During setup, your Google Nest thermostat senses what wires are connected and asks you a few questions so it can offer different features specifically for your heating or cooling system.
Most thermostats are designed for conventional forced air systems, so they treat every system the same, even though modern high efficiency heating and cooling systems work differently. A high efficiency system simply won't be as efficient or comfortable if it's treated like a conventional system.
System Match changes the Nest thermostat's learning algorithms and activates different features depending on what kind of system you have to help reduce wear on your system and improve temperature accuracy. These features, including Early-On, Heat Pump Balance, True Radiant and Filter Reminders, are designed to make your heating or cooling system work better so you can save energy and stay more comfortable.
How System Match knows your system
When you first install your Nest thermostat, it checks to see what wires you've inserted into the base's connectors. It figures out most of the information it needs for System Match simply by looking at your system's wires.
Your thermostat will also ask you a few questions during setup, like whether your system is forced air (blows air out of vents) or if it's dual fuel (uses more than one fuel type). Your answers will also help System Match automatically switch on the right features for your home.
Types of System Match features
System Match enables different features for forced air, heat pumps with auxiliary heat, and radiant systems
For forced-air systems:
Filter Reminders: If your system blows air out of vents, then it has a filter that could get clogged. A dirty filter could cost you more on your heating and cooling bills. The Nest thermostat keeps track of how long your system has been on and sends you timely Filter Reminders to let you know when to change your filter.
Early-On: Early-On is designed to keep you more comfortable by getting you the temperature you want when you want it. So if your schedule says 64ºF at 7am, Early-On might turn on the heat at 6am to ensure your home is at 64ºF when your alarm rings at 7am. Early-On is available for forced air systems. If you have a heat pump with auxiliary heat, the Nest thermostat will only use Early-On for cooling and will activate Heat Pump Balance for heating.
For heat pump systems with auxiliary heat:
Heat Pump Balance: If your system has a heat pump and a high-energy auxiliary heat strip (and you have a Wi-Fi connection), the Nest thermostat will activate Heat Pump Balance for heating. Heat Pump Balance minimizes how often expensive auxiliary heat comes on to save you energy and keep you comfortable.
Early-On: Heat Pump Balance only works for heating, so heat pumps with auxiliary heat will have the option to use Early-On for cooling. Early-On will also be the only available option if your Nest thermostat isn't connected to Wi-Fi.
For radiant systems:
True Radiant: True Radiant gives underfloor radiant systems and radiator systems a predictable schedule with even heat. It is only available for these systems, which use water or electric coils to heat the home, rather than blowing hot air out of vents.