How to Replace Analog Thermostat with Digital?

Substituting your analog thermostat with a digital one is an excellent way to save on your heating bill because digital thermostats can control the temperature in your home more accurately. New digital thermostats can save you up to 15% money on your heating bills. I think that’s more than enough reason why you should do it as soon as possible. My most current little project was replacing the analog thermostat with a digital one. I will tell you step by step how I did it.
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How to Replace the Analog Thermostat with a Digital?
So How to Replace Analog Thermostat With Digital? In short, to replace the analog thermostat with a digital one, you’ll first need to turn off the power in the house, remove the faceplate from the current thermostat, label the wires, detach the wires and remove the cover, mount the new thermostat, rewire it, and attach the faceplate.
Ensure you read the instructions for your new thermostat thoroughly before you start with the work because it is very important every time you are operating with electricity. Therefore, turn off the power to your heating and cooling system! You can do this by either going to the fuse box or circuit breaker or if a light switch regulates your thermostat. Just ensure that the switch is switched off.
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After turning off the breaker box’s power, you should always, always, ALWAYS, confirm the power is shut off with a voltage tester and/multimeter. NEVER assume the power is off. A line voltage of 240 can kill you.
Remove the faceplate and detach the wires. Since some thermostats comprise mercury, your old thermostat will need to be recycled. You can look on Google to see where you can recycle it. Twist the back part of the thermostat onto the wall (after drawing the wires through space). Look at your directions and check the diagram to recognize which wires get connected where. After wires are attached, you can connect the digital thermostat. Depending on the type of your new thermostat, the number of batteries will differ. Finally, connect the base and screw in position. Switch the power back on, and you’re finished!
To see the detailed principle of How Does an Analog Thermostat Work, read this article.
Why Analog Thermostat Is Bad?

Analog Thermostats are not accurate and can deviate by a few degrees from the set temperature resulting in an additional energy cost and with a larger bill. Therefore, it is desirable to replace them with digital ones.
Some people are used to their old thermostats, that they have been using them so many times during the years. At that same time, you were worried about how much the energy bill will be, unknowing the analog thermostat you have was wasting more money and energy than it should.
This extra expense, particularly in the winter months, was caused by the analog thermostat, which didn’t hold the close temperature span you desired. Therefore, you raised and lowered the thermostat setting as much as four or five degrees each time to meet your needs.
When you raised the setting on your analog thermostat for more than two degrees, you could not get the desired temperature, rather the temperature went higher than you set it. Digital thermostats have more accurate temperature sensitivity providing your place with greater comfort with less costly utility bills. These thermostats come as either programmable or non-programmable – your decision.
Therefore, the digital thermostat is a must-have in every house. Save cash, preserve energy, go green.
Replace Analog Thermostat With Digital – Step by Step
The process of replacing an analog thermostat with a digital one consists of 9 simple steps that we will explain here in detail. So let’s start!
Step 1: Carefully Choose New Thermostat

Before installing a new thermostat, you must check your home’s compatibility. Houses are wired in two ways, line voltage and low voltage, and you’ll want to buy a thermostat that will operate with your particular heating and cooling system. Therefore, choosing the right digital thermostats is important.
Step 2: Turn Off Power to The Furnace

Crucial: Switch off all power to the heating and cooling system before performing any electrical work to bypass any chance of electrocution or injury. HVAC systems are powered down at the breaker box.
The power for some furnaces can be found directly on the boiler, generally with a toggle switch.
It is also a great practice to switch your current analog stat all the way down prior to detaching.
Step 3: Remove the Cover From the Current Thermostat

With the wires opened, you will be ready to test the wires with a circuit tester to confirm that the power is off. See the type and number of wires to discover your thermostat’s compatibility. Line thermostats will be with two thick wires, while a low voltage stat will be with anywhere from two to eight small-gauge wires.
Warning: Many older analog thermostats hold a glass tube of mercury. Mercury is regarded as a hazardous material and needs to be disposed of correctly.
Step 4: Mark the Wires

You will want to mark the wires. Take a photo of, or note where the wires are connected before detaching them. This is very important! If you connect the wire incorrectly, the thermostat will not work.
Note: They are not always color-coded or identical for each thermostat. For example, if the green wire fits the G terminal, the corresponding wire must be inserted into the new stat terminal.
Step 5: Detach the Wires and Remove the Wall Cover

You must unscrew each wire from the terminal and also unscrew the wall mount as well. The wall mount will usually have one screw on each side. Examine to see if the current drywall fasteners follow with the new thermostat wall mount. If they don’t, you must connect the drywall anchors in the proper location.
Note: I suggest that you secure the loose wires, using a tape, so they don’t retreat into the hole.
Step 6: Mount the New Thermostat

The new thermostat must line up and match with the current holes. If it does not match, you must drill new ones. Install the new thermostat flush with the wall and label the holes on the wall with a pen or marker. Make sure to use a level to be sure the mounting isn’t twisted. Look for the marked places on the wall and drill into it.
Note: The drill bit must be smaller than the screws equipped with the new thermostat. If needed, insert the drywall fasteners. After you drilled the holes, screw the new stat’s wall cover onto the wall.
Feed the wires into the hole in the thermostat’s rear, and you will be able to rewire the new thermostat.
Step 7: Rewiring

Now you are ready to start attaching each wire to the proper terminal. Refer to the photo or notes you took to make sure the right wire is connected. In some instances, you will have an additional wire that you don’t need.
The extra wires are the wires that were not attached to the old thermostat. This is fine, and you do not have to bother with the exposed wires.
Step 8: Connect the Faceplate

Today, most digital thermostats need batteries so they can operate properly. Insert the right batteries that fit, then close the faceplate onto the front of the new thermostat. Consult with the user handbook if you run into some problems connecting the faceplate.
Step 9: Test the New Thermostat

Once you have completed all the previous steps, and you have attached your new digital thermostat, it is time to verify that the installation was done correctly. Turn on the power to the HVAC system. Switch the heating and air system back on and test the thermostat. To do this, just switch it so that the temperature is higher or lower than the current.
For example, if the current temperature in the room is 69°F, you might want to shift it down to 66°F. Within a few seconds, you should hear the HVAC system’s fan heat up. If nothing occurs, turn off the power to the system and test the wiring.
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Why Is Your Analog Thermostat Not Getting Power?
If the thermostat operates from the home’s electrical system, review the circuit breakers. One of them might have fallen and cut off the power of the stat. Restart the breaker. If this doesn’t do it, then the thermostat problem could come from detached connections or different wiring issues.
How Do You Know if You Need to Replace Thermostat?
Four clues your thermostat is bad
- Clue #1: Your thermostat has no power or is unresponsive.
- Clue #2: Your heater or A/C won’t switch ON.
- Clue #3: Your A/C or heater works continuously and won’t switch OFF.
- Clue #4: Home temperature and setting are not equal.
Assume you have other cooling system maintenance completed, such as substituting the coolant and radiator hoses that have been in service for numerous years. In that case, it could be a great idea to replace the stat simultaneously for peace of mind.
How To Know If Your Digital Thermostat is Broken?
The most obvious indications of a broken thermostat are:
- The stat display is off or is non-responsive.
- Switching on the heat or AC does nothing.
- The heat or AC will turn on but either stays on nonstop or cuts out prior to the temperature setting is how you want it.
Can Thermostat Wires Shock You?
They will not commonly shock due to the low voltage, except you have your fingers over the thermostat contacts when the relay circuit is opened. There are direct stats, like for electric heating, which works 110/225 VAC. The wires to those will be home-style wiring.
Final Thoughts
Analog thermostats are cheap but in a long-term they cost you a lot of money. Therefore, it is advisable to replace them with digital or smart thermostats which have a lot of advantages. What you need to pay attention on is to BE SURE to turn off the electricity in your house during the replacement process so that something does not go wrong. I hope that with these instructions you will successfully replace your old analog thermostat and enjoy with the new one.