Central air conditioning is a pleasure for homeowners during the hot summer months, but it can also be a big expense. An air conditioner that runs constantly is using more energy unnecessarily. Finding the cause is important for both your comfort and your wallet.
Here are some of the common issues that cause an air conditioner to run excessively.
Improper size and installation (including wrong duct size)
When it comes to air conditioners, bigger is not always better and smaller is not always less expensive. A unit that is too big will not be able to remove the moisture from the air effectively and, as a result, will have shorter run times while using excessive amounts of electricity. A unit that is too small will have to work harder to cool your home, increasing wear and tear without reaching the desired coolness. For optimal performance, the system must be sized correctly. That said, a properly sized, efficient air conditioner is designed to run continuously in order to maintain the desired temperature, but will do so with maximum efficiency and minimum wear and tear.
The ductwork must also be sized relative to the unit in order to properly distribute the air throughout your home for comfort and efficiency.
Dirty or restrictive air filter
The air filter should be changed regularly (every one to three months for a standard one- to two-inch filter) in order to protect your HVAC system and keep it working properly. A clogged filter blocks airflow, causing the system to work harder. To achieve the desired temperature, that can mean running more often. All that extra work can lead to breakdowns and premature replacement, as well as higher energy bills and less comfort.
Dirt and debris, such as leaves, grass clippings and mud, that collects on the evaporator or condenser coils can diminish the performance of your air conditioner. Condenser coils are exposed to the elements and need to be cleaned. Periodically, turn off the electrical power to the system and hose down the unit.
The evaporator coils are continually exposed to airflow circulated by the blower and can build up dust and dirt. A layer of dirt on the surface of the coils can affect their ability to transfer heat from the air to the refrigerant, causing longer “on” cycles. A visual inspection of the evaporator coils can determine if they are in need of maintenance.
Blower motor and fan issues
One possibility is that the fan speed needs to be adjusted. If, however, your air conditioner is older, the blower motor and other mechanical components may be showing signs of wear. At 15 years, the system is nearing time for replacement. Age and wear are two contributors to decreased performance and could be the reason your system runs more often.
The issue may not be with the air conditioner itself, but with the thermostat. A faulty thermostat prevents the system from turning off once the desired temperature is reached. Compare the actual temperature in the room to the thermostat setting. If it is lower, then the thermostat likely needs to be replaced.
Air leaks or poor insulation
Leaks in the air ducts allow the cooled air to escape before reaching the rooms of your home, so even though the air conditioner is working, the living spaces are not reaching the correct temperature and the system keeps running. Poor insulation and air leaks around doors and windows can have the same effect.
Lack of maintenance
Most problems can be easily resolved — and prevented — with proper maintenance. A professional technician will thoroughly examine and clean the system, as well as correct any issues before they turn into costly repairs. Foregoing annual maintenance can lead to airflow problems and inefficient cycling, and may also void your warranty.