Multi-Speed Fan
Systems

Installing ecobee with
Heat-only Systems 

ecobee thermostats require a C (common) wire to power on. If you only have two wires at your current thermostat, there are a few installation options available. To better understand the options you have, you'll need to look at the wires that come from the thermostat and where they connect to the furnace or boiler system.

Article: What do my thermostat wire labels mean?

Using a C Wire

If you have an extra wire available to use behind your existing thermostat and your furnace or boiler system control board has a C terminal. 

Article: Heat Only Installation (Option #1)

Article: 3-Wire Installation (R, G, W)

Using an External 24V Transformer

If your furnace or boiler control board does not have a C terminal, then you can power the thermostat by adding a 24V Transformer. 

Article: Heat Only Installation (Option #2, #3)

Using the Fast-Stat Common Maker

In most cases when you only have 2 wires  available behind your existing thermostat, you can use the Fast-Stat Common Maker to complete the installation.

Article: Fast-Stat Installation

Article: Heat Only Installation (Option #4, #5)

Installing ecobee with
Heat Pump & Dual Fuel Systems

ecobee thermostats are compatible with heat pump and dual fuel setups, provided your system uses a single O/B wire. Your system won't be compatible if it uses separate O and B wires. If you're unsure you can also check your system compatibility using the Compatibility Checker tool.

Article: What do my thermostat wire labels mean? >

Using the Power Extender Kit

If your thermostat doesn't have a C wire and there are no extra wires to use, you can use the Power Extender Kit (PEK) to complete the installation.

Article: Installing with the PEK

Using a C Wire

If you have an extra wire available and your air handler control board has a C terminal. 

Article: Installing with a C wire

Article: Installing with a Boiler and AC

Setup & Preferences

If you have a heat pump system with auxiliary heat (AUX), you'll see the AUX Savings Optimization feature under the thresholds menu. This is important for those who wish to limit the use of their AUX heat.

Article: Automatic Staging for Heat Pumps

Article: Configuring the O/B Reversing Valve

Installing ecobee with
Zoned Systems

ecobee thermostats are compatible with zoned HVAC systems. You do not need to do anything special to setup ecobee with a zoned system and you don’t need to setup a zone controller as an accessory on your ecobee. Just follow the guided setup as if you don’t have zone controllers. Note that wireless sensors don't replace the functionality of a zone system. In other words, you'll still need one thermostat connected for each zone of your HVAC system.

I have a Zone Board / Relay

ecobee thermostats are compatible with zone boards that can support independent 24VAC thermostats. Note that if you are installing using the Power Extender Kit (PEK) , it will be installed at your zone board.

Article: Zone Switching Relay (No C Terminal)

I have Hot-Water Zone Valves

ecobee thermostats are compatible with systems that use zone valves. There typically won't be enough power to support multiple smart thermostats, so you may need to add an 24V transformer and an isolation relay.

Article: 3 Wire Hot-Water Zone Valves

Article: 4 Wire Hot-Water Zone Valves

Article: Installing with a Boiler and AC

Installing ecobee with
HVAC Accessories

Most ecobee thermostats like SmartThermostat with voice control offer Accessory Support. That means you can control a humidifier, dehumidifier, or ventilator from the ACC +/-  terminals. To better understand what options you have, you'll need to take a closer look at the wire(s) that connected to your thermostat or existing accessory controller (like a humidistat). 

Installing Accessories

If you have 1 wire that goes from the accessory to your thermostat, then you have an Internally Powered accessory. If you have 2 wires that go from the accessory to your thermostat, then you have an Externally Powered accessory.

Article: 1 Wire Accessory Installations

Article: 2-Wire Accessory Installations

Setup & Preferences

The ecobee will guide you through accessory configuration during initial setup and you will be given the option of selecting a 2 wire or 1 wire accessory. Make sure to select the option that reflects your accessory's wiring as this could cause the equipment not to turn on.

Article: Configuring Your Accessory

Installing ecobee with
Multi-Speed Fan Systems

With the release of firmware versions 4.6.3 and up, many ecobee thermostats are now compatible with low-voltage multi-speed fan systems, including Fan Coil Units (FCU) and Packaged Terminal AC (PTAC) systems. If your thermostat is all ready installed, you will need to make some wiring changes and reconfigure your thermostats equipment settings.

Article: Latest Device Firmware Versions

Installing your thermostat

When wiring an ecobee thermostat for a multi-speed fan system, specific wiring terminals on the ecobee will be used to accommodate for the lack of dedicated G2/G3/S1/S2 terminals.

Article: Multi-Speed Fan Installations

Setup & Preferences

In order to configure your ecobee for multi-speed fan support, you'll need to select the "I'm a pro" option during the initial setup.

Article: Configuring Multi-Speed Fan Support