How to Install a Programmable Thermostat

Many furnace and air-conditioner thermostats are programmable in increments of 15 minutes, allowing you to be very precise about how much energy you use. Here's how to remove your old thermostat and install a new one:
Materials and Tools:
one or two standard screwdrivers
drill and drill bit
level
safety glasses
Note: Most older thermostats contain mercury and should be recycled if possible. Check with a recycling company or a local heating and cooling company to find out where to take your old thermostat.
Steps:
Remove the old thermostat
- Disconnect the power.
- Remove the thermostat cover.
- Locate the wires from the furnace and remove them.
- Label each wire with the labels supplied with the new thermostat.
- Remove the body of the thermostat.
- Spread the wires to keep them from falling behind the wall.
Install the new thermostat
- Remove the base from the new thermostat.
- Place the base on the wall where the previous thermostat was located. Use a level to make sure the base is as straight as possible.
- Mark the wall through the mounting holes on the base.
- Remove the base. Using marks for reference, drill holes for mounting. Be sure the drill bit is thinner than the screws you'll be using.
- Fill the hole around the wires with a piece of paper towel. This prevents drafts, which could affect the performance of the thermostat.
- Feed the wires through the base of the thermostat and screw it into position. If you're mounting the thermostat onto drywall, use the drywall anchors that came with the new thermostat kit.
- Attach the labeled wires to the corresponding terminals on the base. Be sure to follow wiring instructions carefully. Color codes may not apply.
- Attach the thermostat to the base.