Thermostat Loses Power Intermittently [Reasons & Fixes]

A properly functioning thermostat is essential for keeping your home at a comfortable temperature. Unfortunately, many homeowners experience issues with their thermostats, such as losing power intermittently. 

This issue can be caused by a few different things and can lead to an uncomfortable home environment.

So, what should you do when your thermostat loses power intermittently

Start off by restoring the circuit breaker. Then, clean the compressor coils and components. After that, clean the flame sensor. Next, stabilize the voltage of your house’s electrical system. Then, replace and rewire the thermostat wires. Afterward, clean the air vents, filters, and blower wheel of your AC. Finally, unclog the drain pipe.

Along with this information, you will need precise instructions to resolve these issues. Read till the end to know more.

7 Reasons and Solutions behind Your Thermostat Losing Power Intermittently

There are a couple of reasons behind a thermostat losing power. Knowing these reasons beforehand will give you insight into the solutions. 

Here are 7 reasons that can steal the power intermittently from your thermostat along with their solution-

Reason 1: Circuit Breaker Has Tripped

This is one of the most common reasons behind any thermostat losing power. In every house, there is 1 circuit breaker that controls the thermostats.

Circuit Breaker Has Tripped

If the circuit breaker has tripped, the thermostat may lose power every so often. This can also lead to situations where there’s no power in the thermostat!


Here are the steps to get rid of this issue-

  • Firstly, turn off all the devices and appliances that use electricity.
  • Secondly, find the electric circuit panel which houses all the circuit breakers. Open the lid of the panel.
  • Thirdly, find the specific circuit breaker that controls your thermostat. Usually, thermostats use 24V AC circuits. Check if it’s tripped or not. If the circuit breaker tripped, proceed to the next steps. If not then go to the next solution.
  • Fourthly, reset the circuit breaker. To switch off the breaker, move the switch or handle to the “off” position.

    Afterward, switch it back on. To ensure safety, it is recommended that you stand away from or to the side of the panel.

    That way, you can protect yourself from any potential sparks that occur while moving the breaker.
  • Finally, close the lid of the panel.

Reason 2: Damaged Thermostat Wiring 

When the wiring of the thermostat gets damaged, it can steal the power of the thermostat at times. This way, the thermostat loses efficiency and loses power intermittently.


Any damaged wiring inside the thermostat may be dangerous. The best solution for this is to get replacement wires for your specific thermostat and rewire it.

Damaged Thermostat Wiring

To rewire the thermostat-

  • Firstly, turn off the power to the breaker box of your home.
  • Then, using a screwdriver, remove the cover of your thermostat.
  • After removing the cover, you can take a picture of the wiring diagram as a reference.
  • Next, disconnect each of the wires with the appropriate screwdriver and remove the backplate.
  • After that, replace the old wiring with the new ones. Contact your thermostat manufacturer to get the replacement wires.
  • Then, attach the backplate and start connecting the new wires. You can use the reference photo you’ve taken before to restore the connection. Secure the wires with screws.
  • Finally, restore the thermostat cover and turn on the power.

If you’ve got a 2 wire thermostat, you can upgrade the 2-wire thermostat to a 4-wire. This will surely increase the stability of your thermostat.

Reason 3: Compressor’s Not Working

The compressors help your air conditioner release heat buildup. When a compressor doesn’t work properly, the air conditioner won’t work as well.

Moreover, it may affect the connected components, which include the thermostat as well. A faulty compressor can easily disrupt the continuous flow of power to the thermostat.


To get the compressor working, follow the steps here-

  • Start off by turning off the electric breaker, to be on the safe side.
  • After that, remove the side and top condenser covers to access the coil. Along with that, unscrew the fan unit from the condenser too.  
  • Then, you have to clean the compressor. Dirt, debris, and dirty condenser coils stop the compressor’s workflow. It causes the compressor to overheat and shut down.

    Start cleaning the condenser coils by vacuuming the coils, fins, and protective grille. You can use water and AC coil cleaners.

Try to foam all the parts mentioned above. Then, rinse them with water.

  • Finally, let the components dry out fully. You can then screw the fan assembly back in and restore the side and top condenser cover.
Compressor’s Not Working

Along with getting the compressor back to a working state, this cleaning procedure will improve cooling efficiency too!

Reason 4: Flame Sensor is Dirty or Has Gone Bad

A flame sensor in a thermostat notifies you if there’s a flame when the gas valve is open. No flame will result in shutting off the gas inside the furnace.

So when the flame sensor is dirty or goes bad, the flame won’t register. As a result, your furnace might shut down intermittently, causing the same for the thermostat as well.


To clean the flame sensor-

  • Firstly, find the flame rod sensor inside the furnace. It should be just outside of the burner assembly.

    Turn off all the gas supplies and remove the access panel of your furnace. Then, remove the flame sensor using a hex screwdriver set.
  • Then, take steel wool and start rubbing the flame rod sensor to remove the buildup of carbon. Cleaning this soot can restore the effectiveness of the flame sensor.

    Make sure you do not put too much pressure, do it gently. You may wipe the flame sensor rod with a soft cloth after the cleaning.
  • Finally, attach the flame sensor back in and secure it with the hex screws.

If the flame sensor is still disrupting the thermostat, consider replacing the flame sensor. Contact your furnace manufacturer and get a replacement!

You can also try replacing the thermostat if the problem exists. You don’t have to spend too much though, just get the cheapest and best thermostats for under 100$

Reason 5: Low Voltage Issues

When the overall voltage of your electrical configuration of the house gets low, the thermostat may lose power. Voltage fluctuation issues can damage other appliances and components, along with the thermostat.


To get rid of the voltage fluctuation, you must connect a voltage stabilizer to your AC unit. Make sure the voltage rating of the stabilizer is higher than your air conditioner.

Similarly, do this for your TV, microwave, and fridges as well. Costly appliances like this might break down due to unstable voltages.

If that still doesn’t solve the problem, contact an electrical mechanic. Have the mechanic inspect the circuitry of your house and solve it for you.

Reason 6: Short Cycling

Short cycling in thermostats can cause the furnace to shut off at random times. As this can be frustrating, it can also be dangerous! 

If short cycling occurs in a thermostat, it has the potential to damage the inside components. 


To stop the short cycling of the thermostat, do this-

  • Start by replacing the air filters. Dirty air filters are the number 1 cause of this issue.
  • After that, clean the blower wheel and its blades. You can use this video as a guideline for this task-
  • Finally, check the air supply vents. Closed or blocked air supply vents may just be the reason for the short cycling. 

Reason 7: Clogged Air Conditioner Drain Pipe

In most cases, the condensation inside an air conditioner unit flows through the drainpipe. Sometimes dirt and grime get stuck inside the drainpipe. 

If the drain pipes of the air conditioner are clogged, the water starts backing up and overflowing. The thermostat losing power can be caused by this reason. Any water leak through the thermostat wall is a common symptom of this problem.


To get rid of this problem, you’ll need to unclog and clean the drainpipe. To do so, follow the steps below-

First, use a vacuum cleaner to vacuum one end of the drainpipe. It will get rid of the dust buildup inside the drainpipe.

Clogged Air Conditioner Drain Pipe
  • After that, use a steel wire to unclog the drain pipe. Insert the steel wire in the drainpipe and pull it back and forth. 

It will force the drainpipe to drain out. Do this on both ends of the drainpipe.

  • Finally, use a water hose and push water through one end of the drainpipe. The water will get rid of all the sediment and other chemicals inside the drainpipe.

Frequently Asked Questions (FAQs):

What problems can a faulty thermostat cause?

A faulty thermostat can cause overcooling and overheating. Since the temperature control is messed up on a faulty thermostat, this is the consequence. It also has other problems like leakage issues with the coolant, noises, etc. Any faulty thermostat should be fixed as soon as possible to mitigate the problems.

What is the life expectancy of a thermostat?

The life expectancy of a thermostat is around 10 years. But like other devices, it does depend on a few factors. The model, build quality, and type of thermostat also alter the life expectancy. Generally, a manual thermostat lasts the longest. With time, many problems occur with every type of thermostat. 

Is it bad to change the thermostat settings often?

Yes, changing the thermostat settings often is bad. It has many adverse effects. If you change the thermostat settings often, the thermostat will wear down quickly. Also, electricity and money can be wasted by this act as well.


That was all the information you have to know when you find that your thermostat loses power intermittently

If you’re stuck with a problem and unable to fix it, don’t stress. Contact your local air conditioner mechanic to fix the problem for you!

Have a great day.

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