Across the U.S., it's a hot summer, and electricity prices are high. Various public officials and corporate websites suggest people set their thermostats to 78°F (25.6°C), or even 81°F (27.2°C), as a way to stay relatively cool without breaking the bank. But as someone who studies energy costs, I know from both personal and professional experience that it's not that simple.

It may be useful to start at 78 F (25.6 C) to keep a lid on costs, but that temperature is neither a safety threshold nor a temperature every household will find comfortable and…

Across the U.S., it's a hot summer, and electricity prices are high. Various public officials and corporate websites suggest people set their thermostats to 78°F (25.6°C), or even…