After noticing a notable difference in the way your home feels on a hot day, you may be wondering whether your home's central air conditioning system is starting to fail. After making sure that the thermostat is set correctly and working, you may decide to take a look at the outdoor unit.

While looking at the unit outside, there are a couple of tell-tale signs that could indicate that the unit's compressor is starting to fail. Since this vital component of the system is responsible for cooling the air, if it is starting to break down, it will be responsible for your home's lack of cool air.

1.  The Unit Vibrates and Makes a Loud Banging Noise When Starting

One sign for which you should look when determining whether the A/C unit's compressor is failing is vibrations and loud banging noises that occur when the unit starts up. Normally, the compressor will turn on smoothly when the unit kicks on.

However, if the compressor is having difficulty coming on upon demand, the force of the startup will cause vibration and banging. Known as hard-starting, this issue indicates imminent failure of the component, and it can lead to further damage if not taken care of by a professional.

2.  The Air Coming From the Exterior Vents on the A/C Unit Is Either Cool or Lukewarm

Another sign indicating a problem with the system's compressor can be determined by feeling the air coming from the outdoor unit's exterior vents. Normally, there should be hot air coming out of the vents while the compressor is cooling air passing through it and sending out the excess hot air.

However, if the compressor is breaking down, it will no longer be able to cool the air efficiently, and it will start forcing the colder air out instead of hot air. Instead, you will feel cool or lukewarm air being expelled from the unit, which almost always indicates an issue with the compressor.

If your home is not getting as cool as it should and you notice the above signs when investigating the issue, there is a good chance that the compressor is failing. If you do not have it looked at by a professional, the problem will only get worse, causing the part to fail completely and leaving you without any cool air for your house. Contact an HVAC contractor, such as A Five Star Heating & Air, in your area that offers residential AC repair services to set up a time for them to send someone to inspect the unit so that they can do what is necessary to get the system working properly.