Nest thermostats work with zoned boiler systems.
In zoned systems, each thermostat controls heating independently in order to heat different areas of the house. Zoned systems save energy by allowing homeowners to only heat the part of the home that they need, instead of the whole house.
In a zoned system, multiple thermostats control one heating system that selectively distributes heat different parts of the home. For example, when one zone needs heating, that zone’s valves open, guiding the hot water to the radiators or in-floor pipes in that area of the home. When both zone valves aren’t calling for heat, the boiler turns off, saving energy.
Some heating systems that are called zoned systems aren’t actually zoned systems. A typical example of this is a home with multiple thermostats that each control their own heating system for a specific part of the house. Since no zone valves are used, these systems aren’t truly zoned systems.
How to tell if you have a zoned system
There are two indications that you have a zoned system:
Your home has more than one thermostat
Your home has more than one heating system or more than one type of heating system (for example, radiators and in-floor radiant)
Nest thermostats will work with many types of heating, regardless of whether they’re zoned systems. However, Nest thermostats are not compatible with electric radiators or electric underfloor systems. See:
How Nest thermostats work with zoned systems
If you have a zoned system, each zone will need its own thermostat.
You can replace all your old thermostats with Nest thermostats, or you can replace just one to try it out.
Each Nest thermostat will need its own Heat Link, which is included in the box with Nest thermostats in Europe.
Each Heat Link will connect each zone valve, either directly or via a junction box.