Do it yourself: how to replace or install a new home thermostat

How to install a new thermostat.

Photo Credit: Nicola Stratford
By Matthew Thompson

A thermostat keeps a building or room at a specific temperature. A faulty thermostat will cause a variance in temperatures and a waste of energy. The wasted energy will ultimately result in higher utility bills and a dwindling bank account. It is a good idea to replace a faulty thermostat as soon as you discover the problem. Replacing a thermostat is a simple and a quick job for the do-it-yourself person.

The first thing to do is buy a replacement thermostat from your local hardware store. Remember to take your old model thermostat with you, or write down the information from the old one, to make sure the new one is compatible with your heating/cooling system.

Low-voltage thermostats generally will control the heating and cooling for the entire house from one location. It will operate off of a transformer that takes a 120-volt current and diminishes it to about 24-volts. If your old thermostat was not programmable it is a good idea to replace it with one that you can program. Programmable thermostats can save you around 35 percent in energy costs in some parts of the country. They are worth the investment and simple to operate.

Disconnect the power source to the heating or cooling system at the main, and if the thermostat has a cover plate you should now remove it. Next we will need to remove the body of the thermostat. Simply unscrew the mounting screws and pull away the thermostat body. Using tape that you can write on, label the wires and mark their screw terminal location. Loosen the screws and remove the wires. Take out the mounting screws and remove the base.

Take the new thermostat and thread the wires through the base, and then mount the new base to the wall. Using the instructions that came with the new thermostat, connect the wires as directed to the screw terminals. See if you can locate the low-voltage transformer that powers the thermostat. It should be located near the heating or air-conditioning unit or look for an access panel that could house the unit. Make sure all the wires are tightened to the screws and inspect for wear and tear. Your programmable thermostat will need batteries put in at this time. Mount the thermostat to the base and you are down. Read through the manufacturers instructions to learn how to program your new thermostat. The great thing about programmable thermostats is that you can program them and forget they are there. The program will run your heating or cooling system 24 hours a day. Sometimes when the power goes out they may need to be reset. Follow the manufacturers instruction on what to do during a power outage.

The cost savings of a programmable thermostat comes from taking human error out of the control of the heating/cooling system. Too many times we forget to turn down the thermostat when we go to bed at night or leave for work during the day. Having a programmable thermostat will take eliminate the need for you to manually control your heating/cooling system.