Why is My Thermostat Not Working? How to Fix [With Pictures]

Do you ever get that feeling that your thermostat is out to get you? No matter what you do, it never seems to work? When you find your thermostat not working, you probably feel lost on what to do. But you're definitely not alone, as a lot of people have thermostat issues - and they can be extremely frustrating. But don't worry, because we're here to help! Here are some tips on how to troubleshoot and fix this problem so that you can be more comfortable in your home!

SuperTech Can Get Your Thermostat Fixed


DIY Thermostat Fixes

thermostat not working

If you're like most homeowners, your thermostat is one of the most important pieces of equipment in your home. It's responsible for regulating the temperature and keeping you comfortable all year long. So what do you do when your thermostat isn't working? 

Step 1: Change Batteries

Changing out the batteries in your thermostat is one of those little things that can make or break cooling down at home. If you notice a thermostat error, don't hesitate to get its batteries replaced! This is a simple task that only takes a few minutes. To check the batteries in the thermostat, you will need to remove it from the wall. Once you have removed the thermostat from the wall, you will need to use a screwdriver to remove the battery cover. 

Step 2: Check Circuit Breaker

breaker panel box

If your thermostat is not working, you may want to check the circuit breaker. The circuit breaker is responsible for supplying power to the thermostat. If it trips, the thermostat will not function properly. To check the circuit breaker, you will need to locate the breaker box in your home and identify the breaker specific for your thermostat. Then, you will need to switch the breaker off and back on again. 


Step 3: Check Thermostat Programming

If the thermostat is not working, it may be due to a programming error. For the thermostat to operate properly, it must be programmed correctly. Thermostats can be a bit tricky to program, especially if you're not sure which mode is suitable for your home. To make sure the thermostat is properly programmed, refer to its owner's manual, which will provide information on navigating the device's controls and setting it according to your needs. You can learn more about how to recalibrate your thermostat in our blog about thermostats not reaching their set temperature.

Common programming discrepancies include running the thermostat for a heat pump system instead of a furnace and vice versa. Many do not realize that thermostats can be compatible with multiple types of equipment. If the thermostat for your furnace is functioning the way it should for a heat pump, your furnace and AC will begin to compete against each other. As a result, your utility bills will skyrocket.

Some thermostats run on a programmed schedule, meaning their set temperature varies depending on the time of day. For example, it may run the set temperature to be 68 degrees from 7 am-7 pm and raise it to 70 degrees after 7 pm. If it seems like your thermostat has a mind of its own, it may be programmed to run on a pre-set schedule. 

A Smart Thermostat can automatically adjust its set temperature based on how frequently the homeowner is home or away. This feature is meant to optimize efficiency, but the homeowner can disable it if they want.

Lastly, verify that your thermostat is set to Cooling mode if you want air conditioning and set to Heating mode if you desire hot air.

Each thermostat configuration is different, but the owner's manual guides you through the programmable settings on yours. If you are having trouble programming your thermostat, just give us a call.


Step 4: Ensure The Furnace Switch Is Providing Power To The HVAC System

Sometimes your thermostat may not be working due to a problem with your air conditioner or heating system, not because of a faulty thermostat.

If the thermostat is not working, it may be due to a problem with the furnace. The furnace switch controls power to the furnace and must be on for the thermostat to work. To check if it is, you must locate the furnace. The switch will look just like a light switch and be either on the side of the unit or nearby on the wall. If the furnace switch is in a downward/off position, then turn it up/on.

Step 5: Facilitate Air Flow

If your thermostat is not working, you may want to check the airflow. Airflow is a significant factor in how your heating and cooling system performs, as it supplies cool air to the rooms in your home. If it is blocked or restricted, your HVAC system will struggle to match the thermostat's display, causing the thermostat to not function properly. Therefore, check if there are any closed or blocked vents. Then remove any other obstructions to allow for a steady stream of cool air in and hot air out (and vice versa in the winter). 

If your thermostat is not working, you may want to check your AC filters. The filters are responsible for trapping dirt and dust particles. If the filters are not working, the thermostat will not be able to function correctly. When the air filters are dirty and clogged, air will struggle to pass through them. This reduces cooling and heating efficiency as well as strains the HVAC components. If the HVAC system struggles to keep up with the thermostat set temperature, it can explain it not working.

If you need help changing your filters - or if the thermostat still isn't working after trying these fixes - you may need to call a professional for help.

Call SuperTech For Any Of Your Thermostat Needs


Why Your Thermostat Is Still Not Working:

A Bad Thermostat Control Board

If your thermostat is not working, it could be because of an issue with its control board, which communicates with the HVAC system to ensure everything runs smoothly and efficiently. The thermostat control board sends signals to turn the cooling and heating functions on and off. If the thermostat control board is faulty, your thermostat will stop working

Dead Batteries

One of the most common reasons why thermostats don't work is dead batteries. If the batteries your the thermostat are dead, the thermostat will not be functional. Therefore, you will need to replace its batteries. If the thermostat still does not work after you do this, you may need to call a professional for help.


Poor Wiring

The malfunctioning thermostat may be due to faulty wiring. If the device's wires are loose, dirty, disconnected, or bad, the thermostat won't function properly. 

Thermostat Not Programmed Correctly

The thermostat is an essential device in your home. If it is not programmed correctly, you'll experience thermostat problems. The thermostat could be working against the homeowner due to faulty programming. You may have the thermostat programmed for the wrong type of equipment, running a pre-selected temperature schedule, set for the wrong mode, or bad connections. If any of these things happen, don't worry because we can help fix everything by reprogramming your device so it works as expected again.


Faulty High Voltage Wire

An issue with the high voltage wire may be the cause of a malfunctioning thermostat. If there is a problem with the high voltage wire, the thermostat will not be able to signal the HVAC system properly. A high-voltage wire that is damaged, loose, or disconnected causes thermostat problems.

Bad Thermostat

If your thermostat is not working, one of the possible reasons may be that the device itself is just bad. Like all mechanical devices, a faulty thermostat is a fluke that sometimes just happens. A bad thermostat can cause several problems, including not turning on the cooling or heating functions, not reaching the desired temperature, showing an error message, or displaying incorrect temperature readings.


No power: Furnace Switch Off or Circuit Breaker Tripped

An HVAC system needs power to operate, so if it cannot start, you will be stuck with a thermostat that does not work. If so, ensure your furnace switch is on and your HVAC circuit breaker is set correctly.

Blown Fuse

If your thermostat is not working, one possible reason may be a blown fuse. The thermostat cannot communicate when a sudden electrical incident such as a blown fuse occurs.


Problem with AC or Furnace 

Often, your thermostat is not working due to an issue with the air conditioner or furnace. If the thermostat can never satisfy the desired temperature, the problem may originate from your heating or cooling system. In particular, you may find that your AC is not turning on, blowing hot air, leaking water, or freezing. When the AC or furnace is not working, the thermostat will appear not to keep up. Some common problems with the AC or furnace that can create a thermostat problem include a bad blower motor, freon leak, or leaky ductwork. With your furnace, you may find it blowing cold air, leaking, or at the very worst not turning on at all. There are multiple factors at play when you have a thermostat issue. Only an HVAC professional can diagnose the root of AC repair problems and offer technical solutions for them.

On a side note , if there is a problem with your system's auxiliary heat, this will be displayed on the thermostat. 

Poor Airflow 

If the thermostat is not working, one of the possible reasons may be a problem with the airflow. When air is blocked from circulation during the heating or cooling process, the HVAC system can not keep up, and thus the thermostat will not satisfy the desired set temperature. Additionally, when there is an airflow problem, it can cause the furnace or AC to overheat or freeze. A dirty filter, blocked or closed vents, and bacteria in your ducts can inhibit airflow, directly showing up on the thermostat.


How To Keep Your Thermostat Working All Year Long

Your thermostat and HVAC system will function at its best when you need it most if it is maintained in top condition. Regular maintenance will ensure your system is in good working order and help prevent heating and cooling problems. During a tune-up, an HVAC specialist will evaluate all requirements for proper airflow, asses all wire connections, and assess each mechanical component. Unfortunately, many people neglect to maintain their HVAC systems. This can lead them into trouble when they need it most! Luckily for you though, there is now an easy solution- regular maintenance with the specialists will make sure that your system stays in top condition so everything runs smoothly and prevents any problems before they happen. Because of routine maintenance, you won't have to worry about a faulty thermostat ruining your day!

Get Maintenance Done To Keep Your Thermostat Functional


Time To Get Comfortable

So, your thermostat is on the fritz and you're not sure what to do? First of all, don't panic! We know that having no air conditioning or heating in the middle of summer or winter can be a huge headache. But before you start calling around for thermostat repair or a new thermostat installation, there are a few things you can try. If your thermostat is not working, change the batteries, make sure it is turned on, the thermostat is set to the correct mode, check the power supply and airflow. 

If your thermostat is still not working, the best thing to do is call SuperTech - your best AC contractor! They will be able to help you diagnose and repair the issue. Not only will this save you money in the long run, but it will also ensure that your home stays comfortable all season long.

Let SuperTech take care of it for you. We'll get your home comfortable again in no time. Schedule here now!


  • My thermostat didn’t have batteries with the unit.
    My thermostat was blank. We put batteries and at first it wouldn’t come on. Should we replace unit?

    • It’s difficult to determine when a thermostat should be replaced without determining the source of the issue. Typically with thermostats it can be an issue with wiring and in rare times a faulty device.

  • Why do I have no display. Worked fine for 2 weeks. Covered it with paper yesterday to paint. Uncovered today to adjust temp and the screen is blank.

    • Unfortunately, it’s difficult to determine the issue from afar. Sometimes, simple touches can knock a wire loose or disconnect it from power in some way.

    • Yes, you should see it start to cycle through. If it does not reset soon, make sure to check the batteries are installed correctly and the unit is firmly clicked back into place.

  • …and, if the thermostat is electric, and the issue is the heater not functioning… am I being charged for electricity?

    • Any product in your home that is either plugged into an outlet or hardwired into the wiring of your home is using electricity. Though the energy use may be minimal, it does conduct electricity.

    • I’m glad it helped. Thank you for stopping by!

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  • My thermostat is giving the error message that it can’t connect to the wireless network, but it isn’t a wifi thermostat! Both the thermostat and furnace are only about 6 months old. Batteries have all been replaced, breakers are fine… ๐Ÿคท๐Ÿผโ€โ™€๏ธ

  • Had a thermostat installed, and after they left temperature start to drop after you set temperature to temp it climbs up 1 degree then it starts declining temp whatโ€™s wtong

    • Hi Bill! Thank you for stopping by. Unfortunately, with thermostats its hard to determine the issue without looking at it. It can get complicated depending on what kind of system you have installed (the thermostat and the HVAC) as well as the wiring. We do recommend having a licensed technician take a look at everything to determine the issue.

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