How to Tell if Your Thermostat Is Bad-All the Signs

Thermostats are essential systems that regulate temperature changes. For instance, thermostats keep the room warm during cold weather season and vice versa. The thermostat works perfectly after the thermostat sensor opens the thermostat allowing you to regulate temperatures of different rooms. Thermostat exists in different types, such as ecobee4, ecobee3, among others. Thermostats are also used in cars to control coolant that flows and cools the engine.

Sometimes, the thermostat may start failing due to various reasons, such as broken thermostats. In such situations, immediate replacement or fixation is necessary. Therefore, it is important to regularly inspect your thermostat to understand the signs of a bad thermostat. In this post, the information aids in understanding the signs of a bad thermostat.

Signs of a bad thermostat

Some signs and symptoms indicate a bad or a failing thermostat, and sadly, most people usually ignore the signs since they appear to be less severe. The information below describes the signs of a bad or failing thermostat.

1. Inaccurate temperature readings

how to tell if your thermostat is bad

Incorrect temperature measurements are the first and common sign that indicates a failing or bad thermostat. Sometimes, thermostat temperature may be inaccurate and can abnormally increase and decrease. In this case, it is an indication that the thermostat is failing and requires immediate fixation or replacement.

The best solution for fixing the thermostat is by calibrating it. Calibrating a thermostat is easy as long as you follow the recommended steps and you use the appropriate method to calibrate the thermostat. Therefore, it is advisable to fix the thermostat to get accurate room and engine temperature readings to allow the engine to function properly.

2. The thermostat is failing to turn on

The thermostat is failing to turn on

Sometimes, the thermostat may fail to respond when switching on. Several reasons can cause the thermostat not to turn on and function as required. For instance, failure to charge or connect the thermostat to the power supply source causes the thermostat to fail to turn on.

To fix power supply issues, Inspect the thermostat power supply source carefully and identify any faults present. If the thermostat is not connected to the power supply source, establish a connection and then test the thermostat. If the thermostat won’t turn on, check the condition of the switch or the thermostat itself and try fixing them if they are bad.

Further, a broken or damaged thermostat automatically fails to turn on. Once the thermostat completely breaks, it fails to function or even turn on as required. In this incident, immediate replacement is the only solution.

3. The thermostat is not responding to any adjustments

The thermostat is not responding to any adjustments

Once your thermostat fails to respond to any buttons and settings, it indicates that the thermostat is bad or is failing. Ignoring such issues may result in severe damages. For instance, if the car engine fails to respond to adjustments, it can result in severe engine damages.

Also, for room thermostats, the failing thermostat can lead to uneven temperatures in the house. For instance, the thermostat temperature readings differ from actual room temperatures, thus increasing many discomforts. If the thermostat fails to respond to any adjustments, follow the recommended steps and fix the problem on your own. Also, consider contacting a skilled technician if the problem persists.

4. HVAC won’t turn on

HVAC won’t turn on

A thermostat failing to function can result from a poor connection between the thermostat and the HVAC system. Once the HVAC system fails to function, it interferes with the correct functioning of the thermostat. Fixing HVAC and thermostat issues require you to follow the step-by-step guide. First, check the wiring of both the HVAC system and the thermostat.

If the wires are blown out, consider replacing the wires with the new wires that suit your thermostat and HVAC system. If the wires are loosely attached, tighten them using the best wiring tool. Also, consider replacing the thermostat and the HVAC system, especially if they are old.

5. Increased electricity cost

Increased electricity cost

If electricity bills rise irregularly, it can be a sign of a bad or failing thermostat. If the thermostat records inaccurate temperatures, it makes the HVAC system work continuously, leading to more electricity consumption. The more the electricity used, the more the electricity bills.  Also, the air conditioning function constantly consumes more electricity, thus increasing electric utility bills.

Therefore, if your electricity bill rises abnormally, first, inspect the condition of the thermostat if it is functioning normally. Then, consider replacing or troubleshooting the thermostat issues to reduce electricity bills. Also, a reduction in electricity bills enables you to save money for future or emergency use.

6. Irregular functioning of the HVAC system

Sometimes, the HVAC system may fail to turn off or start and stop at irregular intervals. Irregular functioning of the HVAC system is usually a result of incorrect calibration of the thermostat. Calibrating the thermostat is the best solution in such instances. Follow the correct steps when calibrating the thermostat.

Steps of how to test the condition of the thermostat

Steps of how to test the condition of the thermostat

The following steps will help you inspect and test the condition of the thermostat.

Step 1: Test the thermostat temperature recordings

Test the HVAC system by turning it on and setting the room or engine temperatures. For instance, set room temperature to 6 degrees and see if the room temperature changes. If the thermostat fails to respond to changing room temperature, it is a sign that the thermostat is abnormal.

Step 2: Turn on the thermostat

Check if the buttons of the thermostat are in good condition and try turning the thermostat on. Also, try turning the HVCA system on by selecting heat or cool settings.

Step 3: Test thermostat and HVAC system wiring

Open the thermostat and the HVAC system and test the wires attached to both systems. Ensure you screw all wires tightly using an appropriate tool such as a wire cutter, screwdriver, etc.

Step 4: Test the breaker

Switch on the thermostat breaker and see if the thermostat turns on as usual. If the thermostat fails to turn on normally, try troubleshooting the thermostat breaker by resetting it. Resetting involves turning the breaker and the thermostat on and off continuously until the breaker functions normally.

Step 5: Recheck the wiring connection

Recheck the thermostat and the breaker wires carefully once again and try fixing the wires correctly to make your thermostat function normal.


Suppose your thermostat fails to function as normal. Then, there is a bigger chance that the thermostat is failing or is damaged. Luckily, the information above will help you easily identify a bad or failing thermostat. Also, the information will help you diagnose and test the condition of your thermostat.

Fixing thermostat problems is easy as long as you follow the recommended steps. Finally, follow the manufacturer’s manual book instructions when fixing bad or failing thermostat problems to get an accurate outcome.

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