As a Washington, D.C. heat wave is forecast to push temperatures above 100°F next week, experts say the thermostat advice most Americans receive can collide with reality: many households can’t afford to cool their homes to recommended levels. Data show most pe
When the Washington, D.C. forecast turns brutal—temperatures above 100°F expected next week—many families will reach for the same knob: the thermostat.
The question sounds simple: what temperature should you choose? But the guidance that circulates from federal agencies and energy experts can feel out of reach when cooling is a line item you can’t flex, or when air conditioning isn’t there at all.
The Department of Energy’s most recent guidance suggests starting at 75 to 78 degrees Fahrenheit and increasing the setting when nobody is home. The agency also recommends using a programmable thermostat and setting it “as high as comfortable” to maximize savings on utility bills. For millions facing a dangerous stretch of heat. that advice runs into a hard contradiction: studies and surveys show how Americans actually live—and how often they wait until conditions are already far worse.
On average. Americans keep their thermostats set to about 71 degrees Fahrenheit during the day and night. according to a national Consumer Reports survey. Regional differences are small but telling: Americans in the South report setting their thermostat to 72 degrees Fahrenheit during the day. while those in the Northeast report 70 degrees.
Central air conditioning households show another edge of the gap. Not a single respondent with central air indicated they would set the temperature above 76 degrees Fahrenheit during summer.
The pattern holds in broader utility data as well. Researchers found average daytime thermostat settings were 72.1 degrees Fahrenheit in the summer, using data from the U.S. Energy Information Administration’s Residential Energy Consumption Survey, which covers more than 123 million households nationwide.
Energy savings can come with a human cost, especially when “comfort” and “affordability” don’t overlap.
Destenie Nock. a professor of civil and environmental engineering at Carnegie Mellon University. said low-income households often wait until it’s 8 degrees hotter out to even start using air conditioning. For some families. the decision is driven more by cost than by comfort—and Nock pointed to findings from heat-associated deaths in Arizona to show how that delay can turn fatal.
Nock cited that many who died had air conditioning, but it was disconnected or turned off.
The stakes are stark. More than 700 people across the United States die from extreme heat every year. according to the Centers for Disease Control and Prevention. The World Health Organization recommends 76 degrees as a safe indoor temperature. and suggests using a combination of air conditioning and an electric fan to minimize costs.
That’s where the next layer of the problem shows up: not every household can follow even the most practical version of “cool smart.”
High-tech thermostats can automate energy-saving features—such as warming a home while people are away. But many families do not have access to HVAC systems, and some live in buildings where insulation limits how effective thermostat adjustments can be.
There are also households without air conditioning altogether. Data analyzed by UC Berkeley professor Lucas Davis estimates there are about 14 million households with no air conditioning.
During heat waves, foregoing air conditioning isn’t just uncomfortable—it can be deadly. Young children, older adults, and people with chronic medical conditions are most at risk. In 2025, 31 children died in hot cars, according to the National Weather Service.
For Nock, the key issue is the mismatch between policy language and what people experience when bills arrive.
“Normally, people only choose to not use (AC) when they don’t have the money,” Nock said. “If people have the money, they choose to use it. Highlighting the cost of using air conditioners is important, because people just really underestimate the heat.”
That gap—between a thermostat set at a number designed for efficiency and the everyday reality of limited budgets and limited options—can be the difference between staying safe and slipping into danger when the weather turns.
Washington DC heat wave air conditioning bills thermostat settings Department of Energy 75 78 degrees Consumer Reports thermostat survey energy efficiency heat-associated deaths CDC extreme heat World Health Organization 76 degrees programmable thermostat low-income households AC use 14 million households no air conditioning