If your 3rd-gen Google Nest Thermostat is controlling a hot water tank, your thermostat can automatically help you save energy by stopping domestic hot water production when you’re not at home.
When you leave home, Home/Away Assist will notice that you’re away and switch to the Eco Temperature. Your heating won’t turn on (unless the ambient temperature drops below the Eco Temperature), but your hot water system will continue to run according to its schedule.
After you’ve been away for more than 48 continuous hours, your thermostat will automatically turn off your hot water and ignore your hot water schedule. However, your hot water will be turned on for a short time every couple of days to help prevent the formation of bacteria, such as Legionella.
How the Nest Thermostat helps prevent Legionella bacteria
You’ll save energy without sacrificing comfort, and you don’t have to worry about turning off your hot water or even adjusting your hot water schedule. When you come back home, your thermostat will automatically resume both your central heating and domestic hot water on their normal schedules.
If you get back when your hot water isn’t scheduled to be on, you can boost it to get your hot water ready for you straight away. Just tap the Hot water icon on the Nest app home screen. You can also boost hot water with the thermostat. See the following article for more details.
Change Nest thermostat domestic hot water settings
Keep hot water schedule while you’re away
If you want to keep your hot water schedule on while you’re away, you can disable the Home/Away Assist hot water setting.
Nest thermostat domestic hot water settings