AC Blowing Warm Air In House: 8 Possible Reasons & Solutions

AC Blowing Warm Air In House 8 Possible Reasons & Solutions

Anthony Barnes

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Air conditioning is a fantastic addition to your home, but it can also be an expensive one.

When you need to cool down the house, you may find yourself looking for ways to save money on air conditioner repair bills.

Why Might You Want Air Con In Your Home?

AC Blowing Warm Air In House: 8 Possible Reasons & Solutions

The first thing that comes to mind when we think of air conditioning is that it helps us keep our homes comfortable in hot weather.

But did you know that there are other benefits to having an AC system? 

Here are some reasons why you should consider installing an AC unit in your home.

  • Energy Savings. The most obvious benefit of having an air conditioning system is energy savings. When you have an AC system installed, you will not need to run your heater or air conditioner as often. 

This means you will use less electricity and gas. You will also reduce your heating costs by using your AC instead of relying on your furnace.

  • Health Benefits. An air conditioning system has many health benefits. It reduces the number of dust particles in the air. Dust particles cause respiratory problems such as asthma attacks. By keeping the air clean with an AC system, you will help prevent these problems from occurring.
  • Increased Home Value. If you want to sell your home, you will definitely want to make sure it is well-maintained. One way to do this is to install an air conditioning system. A properly maintained AC system will increase the value of your home because potential buyers will see that you took good care of your property.
  • Improved Indoor Air Quality. Your indoor air quality is important to your overall health. Poor indoor air quality can lead to headaches, coughing, sore throats, sinus infections, and even asthma attacks. Having an AC system installed will improve the quality of your indoor air.
  • Reduced Noise Level. Your neighbors will thank you if you install an air conditioning system in your home. They will appreciate the fact that they no longer hear your noisy air conditioner running all day long.
  • Lower Utility Bills. Installing an air conditioning system in the summertime can cut your utility bill significantly. You will only need to pay for the cost of electricity needed to operate the compressor.
  • Better Comfort. Most people enjoy being able to sleep comfortably at night. However, sleeping without air conditioning can become uncomfortable after a while. With an AC system, you can rest peacefully knowing that the temperature inside your room is just right.

AC Blowing Warm Air In House: 8 Possible Reasons & Solutions

AC Blowing Warm Air In House: 8 Possible Reasons & Solutions

While AC can be a great addition to your home, there are also times when it can go wrong – and one of the most common problems reported by homeowners is having the AC blow warm air, rather than a cool, fresh breeze.

If your AC is blowing warm air, there could be a number of reasons for this, and we will explore these, and possible solutions, in greater detail below.

1. A Dirty Air Filter

The filter located in the back of the evaporator coil needs to be cleaned regularly so that it does its job effectively.

If the filter becomes dirty over time, then the air passing through it will pick up moisture, which will result in warmer air coming out of the vents.

This problem can occur if you don’t change the filter every month, or if you leave the filter in place too long before cleaning it.

To check whether your filter needs changing, look at the bottom of the unit near the condensing coils.

There should be a small hole where the filter goes into the unit. Remove the cover plate on the top of the unit, and gently lift off the filter.

This should reveal any dirt and debris that may have accumulated within the filter. 

Cleaning the filter is very easy; simply use a vacuum cleaner to remove any dirt and debris.

The best method is to turn the machine on, hold the nozzle close to the filter, and suck away any dust and debris.

2. An Overloaded Evaporator Coil

An overloaded evaporator coil can cause the same problem as a dirty filter.

When the evaporation process takes place, heat energy is released from the water molecules.

As the water vapor rises through the ductwork, it releases some of its heat energy as it passes through the cooling fins attached to the evaporator coil.

When the evaporator coil gets hot, it begins to release more heat energy.

Eventually, the heat energy released by the evaporator coil exceeds what can be absorbed by the refrigerant flowing through the system.

At this point, the excess heat energy must escape somewhere else, and this usually happens via the vent pipe.

To fix this, you’ll need to replace the evaporator coil with a new one.

It’s important that you get a high-quality replacement coil because they tend to last longer than standard ones.

3. A Broken Condenser Fan Motor

When the fan motor fails, the condensation process cannot take place properly.

As a result, the condensate (water) builds up in the condenser coil and eventually overflows onto the outside of the condenser coil.

Repairing a broken condenser fan motor is not difficult. All you need to do is carefully unscrew the old fan motor, and install the new one.

Make sure that the blades of the new fan motor are facing towards the inside of the condenser coil, so that the condensate flows directly into the drain pan.

4. A Faulty Compressor

Faulty compressors often fail because they get clogged with lint. Lint blocks the flow of oil through the compressor, causing it to seize up.

Once this occurs, the compressor won’t start again until the blockage has been removed.

To fix a faulty compressor, first, make sure that all the electrical connections are secure. 

Then, turn the power switch on for about 10 seconds. You should hear the compressor whirring.

Next, disconnect the power cord from the wall socket, and reconnect it to the compressor. 

Finally, wait another 10 minutes, then try turning the power switch back on.

If the compressor doesn’t start, then there’s probably something wrong with the compressor itself.

To find out what’s going on, call an HVAC technician.

If the compressor motor starts but doesn’t run smoothly, or if the compressor runs too loudly, then the most likely reason is that the compressor motor is dirty.

Dirt accumulates on the stator windings, which causes them to short circuit. To clean the stator windings of a noisy compressor, follow these steps:

  • Turn the power switch on for 30 seconds.
  • Disconnect the power cord from the outlet.
  • Unscrew the cover plate from the compressor’s front panel.
  • Remove the two screws holding the top cover plate in place.
  • Carefully remove the top cover plate.
  • Using compressed air, blow any dirt off the stator windings.
  • Replace the top cover plate. Tighten the screws.
  • Reconnect the power cord to the outlet. Wait 5 minutes, then turn the power switch on.
  • Try running the compressor for at least 15 minutes. If it still isn’t working, then call an HVAC professional.
  • If the compressor does not work after cleaning the stator windings as described above, then the next step will involve replacing the compressor’s impeller. This can be done by removing the three bolts holding the impeller in place. Be careful when you’re doing this; you don’t want to damage the impeller.
  • After the impeller has been replaced, reassemble the compressor.
  • Check the compressor once more for leaks. If everything looks good, then turn the power back on.
  • If the compressor still doesn’t work, then call an HVAC technician.
  • If the compressor works fine, then check the filter. The filter should be changed every six months, depending on how dusty your home is.

5. A Defective Thermostat

Defective thermostats can lead to overheating of the evaporator coil.

If the temperature inside the house rises above the setpoint, the thermostat will shut down the airflow through the evaporator coil.

This causes the evaporator coil to become even hotter, which results in additional heat being released.

The solution for a defective thermostat is simple: if all else fails, you will need to just replace the thermostat.

However, before you do so, it is important to make sure that the thermostat is turned on, and to try resetting it to see if this brings you any success. 

Resetting the thermostat involves pressing the “reset” button located near the thermostat’s faceplate.

Once the thermostat has been reset, press the “on” button until the unit turns on. If all this fails, you may need to invest in a new thermostat.

6. An Overloaded Compressor Motor

An overloaded compressor motor could cause the compressor to overheat.

When this happens, the compressor won’t operate properly. As a result, the compressor will have to work harder than it needs to, which means that it will consume more energy.

To determine whether or not your compressor is operating correctly, try turning the power switch on and off several times while listening to the compressor.

If the noise level increases each time you turn the power switch on, then you know that there is something wrong with the compressor.

If the noise level stays constant regardless of how many times you turn the power switch off and on, then you need to contact an HVAC technician to help you diagnose the problem.

7. Dirty Condenser Coil

If the condenser coil becomes dirty, it will reduce its ability to transfer heat from the air outside the house into the air inside the house.

This will cause the indoor temperature to rise, which leads to higher utility bills.

A dirty condenser coil can be cleaned using a garden hose. First, spray water onto the condenser coil, and allow it to run for about five minutes.

Then, use a vacuum cleaner to remove the excess water. You may also want to consider having a professional clean your condenser coil.

8. Leaking Refrigerant Lines

Refrigerant lines are responsible for transferring refrigerant from the compressor to the condenser coil.

They are made up of copper tubing. If these lines leak, they will release refrigerant into the atmosphere.

This can happen when the refrigerant expands as it travels through the system. It expands because the pressure inside the system drops.

The drop in pressure allows some of the gas to escape. Leakage occurs most often at joints between different pieces of pipe.

These joints should be tightened every year.

Tackling leaking refrigerant lines is easy; you simply need to tighten them by hand. To do this, first, disconnect the old pipes from the new ones.

Then, slide the new pipes onto the old ones. Finally, tighten the joint between the two pieces of pipe using pliers.

Maintaining Your Air Conditioning Unit

AC Blowing Warm Air In House: 8 Possible Reasons & Solutions

In order to keep your air conditioning unit in the best possible condition, it is important that you maintain it regularly and correctly.

Here are some things that you need to remember as part of regular maintenance:

1. Clean The Filter Regularly

The filter is one of the most important parts of your air conditioning unit.

A dirty filter will lead to increased electricity consumption and lower efficiency.

You should change your filter once per month. Make sure that you replace the filter before it gets clogged.

2. Check The Drain Line

When you check the drain line, make sure that it doesn’t become blocked.

If it does get blocked, it will prevent any liquid from flowing out of the system.

3. Change The Oil

Changing the oil in your air conditioning unit is another way to ensure that it operates efficiently.

Changing the oil helps to lubricate moving parts so that they don’t wear down prematurely.

4. Inspect The Compressor

An inspection of the compressor is necessary if you notice any unusual noises coming from it.

An inspection will also reveal whether or not the compressor has been damaged.

5. Check The Electrical Wiring

Checking the electrical wiring is another thing that you should do regularly.

Doing so ensures that there are no loose connections or worn wires.

6. Replace The Thermostat

Replacing the thermostat is another task that you should perform on a regular basis.

If you have an older model, then you might want to replace it with a newer one.

7. Check the Hoses

If your hoses start to look dry or cracked, then you should replace them.

This is especially true if they are located near areas where moisture collects.

8. Check The Freon Levels

If the freon levels in your air conditioning unit are low, then you should add more to the system.

You can use a test kit to measure the amount of freon in your system.

9. Perform Maintenance Checks

Performing maintenance checks on your air conditioning unit is something that you should do regularly as well.

Checking the filters, checking the drain line, inspecting the compressor, changing the oil, etc., are all tasks that you should perform on an annual basis.

10. Have Your System Serviced

Having your air conditioning unit serviced is another step that you should take.

Having your system serviced ensures that it runs at peak performance.

11. Maintain Proper Temperatures

Keeping proper temperatures inside your home is another important aspect of maintaining your air conditioning unit.

If the temperature inside your house is too high, then you may end up having to run your AC for longer periods of time.

Final Thoughts

Your air conditioning unit can be a great addition to your home and, depending on the climate, is often a necessity. 

By taking good care of it, including regular servicing and maintenance, and by having a good understanding of the reasons that issues may arise, you can enjoy your unit for longer, and ensure that your home is cool and comfortable all year round!

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By Anthony Barnes

Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age