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Install a Programmable Thermostat

Install a Programmable Thermostat

Tired of heating or cooling an empty house while you're away? In about an hour, you can be on your way to a more comfortable home. Depending on the programmable thermostat you install, you can select day and night temperatures and even a setting for every day of the week. You'll be more comfortable with your heating and cooling bill, too.

Tools & Materials

Use this checklist when you go to the store and purchase your items.

Install Your Programmable Thermostat

Read the instructions with the new unit BEFORE starting the installation. Manufacturer's installation instructions might differ slightly for each model. Because of the variety of manufacturers, your heating and cooling system may not match your thermostat instructions exactly. If you have any doubt about the electrical connections, contact the manufacturer.

When working with electricity always:

  • Turn OFF electricity at the main fuse box (or the circuit breaker box) that controls the power to the fixture or the room you’re working on.
  • Test the wires to ensure the power is OFF.
  • Place the wall switch in the OFF position.
  • All electrical connections must be in agreement with local codes. Check with local authorities to see if a permit is required.
  • If in doubt, consult a qualified electrician.

Step 1

Turn off the power supply to the thermostat.

Step 2

Remove the old thermostat, including the wall plate. Older thermostats with glass tubes contain mercury. Use caution when handling and check with your local recycling company for disposal instructions.

Step 3

Label the wires on your system, noting where they were attached on the old thermostat. Ignore the wire color; use only letter designations to identify the wire types. Secure the wires (tie into a loop or tape them to the wall) to keep them from falling back into the wall.

Step 4

Install the new wall plate, if there is one. You may need to drill new holes for the new model. Use a level to mark where the holes are to be drilled. Use drywall anchors, if necessary.

Step 5

Match each labeled wire with the same letter on the new thermostat terminal, and connect them accordingly. Connect these wires as directed by the manufacturer's instructions that come with your particular unit. Follow these instructions carefully. Install batteries, if needed.

Step 6

Mount the unit to the wallplate.

Step 7

Restore power and program the new thermostat as directed.