Convert ecobee to Nest
Before/After photo of a successful conversion.
A little while back, we decided to switch out our old Ecobee thermostat for a fancier Nest one. We were pumped about the upgrade, but it ended up being way trickier than we thought. It took a sharp eye and steady hands to get it right. We had to make sure every wire went exactly where it belonged on the new setup. Getting the wiring to match the Nest?s layout was no joke?it had to be spot-on for everything to work smoothly.
We?ve got a picture showing the before-and-after of the wires we switched around. This one?s from the basement, where the thermostat sits near the furnace and all its wiring. The "before" part shows how things looked with the Ecobee hooked up. The "after" part shows the new setup for the Nest. This was just the basement setup, but it?s pretty similar to what we dealt with at other Ecobee spots in the house. Each place had its own little quirks, but the main hassle of sorting out the wires was the same everywhere.
Thermostat Letters Fun Facts
The letters on a Nest Thermostat (like Y, C, W, G, R, and OB) refer to the terminals where you connect the wires from your heating and cooling system. Each one has a specific role in controlling your HVAC setup. Here's what they typically mean:
- Y: This is for the cooling system, specifically the compressor in your air conditioner or heat pump. When the thermostat calls for cool air, it sends a signal through the Y wire to turn on the cooling equipment.
- C: Known as the "common" wire, this provides a continuous 24-volt power supply to the thermostat. It's not always required, but it helps keep the thermostat powered, especially for smart features like Wi-Fi.
- W: This controls the heating system. When heat is needed, the W wire signals the furnace or other heating equipment to kick on.
- G: This operates the fan or blower. The G wire tells the fan to run, either automatically with heating/cooling or manually if you just want air circulation.
- R: This is the power wire, delivering 24 volts from your system's transformer to the thermostat. Depending on your setup, it might be split into Rh (for heating) and Rc (for cooling), but on many Nest models, there's just one R terminal that handles both.
- OB: This terminal (often written as O/B) is typically for heat pump systems. It controls the reversing valve, which switches the heat pump between heating and cooling modes. The Nest setup will ask whether it's an "O" (energized for cooling) or "B" (energized for heating) based on your system.
These meanings can vary slightly depending on your specific HVAC system (like whether you have a conventional furnace, heat pump, or dual-stage setup), so the Nest app or manual guides you to wire them correctly during installation. If you're unsure about your system, it's worth double-checking how the wires were connected on your old thermostat or consulting your HVAC manual!