Thermostats were all ugly rectangular boxes until Honeywell introduced its circular T-86 model in 1953. These days you might be more likely to associate that iconic shape with the Nest Learning ...

One morning last fall, Pat Tessier, a marketing director at the electronics giant Honeywell, stopped by my house to show me the company’s high-end thermostat, the Prestige HD. It was an unusual visit.

If you have a thermostat made by Honeywell, utility companies are about to have a lot more access to the temperature in your home -- but only if you want them to. A software update Honeywell is ...