#1 Filter issues. Dirty, clogged or overly restrictive filters may be the cause of many heating-and-cooling problems, including a constantly running AC system.
Clogged or dirty air filters can severely impede airflow and reduce your AC system's efficiency. When air filters become clogged with dust, pet hair, and other debris, the unit has to work harder to circulate air, resulting in more frequent cycles.
Typically, short cycling can come from an incorrect unit size or programmable thermostat problems. However, it could also be caused by neglected routine maintenance or something that might require a simple repair.
If you have noticed that your air conditioner has been turning on and off as frequently as every 10 minutes, your system is most likely in need of repair due to “short-cycling.” Short-cycling is when a system turns on and off abruptly and often.
You May Have Thermostat Problems
If your AC goes on and off without warning, then the most likely cause if your thermostat. Your thermostat is the nerve center of your entire AC system, meaning that a faulty thermostat can prevent the whole thing from functioning.
A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.
Typical AC Cooling Cycles
An AC that works will typically perform two or three cycles an hour. On moderately hot days, your AC should typically only run for 10-15 minutes to cool your house thoroughly. This means it will often run for around 10 minutes before shutting off and then stay off for about 10 minutes.
Allowing your air conditioner to rest is an excellent way to extend its life and ensure it operates efficiently throughout the years. Air conditioners, like homeowners, require rest in order to recover and perform optimally.
An undersized air conditioning system most commonly manifests as an air conditioner that never stops running. When this occurs, cooling coil pressure will start to drop before freezing over, which could damage your AC's compressor.
Refrigerant Issues: Low refrigerant levels due to leaks can result in your AC working intermittently. A professional technician can identify and fix refrigerant problems. Electrical Problems: Loose or damaged wiring, faulty capacitors, or a malfunctioning compressor can cause your AC to behave erratically.
In some cases, an air conditioner's short cycling can be caused by something as simple as a thermostat issue. For example, if your thermostat is not calibrated correctly, it may have trouble accurately gauging your home's temperature. As a result, your AC unit may turn on and off at seemingly random times.
And, the best spot to do it at is 78 degrees Fahrenheit. According to Energy Star, it's an ideal temperature. 78 degrees keeps you fairly cool and comfortable during the day. It also shouldn't make your electric bill skyrocket.
To unclog an AC drain line, turn off the power to the unit. Locate the drain line and use a wet/dry vacuum to suck out the clog. Flush the line with water using a garden hose or cup of water. Check and clean the drain pan under the indoor unit.
How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
Got a central air conditioner that turns on and off every few seconds or minutes? This is called “short cycling” (because normally the AC has a regular on and off “cycle” that varies with the outside temperature.) Short cycling wears out the outside unit's compressor.
Determining the right hours per day your AC should run is crucial for maintaining comfort without incurring unnecessary costs. On an average summer day, a general guideline is that your AC should operate between 12 and 16 hours.
The short answer is, yes, HVAC overuse is possible and can occur. Running your AC around the clock is going to quickly increase your energy costs and your unit may also experience plenty of damage. Although it may be hot where you live all day long, you need to give your unit a rest so you can avoid it overheating.
Should I turn my AC off if it is short cycling? No, this is not necessary unless the evaporator coils are frozen, in which case, turn off your air conditioner to let the coils thaw.
The refrigerant, or Freon, levels in your system may be too low. This coolant is crucial for absorbing heat and cooling air, so when there is not enough of it, the compressor pressure levels become unstable, causing it to turn on and off repeatedly.
Central AC Short Cycling
Homeowners spend between $75 and $600 to deal with short cycling issues in their central AC systems.