What is involved in replacing a home thermostat?

A thermostat is a device that controls heating and cooling. Thermostats can be found in homes, cars, trucks and RV’s. Having a properly functioning thermostat will not only allow you to be comfortable, it will also save you money as your heating and air conditioning operates more efficiently. For purposes of discussing thermostat replacement, we will focus on replacing a thermostat in your home.

First, for those who do not want to go the “DIY” route, simply call a licensed electrician or HVAC contractor. It will be a simple service call.

For those who do want to go the “DIY” route, start by purchasing a replacement thermostat from your local hardware or home improvement store. Before you head to the store, it might be helpful for you to take a picture of the thermostat to be replaced and to bring your original packaging if you still have it. Most replacement thermostats will work with the unit you currently have, but there are always exceptions. Matching them up properly will save you time and effort.

Once you have purchased your replacement thermostat, you will want to read the directions thoroughly. Remove the old thermostat from its wall mount and take pictures of the existing wiring. At this point, do not touch any wires! Go to your circuit box and turn off the individual circuit breakers designated for your thermostat, your furnace and your air conditioning.

Now that the back of your old thermostat has been separated from its wall mount and now that you have pictures of the wiring, you can disconnect the wires. As you disconnect the existing wires, it is very important to write down (or label with tape) where each wire (or a particular wire color) connects to the base of the old thermostat. Some wires may have no connections, label or record those as well. Once you have disconnected all of the wires from your old thermostat, it is a good idea to tape them all together with a larger object such as a ruler so they do not disappear down the opening on the wall. Make sure the tips of each wire are shiny and will make a good connection in the new thermostat. You can scrape or sand the wire tips or make new cuts if the wires are long enough.

Your new thermostat will come within own wall mounting plate. Install it after the original plate was removed. Make sure it is level, which is especially important if your replacement thermostat has a mercury tube.

You can now wire your new thermostat to match exactly how your old thermostat was wired. Note: if the wire connection options are not clear to you, it would now be a good idea to review your notes and pictures. If still not clear, you should call an electrician or an HVAC contractor.

Once the new thermostat is wired properly, make sure you have installed batteries to your new thermostat if it came with a battery option. You can now attach the thermostat to the new wall mount. Most slide down on the wall mount from top to bottom. Go back to your circuit box and turn the power back on for the thermostat, heating and air conditioning.

Set a temperature that will activate your HVAC system (both heat & cooling separately) and each time, give your system about 5-10 minutes to activate. If there is a reset button on your new thermostat, be sure to activate it.

You should be good to go. If for some reason your thermostat is not working properly, re-read the instructions and retrace each step you took in the installation process.