9 Reasons Aircon Not Cold and how it can hurt electricity bills

9 Reasons why Aircon Not Cold how it can hurt electricity bills

Why is my Aircon not Cold?


There can be a lot of reasons why your Aircon is not cold. And you may require an Aircon technician to check on this to find out the exact reason. However in this article we will explain 7 reasons why your Aircon is not cold. Furthermore we will also show you some simple steps for you to troubleshoot this issue. There is also a section for users with Aircon that is not cold only in one room. In addition we will talk about  how different brands may affect the coldness level of the unit. And the estimated cost of fixing this issue. Lastly, we will explain how Aircon not being cold may affect your electricity bill.


Aircon Blinking Lights


If your Aircon is blinking light, that means that there is an error with the unit. The Blinking light will reflect an error code. For example the number of time Mitsubishi Aircon blinking light will indicate a particular error. 7 times usually means that the PCB is malfunctioning. Hence, if there is an error with the system. The system may shut down to prevent your Aircon unit from further damaging the system. Hence your Aircon is not cold.


Low Aircon Gas Level


If your Aircon gas level is insufficient. Your Aircon may not be cold enough or it may be totally not cold at all. That is because the Aircon unit requires a sufficient pressure level for the blower wheel to blow out cold Air. In some Aircon brands such as Daikin Aircon. Your Aircon system will stop functioning completely. It will result in your Aircon blinking instead. However, for non inverter Aircon there may not be blinking light.


Dirty Evaporator Coil 




Other than insufficient gas level, this is actually the most common reason why your Aircon is not blowing cold Air. Dirty evaporator coil will make the fan coil unit inefficient in receiving the cold Air. It will “clog up” the fan coil unit, hence the cold Air will not be transferred to the blower efficiently. Hence resulting in the Aircon not cold. If the evaporator coil is extremely dirty, you may require Aircon chemical overhaul to solve the problem. Aircon normal servicing may not suffice.


Compressor Not Working


The reason why your Aircon is not blowing cold air could be that your Aircon compressor is malfunctioning. Hence the compressor cannot compress cold Air and supply it to your fan coil. In most cases your fan coil unit will be showing blinking light instead. However, for certain brands there may be no error code shown.


Aircon Thermistor Malfunctioning


If your Aircon is cold for some time and it turns off by itself follow by blinking light. It may be that your thermistor is malfunctioning. The thermistor’s resistance value serves as an indication to tell the compressor to work harder or less hard. So that there is the right amount of cold Air supplying to the fan coil unit. Hence if the thermistor is malfunctioning. The Aircon unit will not be blowing cold air.


Dirty Blower Wheel 


Dirty Blower Wheel


Dirty blower wheel and dirty evaporator coil problem can both be resolved by  Aircon servicing. However, not all forms of Aircon servicing can solve the dirty blower wheel issue. For example, if your Aircon technician only vacuums the evaporator coil without brushing the blower wheel. Your blower wheel may still be dirty. And a dirty Aircon blower wheel will prevent the Air from blowing out efficiently. As a result you will feel that your Aircon is not blowing out cold air.


Malfunctioning Parts


Other than the Aircon thermistor, there can be other Aircon spare parts that cause your Aircon to not be blowing cold Air. For example, your Aircon may have a broken fan blade in the outdoor condenser unit. A broken fan blade in the outdoor unit will cause the hot air outside to not disperse properly. Resulting in an overheated Aircon compressor. Which will prevent your Aircon from being cold at all. Other than a broken fan blade. The other 2 most common Aircon spare parts that malfunction are Aircon pcb and Aircon fan motor. These broken spare parts will cause the Aircon system to stop functioning. Hence resulting in the Aircon not cold.


Insufficient BTU


Do you realize? If you turn on your Aircon in different periods, you may require different temperature settings to achieve a similar cooling level? That is because the outdoor temperature level can affect the coolness of your unit. For example, if the outdoor temperature is very hot, the condenser unit will need to work harder to supply the same amount of cold Air to the fan coil unit. Similarly, the BTU of your Aircon unit may be enough during colder periods. However, in extreme temperatures, the BTU may not be sufficient as there are extra heat sources that your Aircon will have to cover. Resulting in a situation in which your Aircon is not cold.


Compressor Overheating


If your Aircon condenser unit is very dirty. It will close up the fins of the condenser unit and the hot Aircon at the compressor will not be able to disperse efficiently. Hence this will result in overheating at the compressor. An easy way to solve this problem is to do a chemical wash of the compressor unit.

Simple Steps to Troubleshoot Aircon not Cold

1. Stand near to the blower, inspect if your Aircon is totally not cold or a little not cold.

aircon not cold step 5

2. Check if your Aircon is blinking light. If the light is blinking take a video of the sequence.

aircon not cold step 2

3. Detect if the outdoor compressor fan is running or not.

aircon not cold step 3

4. Check how many Aircon units that are connected to one compressor are not cold. One or all?

aircon not cold step 4

5. Take a photo of the model number of the unit.


If the Aircon is blinking light


Supposing your aircon unit is blinking light, simply check the error code of the Aircon unit. It will be extremely easy to check the error codes of Daikin, Panasonic, York, Midea and Mitsubishi heavy industries. For other brands it may be more difficult.


Is the Aircon a little not cold?


On condition that the Aircon unit is a little not cold, it may be due to insufficient gas level.


If Aircon not cold in one room


If the Aircon unit that is not cold is connected to a multi split condenser unit. And that Aircon is not cold in one room only. It could be that a part in the fan coil may be malfunctioning. Typically fan coil unit parts are cheaper than parts found in the condenser unit. However, there can be exceptions to this case. For example, outdoor thermistors in Daikin Aircon can result in Aircon not being cold in one room only.

Does the Aircon Brand Affect the Coldness of the Unit?


Generally speaking, the above reasons why your Aircon is not cold is universal across all Aircon. However, there may be some Aircon brands with peculiar problems that may affect the coldness of your unit.


Daikin Logo  Daikin Aircon not Cold   


If your Daikin Aircon is not cold. Especially if it is not cold in only one room. It may be a result of the thermistor or ev coil malfunctioning in the condenser unit. There will be many technicians that deduce it is the indoor unit causing the problem. However, for Daikin Aircon it is extremely important to check the outdoor unit as well to figure out the root cause of the problem.


  Mitsubishi Aircon not Cold


If Panasonic Aircon is showing a fan motor error code, it may not be that the Aircon is not cold due to fan motor malfunctioning. The error code may be caused by PCB failure instead.

Hence, it takes trial and error sometimes to troubleshoot Panasonic Aircon when it comes to PCB or fan motor error in the outdoor unit.


Panasonic Aircon not Cold


The reason why your Aircon is not blowing cold air could be that your Aircon compressor is malfunctioning. Hence the compressor cannot compress cold Air and supply it to your fan coil. In most cases your fan coil unit will be showing blinking light instead. However, for certain brands there may be no error code shown.


Estimated Cost to Fix Aircon Not Cold Issues


These are some of the estimated costs to fix aircon not cold issues. There may be other parts required to fix this issue. However it will very much be dependent on the model number and parts needed.


Description Price
Pressure test  $190 onwards
Aircon Gas Top-up $80 onwards
Chemical Overhaul  $130/unit
Normal Servicing  $18/unit onwards
Aircon Repair  $130 onwards


How Aircon Not Cold can Hurt Your Electricity Bill?


Situations in which it will NOT hurt


light blinking


If your Aircon is not cold due to Aircon blinking or malfunctioning parts. It will generally not hurt your electricity bill as your Aircon will stop functioning as the system detects an error. However, an exception to this is for a non inverter Aircon unit. If the magnetic contact malfunction. The compressor unit may continue to run even if the Aircon is turned on. Resulting in your Aircon running all the time. You will get the shock of your life when you receive your electricity bills at the end of the month.


Situations in which it will hurt your electricity bills


Insufficient Refrigerant

Insufficient Refrigerant


If you have insufficient refrigerant. The condenser unit may end up working harder to achieve a similar level of coolness to cool your room. Nonetheless insufficient refrigerant level usually will result in Aircon not cold. But the compressor will still work harder due to lower gas pressure.


Compressor Overheating


If your compressor overheats. The compressor may stop running and start running after a while. This start stop motion is similar to braking and accelerating constantly in your vehicle. The compressor will consume most energy when they are starting up. Making your Aircon system extremely inefficient.


Aircon not cold due to Dirty Evaporator Coil


If your evaporator coil or blower wheel is dirty. Your Aircon will not be blowing cold Air efficiently. Similar to insufficient gas level, your Aircon compressor will work harder in pressurizing the system. Hence resulting in higher electrical bills for you.




In conclusion, there may be many reasons why your Aircon is not cold. You can use our troubleshooting tips to find a possible cause to your Aircon not blowing cold Air. In addition, there are some situations in which it may cause you to have higher electricity bills. Therefore, it may be wise to contact an experienced Aircon company to solve this issue for you.

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