Short-cycling is a pretty common problem in many modern air conditioning systems. The exact nature of this problem is hard to explain in a few sentences because short-cycling can be the cause and the symptom of the problem at the same time! This may sound confusing, but in certain cases, these problems can be solved with some simple adjustments. Attempting to correct short-cycling without formal training is not possible most of the time because there are root causes to fix first. In this article, we will take a more in-depth look at short cycling, covering the causes, the effects, and how you can correct the problem.
Is Short-Cycling a Serious Problem?
The short answer is yes. When your air conditioner is short-cycling, it will turn on and off again rapidly. This may not sound too serious, but that fast action can actually damage your cooling equipment. The components are placed under extra strain and that makes them more prone to failure. Many AC system components cannot be repaired and a replacement can be expensive. In fact, an AC system that is behaving in this way is likely to have a lower than expected lifespan. Replacing your AC system earlier is a cost that most people want to avoid and it costs a lot of money in the medium to long term.
Another problem related to short-cycling are the inflated energy bills due to inefficiency. When the AC system is turning on and off again, it can use up more energy with no gain in performance which is simply a waste of money.
What is Short-Cycling?
We briefly covered this above, short-cycling is the rapid on and off behavior present in some AC systems. The system is turning off before a complete cooling cycle has finished and that is a bad situation. An AC system that is working optimally will power the compressor unit and run it until the desired temperature on the thermostat is reached. The system will then turn off the compressor until there is a need for additional cooling.
When the AC system is short-cycling, the compressor is turned off before the cooling cycle is complete. Then shortly after it turns back on again to start a new cooling cycle, which will be turned off again, and this behavior repeats. In fact, this process can occur many times in a single hour and it’s a sure sign that you have a serious problem. There are a number of reasons why short-cycling may be happening. Let’s take a look at these potential causes in a little more detail.
An Incorrectly Sized AC System
Before an AC system is installed a professional load calculation is needed to assess the size of system needed to cool the home. There are simple online tools that you can use for free, but they are not accurate and they are entirely based on the square footage. In reality, there are other factors that can affect the size of the AC system that you need, including the number of windows, insulation levels, home orientation, and more. A load calculation is complex, it should be carried out by a local certified and licensed HVAC specialist.
A Clogged Air Filter
The AC system relies on a constant airflow to work correctly and if the air is impeded by a clogged air filter, it’s a problem. When the airflow is restricted, it causes the equipment to work harder, which can result in short-cycling and failures. This is the easiest problem to solve and you don’t need any specialized HVAC training. The full instructions on how to change the air filter should be detailed in your owner’s manual. Cleaning or replacing the air filter should be carried out to the frequency stated in your manual. But, if you have pets that shed a lot of hair, you may want to consider more frequent air filter changes.
A Miscalibrated Thermostat
If your thermostat is miscalibrated or it has developed a fault, it can result in short-cycling problems. After all, the thermostat is the entire brain of your AC system. If the thermostat is sending the wrong demands for cooling it can confuse the system.
A Lack of Refrigerant
Many people think that their AC system cools their home, but this is a side effect of the process. A more accurate way to describe air conditioning is that it removes heat from the home. This is achieved with refrigerant that is kept under pressure and cycled through your home. As the refrigerant changes state from a liquid to gas and back again it absorbs the heat and moves it outdoors. If there is a refrigerant leak, the pressure will drop and the AC system will lose efficiency. This will result in a lack of performance and short-cycling can occur. Recharging the AC system should be left to a heating and cooling specialist. Mixing together different types of refrigerant can affect the efficiency and the process can be tricky if you don’t have any experience.
Leaky Ductwork
The ductwork distributes the treated air throughout your home and if there are leaks this air is lost. This will affect the efficiency because you will be paying for air that you are not receiving. Most people attempt to compensate for this lack of performance by running the system for longer, which increases the energy bills. When air escapes it can also lead to short-cycling because the sensors on the thermostat will not have an accurate reading on the real temperature in your home.
In Conclusion
As you can see, short-cycling can be a significant problem for your home cooling. If the AC system is too small for your home, it will run constantly and your desired temperature will never be reached. If the system is too large, it will cool the space too quickly before the cycle is completed. Changing a dirty air filter is easy, but recharging refrigerant is best left to a professional. If you have leaky ductwork, it can be hard to locate the leak and a fix with duct tape is a temporary measure at best. If you have short-cycling problems that cannot be fixed with an air filter change, it’s time to contact your local heating and cooling specialist.