my office to go sleep. But I realized there are a lot of people that don't have that luxury."
The experience sparked a research program she's now taken on as a professor of engineering and public policy at Carnegie Mellon University in Pittsburg to study how energy use data might help alleviate inequalities in access to air conditioning in places like Phoenix, where that difference can mean life or death.
Phoenix made international headlines this summer for record heat. High temperatures at or above 110 degrees Fahrenheit for all but one day of July set a new record for the hottest month in a U.S. city. Lows were also sweltering, breaking the overnight record on July 19 when temps failed to drop below 97 degrees at Sky Harbor International Airport.
An overwhelming majority of scientists agree that recent extreme heat events have been made much more likely by climate change, a result of heat-trapping greenhouse gases emitted into the atmosphere when fossil fuels are burned for energy. Solutions include reducing energy use, improving efficiency and transitioning the grid to renewable sources like wind and solar.
In Phoenix, 98% of homes have an air conditioning unit installed, making its housed residents generally more prepared for heat waves than people living in locations like the Northeast where Nock went to school. But this summer's extremes still took their toll on Phoenix residents, who weather the highest annual cooling requirement of the nation's 50 largest cities.
As of its Oct. 28 heat report, the Maricopa County Department of Public Health has confirmed 569 heat-associated deaths so far in 2023, already far surpassing 2022's record-setting 425 heat-related fatalities. Members of disadvantaged groups like the unhoused and the elderly, as well as disabled people, minorities and those with low incomes typically account for more than their share of these totals.
A quarter of 2023 heat deaths, 141 people so far, occurred indoors, a number that Arizona State University researcher Patricia Solis has said previously "should be zero." Of those, 106 died in situations with nonfunctioning air conditioning, two lacked electricity and 13 were in residences without cooling units. Fifteen more had a functioning air conditioner but weren't using it when they died.
Nock thinks all of these indoor deaths could, and should, be prevented in the future — even as climate change jacks up the frequency and intensity of heat waves — through smart data use and policy improvements. That goal drove a research project she and colleagues from Carnegie Mellon, the University of Maryland and the Resource Planning and Development department at Salt River Project, one of Phoenix's major utilities, recently published in the scientific journal Energy Policy.
The researchers compared daily smart-metered electricity consumption data from nearly 6,000 Phoenix households between 2015 and 2019 with the amount of energy they would expect each home to use given recorded outdoor temperatures and information on the home's size, age and type of cooling unit collected as part of a 2017 SRP customer survey. They then identified households that seemed not to be using enough energy during a heat wave — perhaps to keep bills low or due to a broken unit — and might have been at risk of deadly indoor heat exposure.
"If someone has a broken air conditioner or if someone is not using their air conditioner during a heat wave, I can tell you what address to go call," Nock said. "I can tell the utility the account number that they need to reach out to to ask them, 'Hey, are you OK?' And I think that's what we need."
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The homes flagged by Nock's analysis as dangerously limiting use of air conditioners and most likely to benefit from wellness checks during heat waves are, the researchers found, often those of already vulnerable and energy burdened groups. By simulating how the energy demand for cooling might change under future climate scenarios, they also determined this gap is likely to increase.
A household is considered "energy burdened," Nock said, if its occupants spend more than 6% of their monthly income on utility bills and "severely energy burdened" if that cost rises to 10%.
Looking exclusively at the summertime cooling load, they found that the energy required to maintain preferred indoor temperatures may increase by between 16% and 38% in Phoenix by 2070 under a projected high climate warming scenario. Households with the lowest incomes, under $15,000 in this study, could see their energy consumption go up as much as 45%, on average, as they try to cool less efficient structures like mobile homes or poorly-constructed apartments, compared with a 33% rise in better-insulated residences typical of those with incomes over $150,000.
For people over 65, the electricity required to maintain a livable indoor space could jump 49%, compared with 36% for people aged 45-54, due to differences in the homes and appliances often owned by these age groups. Older people are physiologically more vulnerable to heat and can also be on fixed incomes that require them to limit spending on air conditioning. Victims over 65 account for 31% of heat-associated deaths in Maricopa County so far in 2023.
Projected consumption results were mixed for the analyses of racial and ethnic minority groups, with the burden on white households increasing more slowly than that on Hispanic households but faster than in Black and Asian households. But since baseline energy use is highest among white households, those residents may have more wiggle room before experiencing discomfort indoors.
The escalating energy burden climate change may impose on disadvantaged groups is especially concerning given that those who are less affluent or mobile generally already maintain higher indoor temperatures and have fewer options for seeking alternative, cooler shelter during a heat emergency.
"I have been able to find that there are some households that wait until the average outdoor temperature is above 78 degrees Fahrenheit in Phoenix to turn on their air conditioners, which often means the maximum daily temperature is 90 degrees. The federal government recommends people set their thermostats to 70 degrees," Nock said. "This is all very useful in terms of trying to alleviate poverty."
But when it comes to the extreme cooling demand of extreme heat, climate change threatens to also function as a grim equalizer when the energy grid strains toward potential failure. A study published in May estimated that a blackout during a five-day heat wave in Phoenix could send 800,000 people to the emergency room, a dire situation that city officials, medical centers and utilities are eager to avoid.
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This summer, on July 18 between 4 and 5 p.m., SRP delivered its highest-ever system demand of 8,163 megawatts, nearly 500 megawatts more than what the utility forecast its peak demand would be for 2023, utility representatives told The Arizona Republic.
SRP handled this and avoided a blackout, in part, by tapping into the "demand response capacity" created by customers enrolled in its smart thermostat program, which offers a $100 rebate on approved smart thermostats to customers who agree to let the utility remotely bump up their indoor temperature by a few degrees during "conservation events" to help manage high strain on the grid.
The utility has so far enlisted more than 85,000 thermostats in 60,000 Phoenix homes, and it tapped this connection to dial back residential energy use on nine days in 2023. Since customers also control their own smart thermostats remotely, they can always just bump the temperature back down in their homes. But allowing the utility some control over how much electricity air conditioners pull from the grid during a heat wave can help manage the risk of blackouts and ensure there is enough cooling to go around.
As a last resort during an energy shortage, SRP told The Republic it would conduct rotating outages, or "rolling blackouts," in its service area that could last 20 to 30 minutes and would not affect hospitals or airports. The utility might also purchase additional energy supplies on the open market, suspend service to interruptible customers and ask the community to voluntarily reduce energy use.
'The thing is, most people don't want to be poor'
Using data to identify households at risk of excessive indoor heat or cold exposure as well as those who could be asked to scale back to avoid a grid failure has myriad benefits for society, Nock said. Her startup company, People's Energy Analytics, offers her services to utilities seeking to locate inefficiencies as well as those who might benefit from knowing about assistance programs before they get behind on payments.
"One of the challenges that I see in the U.S. is that a lot of customer programs are self-signup," Nock said. "You have to kind of say, 'Hey, I'm poor.' And then you have to go prove that you're poor, and then you have to go sign up and ask for that. And the thing is, most people don't want to be poor."
Nock wants to leverage her analyses to circumvent this requirement for those in need to self-identify. She hopes to improve efficiency not only in energy use, which is the most straightforward path to mitigating suffering related to climate change, but in identifying those currently at risk of insufficient indoor cooling.
"We have an opportunity to say, 'Hey, you know, you're living in an older house. You're not turning on your air conditioner until it's 110 degrees outside. Here's all the programs that you will qualify for that will allow you to keep you and your kids safe.' That is, to me, what we should do with all of these smart meters and all this household data that we have."
SRP offers several services designed to make sure low-income families have access to cooling when they need it. The utility calls customers in jeopardy of becoming past due on bills to work with them on price and payment plans and help connect them with home improvement options, such as the federal weatherization assistance program announced in Arizona this spring. A partnership with the Salvation Army offers energy assistance to those in need. And the "Safety Net Program" allows customers to designate a friend or family member who can be notified if their bill becomes past due.
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Customers with medical conditions who rely on electricity to operate life support equipment can avoid disruptions in service by calling SRP to enroll in its "Medical Preparedness Program." The utility also said it employs bilingual "active listeners" to identify callers who might benefit from welfare checks and refer that need to local law enforcement.
Answering the call to help
Phoenix's Office of Heat Response and Mitigation also has a program designed to check on residents who might be vulnerable to excessive indoor temperatures. But it has largely failed to launch despite this summer's record heat extremes.
Dave Hondula, who directs the heat office, said he's not sure why their "Cool Callers" program hasn't taken off. The initiative, which started last year, recruits volunteers for two two-hour shifts per week to call at-risk residents, particularly on days when the National Weather Service has issued an "Extreme Heat Warning," and connect them with emergency medical and financial support services as needed.
The program requires volunteers to pass a background check and commit to 100 hours of service, including training.
But that's not the problem. Hondula said they've had plenty of volunteer interest, which he sees as a positive reflection of the community's desire to help limit indoor heat deaths.
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The obstacle is that fewer than 20 people have signed up, or were signed up by family members, to be called. So last summer he made all of those wellness check calls himself, except for a few that needed to be conducted in Spanish. One call resulted in a resident gaining access to a utility assistance program.
“It feels like the potential is so high for something in this space, and the logistics are not all that complicated, but we haven’t struck quite the right message to have sufficient enrollment," Hondula said. "Do we need to run through a community partner? Do we need to go through different advertising channels or have different conversations about it? Trying to crack this nut is certainly high on my list."
Hondula hadn't heard about Nock's data-based approach, but views it as a promising strategy and said his office has been discussing similar ideas.
"So many of the indoor heat-associated death narratives have this unfortunate dimension of, ‘If only I had known, I could have acted,’" he said. "There are so many ways we’re hyperconnected with technology but we haven’t fully leveraged that for the benefit of public health. I think this domain is exactly one of those areas and we have been exploring some related questions."
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Nock's study concludes with three recommendations for communities that want to prepare for the increased energy demand of a warming climate and the unequal impacts it is expected to have.
First, the authors advocate for continuing to advance federal regulation of efficiency standards in air conditioning units and expanding initiatives like the Weatherization Assistance Program and the Low-Income Home Energy Affordability Program to reduce overall energy insecurity.
Second, they point to a need for more research on identifying households in need of utility bill assistance and the funds required to support them. They encourage broader sharing of aggregated electricity usage information kept by cities, utilities and residents and suggest that mandating this data transparency may enable communities to make smarter investments. (One reason Nock gave for conducting this study in Phoenix was SRP's unusually high-quality data and willingness to share it.)
Finally, Nock and her co-authors point out that upgrading households with more efficient cooling units like heat pumps does not automatically translate into energy savings in the absence of best practices with thermostat use and overall building efficiency. They recommend working alongside at-risk groups to develop training resources on how to maximize savings.
"I believe that we can be very intentional about finding people before they die," Nock said. "I mean, that's the whole point, finding people before they're at risk."
"I just always think about my younger self. I was so convinced I was not poor, that I didn't need help, because I was handling it. And in reality I wasn't, and if that heatwave had lasted three weeks instead of five days, I could have been way worse off. Now that I'm older, I think a lot about my 24-year-old self who thought that she had it all together."
Joan Meiners is the climate news and storytelling reporter at The Arizona Republic and azcentral.com. Before becoming a journalist, she completed a doctorate in ecology. Follow Joan on Twitter at @beecycles or email her at joan.meiners@arizonarepublic.com. Read more of her coverage at environment.azcentral.com.
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This article originally appeared on Arizona Republic: Energy data, 'cool calls' may help at-risk people survive indoor heat
