With their ability to monitor and adjust temperature, humidity and the presence of electricity they may be the last best hope for evacuated homeowners.

FOUR BRANDS of so-called smart thermostats now dominate the U.S.: Ecobee, Honeywell, Emerson Sensi, and Nest. The degree of market penetration varies by region, but more importantly—as our Cognition database research has shown, the level of adoption is strongly affected by price and utility-driven rebates (if any). In states without rebates or energy efficiency incentives, adoption tends to lag.