The air conditioner heat mode not working: why do you have too cold or hot air in your room?

Quite often, people encounter a problem when the air conditioner’s heat mode is not working, and they have too cold or hot air in their room. In winter, this problem is very unpleasant because the house will be cool. There are a few issues that are easy to fix.

air conditioner heat mode not working

Features of heat mode in the air conditioner

Before proceeding to the reasons for the air conditioner heat mode not working, you need to familiarize yourself with the heat mode itself. If you buy an air conditioner that will heat your home, you will notice a large number of advantages and disadvantages.

Feature benefits

The main advantages include:

  • the possibility of additional heating of the house, which provides comfort;
  • low energy costs compared to classic AC units;
  • the possibility to make not only warm air but also cold air in the room.


The shortcomings should be highlighted:

  • high price;
  • the need for additional expenses for repairs and maintenance;
  • the need for frequent maintenance.

Why does the heat mode in the air conditioner not work?

Quite often, people buy air conditioners with a heat mode; however, they do not do their job.

Because of this, you have a room with cold air.

Before starting the inspection of the main causes, it should be noted that you need to wait a few minutes for the air conditioning system to warm up.

Only then does heat begin to be released. Therefore, you need to make sure that you wait enough time. However, there are other reasons why the heating mode may not work. More about them will be discussed below.

The air conditioner heat mode not working: why do you have too cold or hot air in your room?

No heating option

Quite often, people buy an air conditioner; however, they are faced with the impossibility of heating mode. In such cases, it is appropriate to read the instruction manual. It is important to make sure that the appliance is supplemented with a reversible air conditioning system and has the necessary heat pump. The misconception is that all blocks will be identical.

Try to avoid buying a device with an indoor unit that does not have heating. Therefore, it is better to immediately clear all the information with a consultant. It is not uncommon for an icon indicating a heating option to be displayed on the remote control.

Setting the wrong settings

If you run the air conditioner in the same mode as in summer, the device will not work correctly. Heat pumps require correct settings that relevant to the issues experienced with a dehumidifier as well.

First, you need to set the “Heat” mode. Make sure that the device does not go into automatic operation mode.

Try to set a temperature that will be higher than when cooling. To save electricity, you can set 60 degrees Fahrenheit.

However, the heat pump will not start working because of this. Therefore, it is better to set the temperature to 75 degrees Fahrenheit.

Next, you need to normalize the fan speed. At the same time, be guided by your preferences. After completing these steps, the heat pump will start working. If it doesn’t, then the problem is somewhere else.

Restriction of airflow to the air conditioner

You need to make sure that air enters the device correctly. It may be necessary to move the overall furniture.

If the air conditioner is hanging on the wall, make sure the curtains are closed. If not enough air enters the air conditioner, the compressor will be overloaded and the heat pump will not start working.

Faulty circuit breaker

Air conditioners require a lot of energy. On average, the indoor unit will consume 3.5 kW per hour.

Therefore, quite often there are issues with the circuit breaker.

It is advisable to check its performance.

Problems with air filter

Often, heating problems arise if you take care of the device incorrectly. After all, due to the clogged and dirty air filter, the heat pump will not work properly. However, cleaning air conditioning filters is not difficult. There are some cleaning tips:

  • you need to vacuum the filter every month;
  • if the contamination is strong, soak the filter in soapy water. Use warm water and dishwashing detergent;
  • you can soak the filter in a solution of baking soda and warm water. This will help remove dirt and unpleasant odors;
  • dry the air filters before installation.

Do not wash the filters by placing them in the dishwasher. If the filter has been removed for washing, the working of the heat pump cannot be started.

The air conditioner heat mode not working: why do you have too cold or hot air in your room?

Switch to defrost cycle

Some devices have a defrost mode. Thanks to this, the blocks do not jam in the winter. Often the electronics fail, and the device goes into normal mode.

If you have suspicions about this issue, it makes sense to consult a specialist. He should be an air conditioner repairman.

Prevention of failure of the heating mode

Diagnosing problems with the heating mode is not difficult. However, it is better to prevent them.

Thanks to this, the device will serve for a long time, and you will not have to spend a lot of money on repairs.

Regular maintenance of air conditioning unit

You need to clean and change the filters regularly. You should also check the coils on the blocks, both from the outside and from the inside.

Check the thermostat for defects.

You also need to inspect the heat pump. Don’t forget to clean and disinfect the block that’s inside. The AC should be serviced every year. The optimal interval is 6-10 months. This ensures that the device works correctly for a long time.

It is better to clean and replace filters yourself. But entrust more serious work to professionals.

Proper use of the heat mode

To many, this recommendation seems simple. However, heat mode must be used correctly. Try to avoid overexertion.

Due to this, the heating system will start too early. The colder it is outside, the higher the temperature in the house will rise.

Do not run the device in turbo mode. You should also avoid constantly turning it on and off. This will save money on repairs, as well as on electricity.

Determination of the absence of operation of the heat mode

The easiest way to determine the inoperability of the device is to start it and wait about 1 hour.

If after this time you are still cold, then the device is not working properly.

Poor airflow quality

If bad air quality is coming out of the AC, it makes sense to check the air filter. If you see a dirty air filter that is clogged or heavily soiled, numerous problems can be encountered. If the airflow is weak, this indicates that the compressor is faulty.

In such cases, you will experience cool air in certain rooms. If there is a problem with the compressor or air duct, you have to take the device to a workshop for repair.

Presence of strange odors

Quite often, an unpleasant smell can be heard in the house. Remember that the reason may lie not only in pets but also in the heat pump. This may indicate that the wire insulation is damaged.

Because of this, unpleasant odors are formed.

If you smell moldy, it means that it has formed inside the air duct or the air conditioning unit itself. If this situation occurs, you should immediately eliminate the mold because it is dangerous to your health.

Loud noise

If you properly maintain the device and heat pumps, AC will work without noise. If you notice that the device is too loud, then there is a problem. There may be an issue with the AC fan belt.

The air conditioner heat mode not working: why do you have too cold or hot air in your room?


When people encounter the heat mode of an air conditioner, various questions may arise.

Why is my heat not turning on?

If the heat mode does not start, first check the thermostat. Its battery may have ceased to be functional, so the power is turned off.

If the thermostat is hardwired, due to a power surge or power outage, the thermostat will lose its settings. This can also happen due to a momentary power outage.

When should we use heat mode in AC?

The heat mode is the best option for winter. You can prevent drafts because there is a special fan inside. As soon as the room is at the optimum temperature, it will stop. At the same time, the room will be at a comfortable temperature if it is cold outside.

Can I use AC as a heater?

You can use the air conditioner as a heater. Almost all air conditioner heating devices have such a function, so you can heat the room as needed. In the future, you can save on heating costs and ensure optimal and comfortable warm air for yourself with such a heating mode.


As you can see, the heating function in air conditioners can fail for various reasons. Often all of them are easily solved, even on their own. If you cannot cope with the problem or are afraid to break something, you can call the wizard.

Read About How Use The Heating Mode On Air Conditioner

Robert Brooks

I have an engineering background. I have my own house, where I live with my wife and children. I want to say that the most important thing when equipping a house is to choose the right heating, ventilation, and air conditioning systems.

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