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Why Does My Thermostat Have No Heat : How To Fix

Depending on what part of the country you currently live in, it can get extremely cold during the winters. If that is the case, then it is most likely that you have a thermostat in your home to keep yourself warm and cozy. However, the last thing you would want to face during harsh winters is any kind of issue with your thermostat.

And unfortunately, one such issue which is quite common with all kinds of thermostat is the thermostat saying that heating is turned on but there is no heat output. To help you prevent and fix such an issue for keeping yourself warm during the winter, we are here with a complete guide on why your thermostat has no heat. You can simply go through this guide till the end to learn everything regarding this issue.

Why Does My Thermostat Have No Heat?

If you are facing any heating related issue with your thermostat, then you must be wondering the root cause behind this issue in the first place. Thankfully, this issue is most probably caused by something small and not any major faults. Generally, this is caused by faulty sensors or incorrect settings with your thermostat. As a result, even if you have turned on your thermostat, it may still output no heat.

How To Fix A Thermostat Having No Heat?

Fortunately, since most of the common issues found in thermostats are quite small and basic, fixing them is also quite easy. This means that if your thermostat has heat turned on but it does not have any heat, fixing it can be quite easy. You simply need to the following fixes one by one, and one of them will certainly fix your thermostat and turn on the heating without any issues:

1. Dirty Thermostat Filter

To ensure the longevity of your thermostat, all thermostats have a filter for the furnace. However, if this filter itself is dirty, it can get clogged up. Because of this, the furnace of your thermostat will not get enough air which will result in poor heat output. So, you should try cleaning and even consider replacing your thermostat filter to see if that fixes the issues. If you regularly use your thermostat, then it is recommended to clean or replace the filter every 1 to 2 months.

2. Disabled Gas Supply

Out of all the various thermostats available in the market, gas powered thermostats are one of the most common ones. And if you are familiar with gas appliances, then you must know that all of them have a gas valve including thermostats. Thus, if your thermostat is not working well, then you should check if the gas valve is turned off. If it is, then you should open the valve so that the furnace can get gas supply and produce heat effectively.

3. Incorrect Thermostat Settings

If you have ever used a thermostat in the past, then you must know that all of them have a temperature setting. Once your rooms reach the temperature that you have selected, then the thermostat will stop the heat. This means that if you have accidentally set a very low temperature, then your thermostat will not start in the first place. Hence, ensure your thermostat is set to the temperature you want to use.

4. Disconnected Furnace Power Source

If you are using an electric thermostat, it is vital to ensure that the furnace is getting enough power. Without enough electrical power, your thermostat’s furnace will not be able to produce heat at all. Generally, this can be caused by any tripped breakers in your home which may have disconnected the furnace’s power source. If so, turn on all tripped breakers and try using your thermostat again.

5. Dirty Pilot Ignitor

Apart from a turned-off gas valve, another common issue which is found in gas-powered thermostat is a dirty pilot ignitor. To start a gas-powered thermostat, the gas inside the furnace is ignited using a pilot ignitor. As a result, if the pilot ignitor is dirty or faulty, then the furnace will not turn on because of which your thermostat will not be able to produce any heat.

6. Clogged Fan Blades And Filters

Once the heat is produced in your thermostat’s furnace, this heat is ventilated all over your home using a ventilation system. Although, in some cases, the fans and filters of this ventilation system can get clogged up with time. And as you would expect, this will prevent hot air circulation around your home resulting in poor heating performance. So, you should check all the fans, fan blades, and vent filters of your thermostat and make sure that none of them are clogged.

7. Sensor Malfunction

To achieve your desired room temperature, all thermostats use temperature sensors. While these sensors are crucial for thermostats, they can also make your thermostat useless if the sensors are faulty. Any faulty thermostat sensors can tell your thermostat that your rooms are already warm. And in this case, the thermostat won’t produce any heat even if the rooms are actually cold.

8. Incorrect Thermostat Wiring

Similar to the sensors of your thermostat, there are many other electrical components which might not be working properly. And in most cases, it is the wiring of these electrical components which might be incorrectly connected. As you would expect, this can lead to all kinds of issues, including your thermostat not outputting heat.

9. Circuit Breaker Issues

Just as we discussed earlier, any tripped breaker can cutt off the power supply to the furnace of electrical thermostats. Similarly, even if a breaker is not tripped, your thermostat may still not get enough power if any of the circuit breakers is faulty. Hence, you should look out for any tripped or faulty circuit breakers in your home. It is quite common for electric thermostats to face issues because of circuit breaker issues.

10. Low Battery Issues

If your thermostat is not working properly, it is possible that the issue is not with the thermostat but rather with the thermostat controller itself. Usually, you will find issues with thermostats if the thermostat controller has run out of power. To be more exact, you should check the batteries installed in the thermostat controller and replace them if they have run out.

11. Dirty Flame Sensor

Another sensor which can fail in a thermostat happens to be the flame sensor. Just as you can guess by the name, the flame sensor of a thermostat is there to confirm that flames have been ignited inside the furnace. However, in case of a sensor failure, the thermostat will not know whether the furnace is working. And if there are any issues with the furnace and flame sensors, your thermostat won’t output any heat.

12. Heat Pump Coils Frozen

If you are familiar with thermostats, you must know that they have heat pump coils used for heat exchange. Without these coils, your thermostat won’t be able to perform well. And one common issue related to the heat pump coils of thermostats is that they can get frozen during the winters resulting in poor heat exchange.

13. Undersized Heating System

Lastly, there is a possibility that your thermostat is working completely fine but it is struggling to keep your home warm because of either the size of your home or the extreme cold in your area. In either case, it simply means your thermostat is not powerful enough to do the job. Thus, you should consider upgrading your thermostat to a more powerful unit.


Since having a thermostat and using it during the winters is quite important for keeping yourself warm, the last thing you would want is to face any issues with your thermostat. And even though it is quite common to face issues with the thermostat turned on but not outputting heat, solving them is much easier than you think. We have already discussed a detailed guide on why your thermostat has no heat. As we have covered all the major solutions, fixing this issue should be quite easy. And if this guide has helped you fix your thermostat having no heat, then leave your thoughts and suggestions in the comments section below.

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