Thermostat Says Heat On But No Heat – Updated Guide (2023)

It is a commonly faced issue that your thermostat goes into a condition where it says that the heat is currently ON but you feel no difference. It is like that there is some problem within the thermostat which is causing this issue to occur. The good news is that you don’t have to worry if this issue occurs as it is completely solvable. However, this problem could occur due to many reasons which we will be discussing below.

Honeywell Thermostat Heat Not Working Could Be Due To Incorrect Wiring, Faulty Fuses, Tripped Breakers, A Broken Hvac System Or The Thermostat Might Be Broken Itself.


The first thing which you need to understand is that if you purchase any smart product then it is obvious that you deal with certain issues like one mentioned above. Getting tensed in such situations is not a solution, in fact you have to give a try to solve the issue.

Solving tech-related issues will expand your knowledge and you will be amazed by how much you have gained at the end of this solving process.


In this section of the article, we will be discussing the common problems which might occur along with their fixes.


If you face the heating issue right after you have installed the thermostat then it means there must be some issue with the wiring. You might have unintentionally connected a particular wire to a wrong terminal. For instance, during the installation you might have interchanged the W and Y wires. Your action will make the cooling unit to work even though the thermostat is calling for heating.


You will have to cross check the connections of wires. First of all check the wiring within the wall plate of your thermostat and then check the wiring at the furnace’s end. Make sure you have attached all the wires correctly and into the relevant ports. If you don’t have much knowledge regarding this then it is recommended that you take professional help.


You might have noticed that there are copper wires present within the cable of your thermostat. These wires can easily shutter if they are flexed too much. The other case is that the installer might have put too much pressure on the wires while stapling. It is a difficult issue to detect at times but when it does then it will definitely cause a fault in the heating unit of your thermostat.


The first thing which you need to do is replace the wire as soon as possible which is connecting the furnace and thermostat. Do not staple the wire tightly and avoid fastening it too hard.


There is an option in your thermostat which allows you to set the temperature lower or higher than the heating or cooling systems can deliver. But even after doing this, the thermostat will provide you with the heat it is capable to deliver. On extreme cold days, you might set the heat temperature to 76 degrees but your thermostat is capable to operate on 72 degrees. In this case, you might feel that the thermostat isn’t working fine but actually it is working absolutely fine.


Make sure that you don’t set the temperature too high or too low. Set your thermostat to a realistic temperature value. Realistic temperature means a temperature at which your home heater works up to its full capability. After doing this, if you still doesn’t feel comfortable then your furnace might be at fault.


If you are thinking that it is the only heating issue that you have to come across then you are wrong. If you own a Honeywell thermostat then there is a high probability that you might face issues like thermostat heat won’t turn ON and thermostat heat ON blinking etc.


If your furnace’s fan blades and filters are filled with dirt or are clogged then it will restrict the hot air to roam around in the room. This problem could lead to zero heat output. Along with this the heat efficiency will also be reduced and you will have to face the consequences.


  1. Clean the filters thoroughly
  2. If the time duration of the filters has exceeded then it is important to replace them
  3. Hire an expert to get the inner components of your thermostat cleaned on a yearly basis



Wrongly sized furnace system leads to many problems. Even though the price of these furnace systems is comparatively low but they will not satisfy your heating requirements. Even though you wouldn’t observe any problem at the present time but you definitely will on extremely cold days.

Another demerit of such thermostats is that their compressors will soon stop working like they used to previously. This issue will occur because the valves and the refrigerant will eventually start leaking. If this is the situation then you will notice that no heat will be provided even though your thermostat is still running.


  1. Hire an HVAC system expert to keep the refrigerant pressure checked. If the level is below than required one then make sure to bring it into the line which is mentioned as per your HVAC system’s specs
  2. Hire a tech to observe the head and tail pressures when the compressor runs. If this ratio is too low then you might want to get your compressor replaced
  3. You could also replace the cross over valves if the system gets 15 – 20 years old. If this is not the case then adopt another approach



Dirty or clogged heat pump coils reduce the air flow through the evaporator unit inside and condenser outside. This will greatly affect the efficiency of your heating system and will prevent the system from performing like it should.


  1. Get an access to forced air and use it to clean the metal fins that have become clogged with dirt. If you cannot do it yourself then hire a technician to do the job
  2. You could also use brush sweepers or vacuum cleaners to clean the fins. Make sure to not put much pressure on the fins as they are delicate and might get damaged easily



Honeywell thermostat flashing heat ON but no heat is basically an issue with many potential reasons. One of them is extreme weather conditions. When the weather is unbearably cold then your central heating system becomes incapable to keep the inside temperature cozy. In such weather conditions, you will feel like the thermostat isn’t working at all.


  1. Close all the points from where the cool air could enter for example the windows and drapes
  2. In case of multi-stage heating system, make sure all the stages are working accordingly
  3. Double-pane or triple-pane your glass windows so that the heat could be kept inside the home



If one stage system shows incompatibility with multi-stage systems then you will not receive enough heat to make the room temperature cozy.


  1. Honeywell thermostat no heat might be due to the presence of faulty compressors
  2. The interchanging of wires might become a cause that your thermostat is providing insufficient heat



If the insulation of your house is insufficient then this will bring more damage. The insufficient insulation will allow the outside air to enter the house and as a result you will see that the temperature fluctuates.

The heating unit is already struggling hard to keep up with the temperature and these additional factors will contribute more into the cause. However, it is recommended to get more insulation or just face the situation as it is.


  • Find the leaking spots inside your house. Examine carefully and once found, make sure to seal them with some hard foam or with any other similar material
  • Make sure the louvers of your exhaust fans turn OFF when the exhaust fans turn OFF themselves
  • Replace your single-paned windows with triple or double panning as soon as possible
  • Replace the basement windows with glass block units which will take off the burden from the system


If you want higher temperature in your home then follow the below mentioned points.

  • Add more heaters in your house
  • Try to upgrade the central heating system of your house to a larger one
  • Examine the insulation around your house, if not sufficient then add more of it
  • Get better windows and doors installed in your house so that the leaking spots become less in number


Honeywell thermostat heat ON but no heat providence issue is becoming more and more common. This is because many people don’t know the exact reason behind this or they don’t know how to solve the issue. Once you acquire the required knowledge then you will easily be able to figure out the root cause of any problem. If you give a proper read to similar articles then you will get to expand your knowledge on technical domain.

We have told you everything about the heating issue which might be encountered by you in the future or you might have already encountered it. Make sure that you give this article a proper read because that is the only way to get this issue resolved.


Q – My Thermostat Is ON But No Heat, Why?
A – Your thermostat might be ON but still it isn’t providing sufficient heat could be due to the presence of faulty compressors, incorrect wiring, and broken thermostat or damaged fuse etc.

Q – How Can We Solve Honeywell Thermostat Heat ON Issue?
A – To solve Honeywell thermostat heat ON but no heat issue we will need to check various internal components like the working of compressors, the air filters and fan blades should be unclogged and other similar stuff like this.

Q – Why Is My Thermostat Not Heating?
A – Your thermostat isn’t heating because of the following reasons:

  • Insufficient insulation
  • Faulty compressors
  • Broken thermostat
  • Broken HVAC system
  • Dirty and clogged air filters
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Hello there, I'm Melvin Castillo, a highly skilled tech author specializing in home appliances. With over a decade of experience in the industry, I've become an authority on home appliances. I pride myself on my ability to provide concise, clear, and accurate information that helps my readers make informed decisions when it comes to choosing the right home appliances for their needs.

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