How to Install a Programmable Thermostat

By Staff

I’ve always wanted to install a programmable thermostat, but have been a little intimidated by the thought of any DIY project that involves wires.  What can I say, I’m a chicken when it comes to anything electrical, and usually resort to searching Angie’s List for a reputable electrician.  After reading a few “How-to” articles online I summoned the courage to check out a few models of thermostats.  I found that like most everything electronic, there is a range of options to choose from ultra-cheap to over-the-top expensive.

Our old, original thermostat

We settled on a medium-grade model, not the cheapest, but not the most expensive, either. It was a 5-1-1 GE Honeywell programmable thermostat (the 5-1-1 means you can set a weekday schedule and a Saturday/Sunday schedule, independently).  This feature appealed to us because our weekday schedule varies from our weekend schedule, as I suspect is true in most households.  With new thermostat in hand, I’m ready to tackle the installation.

Disclaimer:  The following instructions are for inspirational purposes only, and are not meant to substitute manufacturer instructions that come with your particular model.

Step 1 – Turn off all power at main electrical panel.   Some instructions I found online advised to simply turn off power to the room your were working, others suggested throwing the main switch.  I always lean towards safety and decided to turn everything I could find on the electrical panel to the “Off” position.

Our old thermostat, minus cover and control board

Step 2 –  Remove cover and control panel from old thermostat.  The cover and control board on most models snap off–look for a recessed lip around the sides or bottom of the original thermostat where you can grab and remove the faceplate and control board.  Take care setting this aside as you may have to reinstall if something goes wrong further in the installation.

Step 3 – Label wires according to their current position, and remove them one by one.  Most new models of programmable thermostats come with sticker labels that you can use to wrap around the wires coming from the wall.  If your package doesn’t contain pre-printed labels you can substitute with masking tape and a Sharpie.

Step 4- Remove old thermostat plate from the wall.  Be sure not to let the mess of wires drop back into the wall when unscrewing the old plate.  Some instructions recommend taping a group of wires to the wall, but I found that the wires were so stiff that simply spreading them out a bit adequately prevented them from dropping back into the hole in the drywall.

It’s a good idea to use a level–I did when drilling, but not when taking the photos!

Step 5 – Attach new thermostat plate to the wall.  Most of the time a new model’s plate will not match up to the existing holes from the old thermostat.  This was the case with our model.  I simply drilled a couple holes for the new thermostat, and inserted the drywall anchors that came in the new packaging (don’t worry, the instructions accounted for this by indicating the drill bit size to use, etc.).  Go ahead and insert batteries if your model requires them.  Our model required two AA batteries (installed just above the wire connections) to hold the programming settings in the event of a power outage.

Step 6 – Reattach the wires according to their label and the corresponding spot on the new thermostat.   This was the most difficult part of the entire project because there wasn’t much room to work with, and depending on your heating/air conditioning system you could have several wires to attach.  We finally managed to get them all attached and were ready for the final installation step.

Step 7 – Attach control panel and face plate for new thermostat*.  This step reminded me of attaching an old parallel printer to a computer–simply match up the pins on the control panel with the pins on the back plate attached to the wall.

*Hint:  Make a handwritten note of the wires you attached (C, G, Y, R, etc.) before covering with the new control panel and face plate.  You’ll need to know this to properly program your new thermostat based on the type of system your have.  I didn’t know this ahead of time, and had to remove the faceplate to remember the letter designations I had attached.

You can see it got a little warm in the house with the power off!

Step 9 – Turn power back on and program new thermostat according to manufacturer instructions. We ran through the programming setting for weekdays, and then Saturday and Sunday.  In the summer time we let the temp get a little higher at night and sleep with ceiling fans running.  Before we wake up the thermostat is programmed to cool things down for getting ready for work and school, and then returns to a higher temperature for the day.  In the winter, we’ll reverse this process by letting things cool down after we are tucked away in bed, and warm things up during the early morning hours.

I haven’t received my power bill yet, so I can’t report on the savings (but I will in a future post). I imagine the long periods at night, and during the day, with increased temperatures will help reduce our power bill during these dog days of summer.

Still need help? Search Angie’s List for a recommended electrician in your area.

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