Feeling hot and sticky in the warm summer months can be unpleasant, but a constantly running air conditioner can also quickly become annoying. There are a number of reasons why an air conditioner may start to run continuously, so here we’ll explore some of the most common causes, so you can have an idea of what you need to do to correct the underlying issue.

Improper Size or Installation

The most obvious cause of a constantly running air conditioner is that it was not properly sized or installed. Although an energy efficient, correctly sized system will run almost continuously in the hot summer days to maintain your constant, desired temperature inside your home. When your system is constantly running, it may be a sign that it is was not correctly sized for your home.

Air conditioners that are too small need to work harder to maintain your desired temperature. Over time, this increases the wear and tear on the equipment, and it can compromise its lifespan. Despite the system running frequently, it will never achieve your desired comfort level. Additionally, you’re likely to experience breakdown issues. Just be aware that if your unit is too large, it can also cause issues, as the system will have shorter run times, which will increase your energy consumption. You may think that your system is frequently running, but in fact, you’re likely to simply hear it starting up and switching off frequently.

The issue may also be caused by incorrectly sized ductwork. Ductwork needs to be relative to air conditioner sizes, and if your ductwork is not, it may not be able to efficiently distribute cooled air throughout your home. This may trigger the system to run more frequently as the thermostat detects that rooms still need cooling.

Clogged Air Filter

If it’s been a while since you last changed your air filter, it is likely to be clogged and constricting the air flow. This will not only reduce the amount of cool air your system can produce, but it will also make your air conditioner run for longer and longer periods. Additionally, when a filter is clogged, the air handler needs to work harder to compensate for this, and you risk a breakdown issue developing. Dirty filters force harder working systems to overheat. Cleaning up the debris on a filter can immediately improve the airflow, and it is a good idea to replace or clean your filters every four to six weeks.

Dirty Air Conditioner Coils

Another component that can get dirty and compromise your air conditioning system performance is the coils. During an annual system check, service technicians will inspect both the condenser and evaporator coils to see if they need to be cleaned.

Condenser coils are exposed to the outdoor elements and can become clogged with garden debris and general dirt and dust. The evaporator coils are more challenging to check, but an experienced technician will be able to locate them inside your system. Since the evaporator coils are continuously exposed to airflow, they are susceptible to the accumulation of dirt and dust. When the coils become compromised, the heat transfer of the refrigerant is diminished, resulting in higher operating costs and poor cooling performance.

Faulty Thermostat

The thermostat is the brain of your HVAC system, and if your system seems to always be running, it could be an issue with your thermostat. When your home reaches the desired temperature, the thermostat may fail to register this and not trigger the system shutting off. In this scenario, the air conditioner will continue to run.

A way to check your thermostat is operating correctly is to place a thermometer near the unit. Wait an hour or two and check the readings. If the thermometer registers your desired temperature, it is your thermostat at fault.

While thermostats are generally reliable, issues can develop. Fortunately, there are some troubleshooting tips that can help you to determine if your thermostat needs attention. Firstly, be sure to check the thermostat is set for “cooling.” It can be very easy for the thermostat settings to be accidentally altered, which would prevent the system from operating correctly. Next, set the thermostat a minimum of five degrees lower and check the system comes on.

Air Leaks

Insufficient insulation or poor sealing is another common cause of constantly running air conditioners. If your home is not sealed up properly, you could be losing precious cooled air through uninsulated walls, your roof, or even small holes around your doors or windows. If your cooled air is being lost in this way, your system may struggle to achieve your desired temperature, so it will be forced to run for longer than necessary.

Your System Needs Maintenance

Another reason your air conditioner is continually running is that it needs some maintenance. Regular maintenance is crucial to keep your system running smoothly and efficiently. Ideally, your system should be checked twice a year; once in spring before the hot summer temperatures and in fall when it is no longer in use. When your system is not properly maintained, you’re likely to find your coils, ducts, filters, and other components may be compromised and fail to work efficiently.

A professional HVAC technician will inspect your system to ensure that all the components are clean and operating correctly. This servicing appointment will also provide an opportunity for preventative maintenance, to have worn parts replaced before they fail entirely and compromise performance.

You Need a Replacement

Finally, you need to think about how old your system is and whether it is time to consider a replacement. Just like every other appliance inside your home, air conditioners have a typical lifespan, and even with the proper care and maintenance, it cannot operate correctly forever.

If your air conditioner is continuously running and/or you’ve had frequent breakdown issues, you may need to consider replacing it with a new, more efficient unit. While this is an initial outlay, you’re likely to save money on your energy bills in the longer term to recoup the cost.