The Ecobee SmartThermostat family (including SmartThermostat Premium, Enhanced, and ecobee3 lite) operates on 24VAC low-voltage residential HVAC systems. Unlike traditional battery-operated thermostats, Ecobee requires continuous 24VAC power via a dedicated C (Common) wire or the included Power Extender Kit (PEK) adapter.
Standard 5-Wire Setup
Direct terminal connection where a dedicated C-wire exists in the wall bundle to power the thermostat display continuously.
4-Wire PEK Installation
Installs inside the furnace blower cabinet to multiplex G and Y lines, providing continuous 24VAC return without pulling new wire.
SmartSensors (Occupancy)
Remote room probes detecting temperature and occupancy to balance hotspot and cold draft room averages.
Step-by-Step Installation & Wiring Guide
- Cut Circuit Power: Switch off the breaker supplying your furnace/air handler and A/C unit before touching any wires.
- Label Existing Wires: Take a photo of your old thermostat base and apply the provided Ecobee wire labels.
- Mount the Backplate: Use the integrated level on the Ecobee baseplate to secure it to the wall.
- Insert Wires into Push Terminals: Press the terminal release lever and insert the bare copper wire into its matching port. Always insert single power wires into Rc (not Rh).
- Attach Display Faceplate: Push the Ecobee unit straight into the baseplate until it clicks flush against the wall.