Google Nest thermostats are usually compatible with zoned systems that use multiple thermostats, including zoned systems with dampers. However, some zoned systems that require thermostat damper control aren’t compatible with Nest thermostats, while other zoned systems may need a C or common wire to be compatible.
If you have multiple thermostats in your home, you have a zoned system. In zoned systems, each thermostat controls heating and cooling independently in order to heat or cool different areas of the house. Thermostats in zoned systems can control the same heating and cooling system or each thermostat can control its own system.
When multiple thermostats control one system, the house is divided into zones using dampers in the ductwork throughout the house. When one zone needs heating or cooling, the damper for the ductwork in that zone opens, guiding the warm or cool air to that zone. Zoning with dampers is usually coordinated using zone relay panels.
Multiple thermostats in the same home
If you have more than one thermostat in your home, they’ll work together to try to keep you comfortable and help save energy.
You can replace one or all of your thermostats with a Nest thermostat. You don’t need to replace all of your current thermostats, they’ll keep controlling your system just like they always have.
If you only want to replace one of your current thermostats with a Nest thermostat, replace the one in your main living area, so it can better tell when you’re home, learn what temperatures you prefer, and automatically help you save energy.
Your thermostats will learn separate schedules
Nest thermostats in the same home don’t share temperature schedules. Each thermostat learns a separate schedule for the zone that it controls. So you can teach your thermostat downstairs to warm up the kitchen in time for breakfast, while the thermostat upstairs turns down for the day.
Home & Away Routines and Eco Temperatures
Your phone's location and Nest product sensor data are used to tell when your home is empty or occupied. So all of the Nest thermostats in your home can switch to Eco Temperatures when you’re away, and back to your regular temperature schedule when you return.
You can also set Eco Temperatures manually on any of your Nest thermostats to save energy in one part of your home. Your other thermostats will continue to run their normal temperature schedule to keep you comfortable.
Zoned system panels
Generally speaking, Nest thermostats are compatible with zoned system panels.But some zone relay panels don't provide the Nest thermostat with enough power to charge its internal battery. In this case, the Nest thermostat needs a common or “C” wire connected to provide power. You can contact a Nest Pro in your area to see if a common wire is needed and to estimate the cost of installing one in your home in order for your system to become compatible with a Nest thermostat.
Some zoned systems rely on the thermostat to control the opening and closing of the dampers to control the flow of air throughout the home. If you have multiple dampers controlling the flow of warm and cool air to zones in your home, your system may be compatible with the Nest thermostat as long as your system only uses standard thermostat wires.
However, some damper systems use proprietary wires that aren’t compatible with Nest thermostats. For example, if your current thermostat has wires labeled MISC or Damp, it is not compatible.If you need help determining if your damper system is compatible, contact a Nest Pro in your area.
One thermostat controls other thermostats
In some zoned systems, one thermostat controls some or all of the other thermostat's functions. For example, if the controlling thermostat isn’t already heating, the other thermostat won’t be able to turn on heating.Nest thermostats may not be compatible with this kind of type of system. Contact a Nest Pro in your area to see if your system can be made compatible with a Nest thermostat.
Zoned systems are different than multistage systems
While a zoned system will have different thermostats that control the heating and cooling for different parts of the same location, a multistage system is one zone where there is more than one level of heating or cooling. This allows households to save energy by only using the lowest level needed.
A multistage system will have multiple heating wires (such as W2 or W3) or cooling wires (Y2 or Y3). Nest thermostats are compatible with up to three stage conventional heating (systems with W1, W2, and W3) and two stage conventional cooling (systems with Y1 or Y2).