

Why Is My Thermostat Not Working?

John Turpin is our resident home service repair expert here at Service Direct. He’s got the knowledge and experience to help homeowners like you make sense of most home repair issues. And with Service Direct, we connect you with top-tier service professionals to help with any repairs needed.
Learn the Many Reasons Why Your Thermostat Has Stopped Working
The thermostat plays a crucial role in maintaining a comfortable indoor environment by controlling the heating and cooling systems. But it can be quite frustrating when your thermostat suddenly stops working or fails to respond to temperature adjustments.
It happens for various reasons, which are what this article is all about. We’re here to explore some of the common reasons why your thermostat is not working. At the same time, we’ll share troubleshooting steps to help you identify and resolve the problem.

Common Reasons and Solutions to a Thermostat Not Working
Power Issues
When your thermostat is not working, the first step is to ensure it has power. If it is wired to your home’s electrical system, check if it is properly connected. Verify that the circuit breaker associated with the thermostat is not tripped. Also, inspect the fuse box to see if any fuses need to be replaced. If your thermostat is battery-operated, replace the batteries and confirm if they are correctly inserted.
Incorrect Temperature Setting
Why is the thermostat not working? Sometimes, the issue might be as simple as an incorrect temperature setting. Double-check the desired temperature setting to ensure it aligns with your comfort preferences. If it is set too low or too high, it may not activate the heating or cooling system.
Loose Wiring Connections
Faulty or loose wiring connections can disrupt communication between the thermostat and the HVAC system. Inspect the wiring connections behind the thermostat and ensure they’re all securely attached to their respective terminals. If you find any loose or disconnected wires, gently reconnect them. Also, tighten any screws or terminals as needed.
Dirty or Malfunctioning Thermostat
Over time, dust, dirt, or debris can accumulate inside the thermostat and interfere with its sensors and switches. It could be why your thermostat is not working, which is fortunately easy enough to deal with. Use a soft brush or compressed air to clean the thermostat and remove any buildup. But if cleaning doesn’t resolve the issue, you might have to replace it with a new one.
Faulty Temperature Sensor
The temperature sensor is responsible for accurately detecting the room temperature and sending the information to the HVAC system. If the sensor is malfunctioning, it can lead to incorrect temperature readings and erratic thermostat behavior. Contact a professional technician to test and replace the faulty temperature sensor if necessary.
Compatibility Issues
Have you recently installed a new thermostat? Are you sure it’s compatible with your HVAC system? Different systems require specific thermostat models to function properly. Check the installation instructions provided by the thermostat manufacturer or consult with them directly to ensure compatibility. Mismatched or incompatible components can lead to malfunctions or improper operation.
Our resident home repair guru, John Turpin, explores the common reasons why your thermostat isn’t working properly as well as some expert tips and DIY solutions.
The Thermostat Is Not Level
Is your thermostat not working? Does its temperature readout different than the room’s actual temperature? It’s possible this is because the thermostat is not level on the wall. Keep in mind that thermostats have a mercury bulb, which has to be level for it to operate. If this is the problem with your thermostat, turn off the power supply first and then unmount the device. Using a level, change the position of the thermostat and ensure it’s perfectly level this time.
Electrical System Problems
Issues with the electrical components of your HVAC system, such as a malfunctioning control board or transformer, can prevent the thermostat from working correctly. These problems require the expertise of a professional technician to diagnose and repair. They’ll be able to identify and resolve any underlying electrical system issues with their expert knowledge and tools.
Sensor Placement Issues
For thermostats with remote temperature sensors, it’s essential to position them correctly for accurate temperature readings. Ensure that the sensor is placed away from direct sunlight, drafts, or heat sources that could influence its readings. Verify that the sensor is properly connected to the thermostat and securely mounted.
Aging or Defective Thermostat
Thermostats eventually deteriorate or become defective, especially if they are old or have experienced damage before. If you have exhausted all troubleshooting steps and the thermostat is still not functioning correctly, it may be necessary to replace it with a new one. Consult with a professional technician to select a compatible and reliable replacement thermostat.
Environmental Factors
Environmental factors can impact thermostat operation. For instance, if the thermostat is located near a heat source like a fireplace or a lamp, it may falsely sense higher temperatures and not activate the heating system when needed. Ensure that the thermostat is installed in a location free from such influences to prevent inaccurate readings and ensure proper functionality.
Remember, while these explanations provide guidance for troubleshooting issues, it’s always recommended to seek the assistance of a professional HVAC technician. This is true, especially if you are unsure or unable to resolve the problem yourself.

When to Call a Pro
Thermostats, like any electronic device, are subject to wear and tear, electrical issues, and component failures. Various factors such as age, improper installation, power surges, and environmental conditions can contribute to thermostat malfunctions. Common problems include a blank display, inaccurate temperature readings, and failure to turn on or off.
In such cases, troubleshooting steps can help identify and resolve minor issues. But if the problems persist or the thermostat exhibits significant signs of malfunction, it may be necessary to replace the thermostat or seek professional assistance to ensure the proper functioning of the heating and cooling system.
How do I know if my thermostat is not working?
If your thermostat is not working, you may notice several signs such as a blank or unresponsive display, failure to turn on the heating or cooling system, inconsistent temperature readings, or a lack of response to adjustments. Also, if your home is significantly colder or warmer than the set temperature, it could indicate thermostat issues.
How do I adjust my AC thermostat?
To adjust your AC thermostat, start by locating the temperature control buttons or touchscreens on the thermostat. Then, either press the up or down arrows to increase or decrease the desired temperature, or use the “+” and “-“ buttons on the touchscreen. Make the necessary adjustments and the AC system should respond accordingly.
How do you manually reset a thermostat that’s not cooling?
To manually reset a thermostat that’s not cooling, first, ensure that the thermostat is set to the “off” position. Then, find the circuit breaker that controls the power to the HVAC system and switch it off. Wait for a few minutes before switching the circuit breaker on. Finally, set the thermostat to your desired cooling temperature, and the system should reset and start cooling.
Where is the thermostat on my AC?
The thermostat for your AC system is typically on an interior wall, preferably in a central area of your home. It’s usually placed at eye level for easy access and is connected to the HVAC system via wiring. Look for a rectangular-shaped device with a display and control buttons or a touchscreen.
What is the ideal AC thermostat setting?
The ideal AC thermostat setting can vary depending on personal preference and the climate you’re in. Generally, a recommended starting point is to set the thermostat to around 78 degrees Fahrenheit (23.5 degrees Celsius) for cooling. This temperature provides a balance between comfort and energy efficiency. But feel free to adjust it based on your comfort level and energy-saving goals.
Hire a Local HVAC Expert
Pros have the expertise and experience to diagnose and resolve complex issues, ensuring optimal comfort and efficiency of your home. With their help, you’ll have fewer things to worry about when it comes to your thermostat just reach out using the phone number or form on this page.