The app said thirty-eight cents at 6:47. Red. I set my phone on the counter and finished cutting the cantaloupe.
My son was on the couch with his earbuds in, not watching anything, just lying there with his phone on his chest. He used to come into the kitchen around this time and say something about the heat. How it was stupid, how his friends' houses were cooler. He stopped saying that about a year ago. I don't know exactly when. I just noticed the silence one evening and realized it had been there awhile.
I brought him a bowl of cantaloupe and he took it without taking his earbuds out. Said thanks.
The living room was eighty-three according to the thermostat, which I'd set to eighty but the system couldn't hold it. CPS was cycling the compressor, twenty minutes on and ten off. The house hadn't truly cooled since morning.
I went down the hall to check on my mother.
Her room was the back bedroom, the one that used to be my son's before we moved her in three years ago. It had the window unit, a twelve-thousand-BTU Friedrich I'd bought for that room because it faced west and the attic above it held heat like nothing I've ever seen. The unit was running. I could hear it from the hallway, and when I opened the door the air was different. Cooler. Maybe seventy-seven.
She was in bed reading her tablet, propped on two pillows. Glass of water on the nightstand that looked like she hadn't touched it.
"You need to drink that."
"I'm not thirsty."
"I know. Drink it anyway."
She picked it up and took a sip, watching me over the rim like I was being ridiculous. She was seventy-nine. She took metoprolol for her blood pressure and oxybutynin for her bladder, and both of them worked against her in the heat. The metoprolol slowed her heart rate, less blood moving to her skin. The oxybutynin cut her sweating. Her doctor had explained it in April. I'd written it on a notepad and stuck it to the refrigerator and looked at it every day until I didn't need to.
I looked at her arms. Dry. Her face. Dry. That was what I'd learned to watch for. The absence of sweat was the warning. Her body wasn't trying to cool itself because the medications had turned that system down, and she couldn't feel how warm she actually was because that perception dims too, with age and the drugs. She'd tell me she was fine and mean it.
"How do you feel?"
"I feel fine, Elena. I'm reading."
"Okay."
I left the door open a crack so the cool air would leak into the hallway. Wasteful. I did it anyway.
Back in the kitchen I checked the app. Still red. Tier Three ran from five to eight on weekdays. At eight it would drop to Tier Two, twenty-two cents, yellow on the screen. At eleven it would go green. Eleven cents. That was when I'd turn the system down to seventy-six and let it try to pull the house into something a person could sleep in.
The battery was at seventy-one percent. About nine and a half kilowatt-hours. The window unit in my mother's room drew about one-point-two per hour. If the grid went down tonight I could run her room for almost eight hours on the battery alone.
That was the math I did every evening. That was what the battery was for.
My son knew not to plug his laptop into the wall during Tier Three. He charged it overnight, same as his phone. He knew to keep his door closed. He knew the frozen towels were in the chest freezer in the garage, rolled and bagged every morning. He knew all of this the way he knew how to lock the front door or take out the trash.
He was seventeen. For him this was just what evenings were. You didn't run the AC hard until eleven. You ate cold food. You checked the app the way you checked the weather.
I figured the part that sat with me was that he'd stopped registering it as something worth saying out loud.
I ate my cantaloupe standing at the counter. The kitchen window faced west and the blinds were down but I could feel the heat through the glass, the last hour of sun pressing in. The cantaloupe was cold from the refrigerator and I stood there eating it and not thinking about anything for maybe two minutes, which was nice.
Saturday had been the cookout. Juneteenth weekend. The family two doors down had set up tables in their front yard by seven-thirty, and by eight people started coming out. Folding chairs and coolers and brisket that had been smoking since four in the morning, which meant running the smoker through the worst of the pricing tiers. When someone mentioned that, the guy said it was Juneteenth and his brisket didn't answer to CPS Energy.
My mother had come out and sat in the lawn chair I brought for her, the one with the extra cushion. She'd stayed until nine-thirty. My son had been down the street with his friends. I'd had two beers and talked to a neighbor about her mother, who was eighty-four and lived alone on Callaghan and whose AC had gone out twice in June already. She was trying to get her to move in. Her mother wouldn't.
I hadn't checked the app once the whole cookout. Three hours without looking at it. I'd noticed that later, lying in bed, and it felt like something I couldn't quite name. Close to relief. Or what not calculating used to feel like.
At 7:52 I checked on my mother again. She was asleep. The tablet had slipped onto the bed beside her. The water glass was half empty, which was better than nothing. I put my hand on her forearm and it was warm but not hot. I refilled the glass in the bathroom and set it back on the nightstand.
The room smelled like her lotion and the cold-air smell of the window unit, metallic and damp. I stood there for a minute watching her breathe. Her chest rose and fell evenly.
She was fine. She was probably fine.
I pulled the door mostly closed and went back to the living room.
My son was sitting up now, earbuds out.
"Is Grandma okay?"
"She's sleeping."
"It's hot in here."
It was the first time he'd said it in weeks. I looked at him. He was sitting with his elbows on his knees, his T-shirt dark at the collar.
"I know," I said. "Eight more minutes and it drops to Tier Two. I'll bump the system down."
"Okay."
He put his earbuds back in.
I sat down in the chair by the window and watched the app. Seven minutes. The house was eighty-four now. The attic was still pushing heat down through the ceiling. I could feel it if I stood directly under the hallway light, a warmth that had nothing to do with the bulb.
At eight the app went yellow. Twenty-two cents. I set the thermostat to seventy-eight and the compressor kicked on hard. I stood in the hallway and waited to feel the air change. It took a few minutes. The vents started pushing air that was cool enough to notice. Different from what had been circulating all evening.
My son didn't say anything but I saw him shift on the couch, settle back. A small thing.
At nine-fifteen I did the math. If I ran the main AC at Tier Two until eleven, that was roughly a dollar seventy-six an hour. Three-fifty to cool the house for two hours. Then at eleven, Tier One, and I could run it cheaper through the night.
Or I could set the thermostat back up to eighty-two, let the house hold what it had gained, save the money, and drop it hard at eleven when the rate cut in half. My mother's room had its own system. The window unit would run regardless. She was the priority.
She was always the priority.
The question was my son. And me. Whether we sat in eighty-two for two more hours or spent three-fifty to be a little more comfortable. Three-fifty that was also tomorrow's cantaloupe, or part of the water bill, or a few cents closer to the window unit repair fund because the Friedrich was nine years old and wouldn't last forever.
I left the thermostat at seventy-eight.
The house across the street was dark. It had been dark since April. The street was quieter than it used to be. Still lived in. Just quieter.
At ten I checked on my mother. Still sleeping. Still breathing evenly. I refilled her water glass and set it where she could reach it. Then I noticed the Friedrich's thermostat. I'd set it to seventy-six before she went to bed. She'd turned it up to seventy-eight.
I stood there looking at the dial. She'd done this before. Twice last week I'd found it nudged up a degree or two. She never mentioned it. I never asked. I didn't know if she was warm enough at seventy-eight or if she'd done the math herself, figured what her room was costing the rest of the house, and decided to carry that quietly.
I turned it back down to seventy-six. She didn't stir.
Her forearms were dry. Her face was dry. I watched her breathe for a minute and then pulled the door mostly closed.
My son had gone to his room. His door was closed. I could see the light under it, the blue flicker of his phone.
I sat in the chair and watched the app count down to eleven. The house was at seventy-nine. Better. My mother's room was holding at seventy-seven. The battery was at sixty-six percent.
At eleven the app went green. Eleven cents. I set the thermostat to seventy-six and the compressor came on and this time I could feel the difference faster, the system finally working the way it was supposed to, pulling heat out of the walls and the ceiling and the furniture that had been soaking it up all day.
I stood in the hallway between my mother's door and my son's door. Cool air from her room leaked through the crack. The main system pushed through the vent above me. For a few minutes I just stood there, between the two kinds of cold air, and it was the best I'd felt all day.
I set my alarm for three. I'd get up and check her skin, check her water, make sure the unit was still running. I'd been doing this every night since May. I'd do it until September. Maybe October, the way the falls had been going.
I figured seventy-six was what I could give them tonight. In the morning the whole thing would start over, and I'd do the math again, and I'd stand in the hallway again, and that was probably going to be enough. It would have to be.
- The body stops warning: Older adults store 1.3 to 1.8 times more body heat than younger people under the same conditions, and their perception of that heat dims with age and common medications.
- Lost hours, measured: A peer-reviewed study found that senior citizens in the U.S. now lose roughly 270 hours per year to heat-related activity limitations, a figure that rises sharply in the southern states.
- The grid's shifting peak: ERCOT's greatest-risk hour has been creeping toward 9 PM as solar generation drops off while cooling demand holds, and the grid is forecasting a record 92,200 MW peak load this summer.
- CPS already controls thermostats: Roughly 150,000 San Antonio households are enrolled in CPS Energy's demand-response program, which cycles compressors during conservation events running from 1 PM to 10 PM on peak days.