Air conditioning always works best when the outdoor temperature isn’t all that much higher than your desired indoor temperature. When the temperature outside is in the low 80s, your AC system should have no issues keeping your home cool. In this situation, your AC will typically only ever need to run for around 15 minutes at a time and will usually only run twice an hour. When the outdoor temperature rises into the upper 90s or 100s, most AC systems will start to struggle and work much harder than normal. To understand why this is, today we’re going to discuss the ways that extreme heat affects your home and your AC system and also what steps you can take to protect your system against potential damage.
How High Temperatures Affect Heat Gain in the Home
There are a few different reasons that extreme heat puts additional strain on an AC system. The first is simply because high temperatures will cause the indoor temperature to rise and the home to become hotter more quickly. Sunlight beaming in through windows on overly hot days leads to lots of heat gain. If the home’s exterior structure isn’t tightly sealed and well insulated, lots of hot air will also leak inside the home making the indoor temperature rise even more. All of this heat coming inside will often result in the AC only ever remaining off for a few minutes before the indoor temperature rises to the point that the thermostat signals the system to turn on again.
How the AC Heat Transfer Process Works
The bigger issue in extreme heat is that it becomes far more difficult for the outdoor AC condenser unit to release all of the heat that the system removed from inside the home. Air conditioning works through a heat transfer process that relies on a heat exchanger inside the home and another heat exchanger in the outdoor AC unit. The evaporator coil inside the home removes heat from the indoor air using cold refrigerant. This process results in the warm air blowing over the evaporator coil becoming cooler while at the same time increasing the temperature of the refrigerant.
The refrigerant then transports all of the heat the system removed from the home back outside. When the refrigerant enters the outdoor unit, it passes through the compressor. When the refrigerant is compressed, the pressure instantly becomes much higher and the refrigerant is super-heated and instantly transforms into an extremely hot gas.
The refrigerant then flows into the condenser coil, which works in tandem with the fan in the outdoor unit to release all of the heat into the air outside. In milder weather, this process works smoothly and all of the heat can easily be released. This is simply because the refrigerant is so much hotter than the outdoor air so all of the heat quickly flows out of the refrigerant into the air.
How Extreme Heat Impacts Performance and Can Damage an AC System
Whenever the outdoor temperature rises into the mid-90s or above, it becomes much more difficult for the system to release all of the heat. The heat transfer process works much more effectively and more quickly whenever the difference between the refrigerant temperature and the air temperature is much greater. Even in extreme heat, the refrigerant will be hotter than the air temperature when it first flows into the condenser coil because it was super-heated by the compressor. The issue is that the refrigerant will quickly cool down to the air temperature as it releases heat, which results in no more heat being able to flow out of the refrigerant into the air.
When the outdoor temperature is much hotter, the refrigerant will always stay at a higher temperature and a higher pressure simply because it can’t release all of the heat it absorbed from the home into the outside air. If the refrigerant is hotter than normal when it flows back inside, the AC system will cool much more slowly since the warmer refrigerant can’t absorb as much heat. This starts to put additional pressure on the system and leads to greater wear and tear since the system will now need to run longer since it takes much more time to fully cool the home.
The biggest issue with extreme is that the high refrigerant pressure makes it more difficult for the outdoor unit to pump the refrigerant through the system, which leads to increased strain on the system and can potentially cause the unit to start overheating. The compressor motor will start to get much hotter whenever the unit has to work harder, which can potentially result in the oil within the motor starting to burn. Burnt oil can’t keep the motor properly lubricated, and the motor may start to seize up if there isn’t sufficient lubrication.
This is a major issue as the compressor motor is sealed and cannot be serviced or repaired in the field. As such, the only option if the compressor motor seizes up is to have it replaced. Replacing a compressor motor is something that is rarely ever done because it is extremely expensive, which means it is usually more cost effective to simply replace the entire AC condenser unit instead.
How to Protect Your AC Against Damage in Extreme Heat
One of the biggest keys to protecting an AC system in extreme heat is to make sure that the outdoor unit has sufficient airflow. This ensures that the refrigerant can release the heat into the air more quickly and more efficiently to prevent the refrigerant pressure from being too high. The best way to ensure that the outdoor unit has proper airflow is to make sure that there is at least two to three feet of space around the front and sides of the unit so that the fan can effectively draw air through the unit. It is also important to make sure that there are no leaves and debris clogging the unit as this will also decrease the airflow.
The other essential thing is to make sure that the condenser coil is clean and not coated in dirt and dust. If the condenser coil is dirty, it will be insulated from the air flowing through the unit. This makes it nearly impossible for all of the heat to flow out of the refrigerant resulting in high refrigerant temperature and pressure, which can again cause the compressor motor to overheat and possibly seize up. This potential issue is one reason why it is important to have your AC system professionally maintained every year as the technician will ensure that the unit isn’t clogged and also fully clean the condenser coil so the heat transfer process works more effectively.
It is also important that you have sufficient airflow inside the home. If you have lots of vents that are closed, obstructed by furniture or other objects or clogged with dirt and hair, the airflow through the system will be greatly restricted. The same will also happen if the AC air filter is too dirty. When the airflow is restricted, it will again take much longer for the system to cool the home resulting in greater wear and tear and increasing the chances of the system breaking down. As such, you need to make sure all of your vents are always open, especially during times of extreme heat.
At J&W Heating and Air + Plumbing, we specialize in AC maintenance and can help ensure your system works effectively even in extreme heat. We can also repair any issues your AC might have or help if your current AC system needs to be replaced. Give us a call today for all of your AC and heating needs in Jacksonville.
