Replacing your thermostat is a seriously easy project with just a little know-how and common sense. Start to finish it took us about 15 minutes. For years, we had one of those old manual dial-style thermostats. It was driving me nuts! I was needing to remember to adjust the temperature up and down each day. Ergh. I don’t do well with extra things to remember for no good reason.
Especially not when new automatic (automagical?) thermostats are SUPER CHEAP. I spent $30 total and it was a middle range one with four adjustable settings. You can go really high tech (think controlling it with your smart phone) or even lower tech (only two settings), but it’s still not a giant investment when it can save you money on your energy bills and save you time and hassle. TOTALLY WORTH IT.
I bought a new thermostat for our house a while ago. I read the instructions and then never did anything with it. Cue my dad coming for a visit and asking for some projects to do. I remembered I had this little gem just sitting waiting to be installed. And so he and I did it together. Now my caution here is that this is not a project you should take on if you aren’t comfortable dealing with wiring (electricity can be a bad thing in the wrong hands.)
Find a knowledgeable friend or better yet, hire a professional. We have a simple single stage heat and cool system (not a heat pump) so ours was very straight forward to install. You’ll need to know what type your system is (single stage heat and cool, heat pump, multi-stage, heat only or cool only) before you get started to make sure the thermostat you purchase will work with your system. Read the manufacturer’s instructions – THEY ARE INVALUABLE.
Okay – disclaimer over. You still with me? Awesome – let’s get started!
What You’ll Need
- New thermostat (with installation instructions)
- Drill (to create new holes for wallplate, but you might be able to use the existing holes)
- Fine grit sandpaper
Step 1 – TURN OFF POWER TO HEATING/COOLING SYSTEM
TURN OFF THE POWER TO YOUR HEATING/COOLING SYSTEM! I mean at the breaker. Find your breaker box and flip the switch off. It’s easy.
Step 2 – Remove Existing Thermostat’s Faceplate (Both Parts)
Okay, you’re safely powered down. Next up is to remove the faceplate of the old thermostat so you can get at the screws underneath it that are holding the wallplate in place. This old style dial one actually has two faceplate sort of things. The first one just sort of popped up from the bottom. In the picture you can see what’s underneath the faceplate (the arrow is pointing to the old sealed tube that contains mercury which means I have to dispose of it in a special way – the installation instructions for your new thermostat will tell you how).
Also notice that you can begin to see the wires underneath…but not too much yet.
Next up is taking your screwdriver and removing the four screws that are holding faceplate #2 in place (see my arrows?) Your old thermostat may or may not look like mine, but you get the drift. You’ll need to remove all the faceplate parts in order to gain access to the wallplate (and wires) behind it.
Step 3 – Disconnect Wires (and Label Them If Necessary)
Now you should be looking at the wallplate with wires still attached. First thing is to make sure you see if the wires match the letter screw they are under. In the picture below you can see that mine are actually the right colors (wire matches color indicated by letter shown – Red wire is attached ‘RC’ with no duplicates) so I didn’t bother to label them. If not, make sure you use the handy little sticky labels that came with your new thermostat to accurately label each wire as you disconnect them. For example, if you have a white wire connected to the terminal marked ‘G’ – then please label the white wire with a ‘G’ label.
Step 4 – Remove Wallplate from Wall
Step 5 – Mount the New Wallplate
It’s time to get to the good stuff! We need to install the new wallplate. Now because my old thermostat was so old, there was no way the holes from the previous wallplate would line up with the new one, but hey – maybe you’re luckier than me. I needed to drill two new holes (and because my walls are pretty soft, I went ahead and installed anchors at the same time.
Simply hold your new wallplate up to the hole with the wires, pull the wires through and pencil in the new holes that need to be drilled. We also used a level to make sure it was nice and even. Remove the wallplate, drill your new holes, and put the wallplate back up there. Install the screws and use a level to make sure they’re nice and even (there’s a little bit of give to help you straighten it out.)
Step 6 – Reconnect the Wires
Let’s reconnect those wires! First step is to make sure the wires are nice and clean. My dad recommends sanding the bare wire lightly with fine grit sandpaper to make sure you get the best connection.
Then you simply insert the matching wire into the right spot and tighten the screw carefully to get a nice secure connection. Make sure you put the right wire into the right connection. Notice my ‘G’ connection has my green wire (remember that was my ‘G’ connection from my old thermostat?)
Step 7 – Install the Batteries in the Faceplate and Set Fan Operation Switch
The new thermostat I bought requires two AAA batteries so I needed to install those before I attached the faceplate to the wallplate.
I also needed to make sure the switch “Gas or Oil” or “Electric or Heat Pump” was set correctly. Our system is natural gas for heat so we left the switch at the “Gas or Oil” side.
Step 8 – Install Faceplate and Turn on Power
Only thing left to do is to put the faceplate on the wallplate. You can feel when you get the faceplate on correctly because the contacts on the faceplate push into the contacts on the wallplate.
Now turn the power back on.
You did it!
Only thing left to do at this point is to follow the manufacturer’s instructions on how to properly set up your system – i.e. setting the time and temperatures you want. I’m presently experimenting, but I have a four stage system, but I really only need two stages right now (I’m home during the day) so I set up “twin” stages. I have two stages set for the same temperature each day. My ‘wake’ and ‘leave’ are the same temp and my ‘return’ and ‘sleep’ are the same.
Make sure you save your operating manual in case you ever need to change something about your setup.