Many homeowners look to save with DIY thermostat replacement. Whether this is the right move depends on the type of unit and the work involved. Installing a smart unit or even a Wi-Fi-enabled device may require adding wiring, which you’ll need an electrician for. However, installing the same type of thermostat in the same location requires just a few simple steps.
Below, we’ll examine the risks of replacing a thermostat yourself and, if you choose to do so, the basic steps to a successful installation.
Risks of DIY Thermostat Replacement
If you don’t have the proper experience, installing a thermostat incorrectly can increase the risk of the following:
- HVAC Performance Issues: An error with mounting, connecting, or setting up your thermostat can cause your heating and cooling system to malfunction. The HVAC unit may not turn on when expected or may run continuously, or the fan may not start so air can be distributed properly.
- Injuries: If not careful, you could be injured by misusing tools you’re not familiar with. A shock, burn, or electrocution can occur if you make a mistake with a wire or electrical component.
- Faulty Wiring/Electrical Damage: Modern thermostats often require wiring configurations that are different from those of older units. Any errors can result in damaging a wire, circuit breaker, or electrical panel. An older thermostat may not have a C-wire, but smart units require a functional one to work properly and communicate with your HVAC system.
- Damage to Your HVAC Unit: Making a mistake with thermostat replacement can lead to electrical damage to AC or heating components. Also, if an HVAC unit runs constantly or in short cycles, it can be strained to the point of a breakdown, requiring costly repairs.
- Mismatching the Thermostat with Your System: A mismatched thermostat isn’t only a risk to your comfort. It can be incompatible with a multi-stage system or your home’s zoning requirements. Therefore, your HVAC system may not work properly.
- You May Void the Warranty: Thermostat manufacturers often require licensed HVAC professionals for installation. Otherwise, the warranty may be voided. The manufacturer may consider any damage your fault, so you must pay out of pocket for repairs.
- The Thermostat May Fail Before You Get to Use It: If you don’t get the installation right, you may break the unit before the process is complete. Miswiring the thermostat or making an improper connection can cause too much current to pass through the unit, causing it to fail. But even if it functions, certain features may not work, so you don’t get the full benefits of your investment.
For these reasons, consider hiring a professional to replace your thermostat. This can avoid many hassles. Your local HVAC technician can also explain how to operate the thermostat and find the optimal settings for energy savings.
Steps to Replacing a Thermostat
If you choose to perform a DIY thermostat replacement, it’s important to be careful and follow all the manufacturer’s instructions. Also, pay close attention to any safety concerns and hazards. Assuming you’re not violating any codes or warranty requirements, you can save a few hundred dollars in labor.
However, thermostat installation isn’t for everybody. The following steps can ensure the project goes smoothly and help you determine whether to proceed:
- Find a Compatible Unit: The model must be compatible with your HVAC system. Compatibility means the thermostat must support your heating and cooling system’s features and electrical requirements. Your HVAC system should have a 240-volt connection. If you install a thermostat with an incorrect voltage, you can cause serious damage.
- Read the Manual: There are many thermostat models on the market. Most of them look similar, but each unit may require specific tools and techniques. Read the instruction manual fully before starting the project. Otherwise, the task may take more time than you planned.
- Shut Off Your HVAC System: Turn off the HVAC circuit breaker at the main electrical panel. The wires must be removed from the old thermostat and connected to the new one. This step ensures your safety and protects the system from damage. If you’re still evaluating your HVAC system in the planning stages, the thermostat’s battery backup may hold the settings until you restore power.
- Remove the Faceplate: Don’t do this until the power is turned off. With most thermostats, you can unclip the faceplate by pinching the sides and pulling gently. The unit’s voltage should be listed on the back of the faceplate. Comparing it with the new model ensures you’re installing a compatible unit.
- Install a C-Wire: An old thermostat may have only two wires. New units require five wires. If you don’t have a C-wire (Common wire), one will have to be installed, or you can purchase a 24-volt adapter or a power extender kit. We recommend having a licensed electrician install the C-wire.
- Note the Wiring Configuration: Your system already has a Common wire if the label indicates it or there are five wires behind the faceplate. The wires may be color-coordinated with their respective connections. If not, take pictures to remember the terminal each wire connects to. You can also stick pieces of masking tape to each wire and write a letter to remind you where it goes.
Once you’re familiar with the configuration, disconnect the thermostat wires. They may unscrew from their respective terminals; or, there may be a button to release each wire. To prevent the wires from falling back into the wall, tape them to it or attach them to a pencil.
- Replace the Baseplate: The baseplate of the old thermostat can be removed by unscrewing it. You may also have to pry it from the wall. Retape the wires to the wall after threading them through the opening in the old baseplate.
Examine the exposed area for any damage. The new baseplate may be smaller; if so, cover the extra space with spackle and paint. It will have to dry before you install the new unit. The new thermostat must be level, which can be verified with a level tool or a built-in level if the new unit has one. You can then mark the screw holes.
Now, the new base can be installed. Once the wires are strung through the new baseplate, drill new screws into the holes, in line with the pencil marks.
- Wire the New Thermostat: Follow the instructions and labeling on the unit for attaching the new wires. Some models require opening a connection and placing the proper wire underneath, while others have small screw terminals to attach the wires to. Add the batteries if the thermostat requires them. If you have uncertainties as to wiring and connecting the new unit, stop and contact a professional.
- Mount the Faceplate: The instruction manual should show how to snap or screw on the faceplate. First, double-check the unit is correctly wired, attached, and aligned. Then follow the directions for attaching the new faceplate.
- Turn the Power Back On: Turn on the HVAC breaker and any switches on the unit. Follow the instructions for starting up the system and programming your new thermostat.
Frequently Asked Questions
What Does Thermostat Replacement Cost?
Depending on the type, a new thermostat may cost between $15 and $300. However, hiring a professional comes at a cost (often a necessary one). Your HVAC contractor will charge service and labor fees. According to Angi, an electrician may charge $65 to $100 per hour to wire a thermostat. The job is usually completed in under two hours.
Can I Install Any Thermostat As a Replacement?
The new thermostat must work with your specific HVAC system. Factors to consider include the system’s voltage requirements, whether it is zoned, and the number of heating or cooling stages. Depending on the system, the thermostat may need to be mounted in a specific location.
Where Should a Thermostat Not Go?
Avoid installing a thermostat near an air vent or drafty area. Also, avoid placing it near a window, door, or anywhere it may be exposed to direct sunlight. The unit should also be installed away from heat-producing appliances.
Hire Monarch Home Services for Thermostat Replacement
Our fully licensed and trained HVAC contractors install all types of thermostats, including the latest Wi-Fi thermostats with energy-saving features. EPA- and NATE-certified, they help choose the right unit so you can enjoy improved comfort and ease of use. They also explain how to program the thermostat onscreen or via a smartphone app so you can optimize your indoor comfort. For a free consultation, call (661) 215-6428 today.