How to Replace a Thermostat: Some Pointers from Brookhaven

There are a lot of common household tasks that do-it-yourselfers can handle beyond changing light bulbs or replacing a fuse in their Brookhaven home. One of those is changing out a thermostat. The reasons for replacing a thermostat can vary from making an upgrade to changing out a thermostat that is not working right – or at all. Whatever the reason, the task is pretty simple and require s very little time and very few tools.

Let’s set the stage.

The materials you will need are the replacement thermostat, wire connectors, electrical tape (optional), needle nose pliers, and a screwdriver.

Here are the steps:

  1. Turn off electrical power to the existing thermostat. You can do this by flipping a breaker switch or removing a fuse from your home’s electrical panel. This would be a good time to make a note of the circuit’s location, writing the circuit number on the panel door or using a sticker.
  2. Remove the cover from the existing unit. You should be able to locate the screws that hold it to the wall mounting plate. Remove the screws and pull the unit away from the wall and mounting plate. Be careful not to touch the electrical wires together on the thermostat.
  3. Disconnect the wiring. Carefully remove the electrical wiring from the unit and keep the wires apart. You might want to tape the bare ends and also ensure that the wires don’t fall back through the wall. If the wires are not color coded, mark each one and which terminal they were removed from. Remove the mounting plate.
  4. If you are using a new mounting plate, make sure it fits over the existing hole and then pull the wires through the opening of the plate. Make sure the mounting plate is secured to the wall with the proper screws.
  5. Now match the wires to the terminals on the new thermostat. The wires are usually color-coded but if not, make sure you attach the right wires to the corresponding numbered terminals on the next thermostat. A green wire, which operates the furnace fan blower, is connected to the “G” terminal. The white wire operates the heater and attaches to the “W” terminal. The yellow wire operates the air conditioner and connects to the “Y” terminal. Use a wire nut to secure the wires and keep them apart from other wires. Ignore any other wires coming out of the wall as they are not necessary and may have been added by the original builder for other purposes.
  6. Carefully move the wires back into the wall as you line up the new thermostat on the mounting bracket. Install the new bracket and secure the thermostat to the bracket.
  7. Turn your power back on and check your thermostat by setting the temperature high or low, to engage the furnace or air conditioner.

This simple procedure can be done in less than 10 minutes. But if you have any doubts and want greater peace of mind, call a professional heating and cooling contractor to perform the installation.