If your air conditioner were to run continuously, your home would become too cold. It would use more energy and possibly cause iced up refrigerant coils. If your AC turned off too soon, it would not keep the house cool.
Your air conditioner usually switches regularly between on and off modes to control the temperature.
The AC experts at Upstate Home Maintenance Services want you to understand your AC cycle, why it’s important, and what it reveals about your air conditioner’s health.
Blog Table of Contents
What Is Cycling and Why Is It Important?
We usually describe the air conditioner turning off and on in terms of “cycling.” When an air conditioner operates smoothly, it usually switches on and turns off regularly to keep your home cool.
The AC cycle when the air conditioner is on is called the cooling cycle. An air conditioning or HVAC technician will consider the cooling cycle when diagnosing common air conditioner problems.
Running Time
Running time means how long your thermostat lets your AC run before it shuts off again. While your AC is running, a process of heat exchange will carry heat away from your home and distribute cool air to your home, reducing the indoor temperature.
Stopping Time
Stopping time refers to how long the AC unit will stay off between cycles. While your AC unit is off, temperatures inside your home will naturally rise if the air outside is warmer.
How Your Air Conditioner Regulates Temperature
A healthy air conditioner turns off and on according to a temperature sensor that monitors the temperature inside the house compared to the thermostat setting.
The AC will turn off if the inside temperature is cooler than the set temperature.
On hot days, the temperature will rise again as heat from the outside warms the air indoors, causing the air conditioner to turn on again until the temperature drops.
The Role of Cycling in How Your Air Conditioning System Works
An air conditioning system is typically more than just one device. It consists of different components, including:
- The outdoor unit, which contains the compressor and radiates warm air into the environment
- An indoor unit that has the evaporator coils
- In mini-split systems, an individual wall-mounted air conditioner unit for each room
- The ductwork in HVAC systems and pipes in mini-split systems that carry cool air
- A thermostat that regulates air conditioner cycles
A qualified technician will inspect every part of air conditioning systems when diagnosing problems.
How Long Should Air Conditioner Cycles Be?
How long should an air conditioner run during the cooling cycle?
For a properly operating air conditioner system, cooling cycles should occur no more than two or three times per hour and last for no more than 15 or 20 minutes in one cycle.
How long a healthy air conditioner runs during the cooling cycle depends on the outside temperature and the temperature settings.
On extremely hot days, the thermostat will make the AC stay on longer because long cycles allow the AC to carry more heat from your home and release it outside.
On warm days, the air conditioner cycle does not need to be as long unless the thermostat is set for a very low temperature. Setting the temperature too low is not good for air conditioners and can increase your utility bills.
Understanding Long and Short Cycling
Short Cycling
A short cycle occurs when air conditioners turn off after less than 15 minutes and stays off for a longer time between cooling cycles.
When your air conditioner runs for a shorter period than normal, it can indicate:
- An oversized ac that is too powerful for the home cools the air too quickly
- The compressor shuts down early because of an electrical problem, causing a short cycle
- Dirty filters prevent the AC from getting enough airflow, causing it to stop
To avoid short cycles, have an air conditioning technician put in a fresh filter and check the electrical systems for any problems.
Long Cycling
When air conditioners remain running longer than 15 minutes and stay off for less than ten minutes, it could be a sign that they are struggling to maintain the set temperature.
The reasons for a long cycle include:
- The thermostat is set at too low a temperature on a very hot day
- The temperature sensor is not reading the temperature correctly
- A refrigerant leak, leading to low refrigerant levels
- Dirty coils make it difficult for the ac system to radiate heat
- A clogged or dirty filter prevent the ac system from distributing cold air effectively
- Frozen coils prevent the air conditioner from extracting heat from your home
- Your AC is undersized for your home.
Have your technician check for signs of leaking refrigerant and low refrigerant levels. Ask them to recalibrate the thermostat and clean or replace the air filter.
Tell them about the problems you have been having with long or short cycles.
Do I Need Air Conditioner Servicing?
While your air conditioner should run for between 15 minutes and 20 minutes per cycle, short or long cycles do not necessarily mean that your air conditioner needs servicing.
Should your air conditioner stay on for too long, check the thermostat setting. Set it to a higher temperature and see if the cycle length shortens compared to the previous cycle.
If changing the thermostat settings doesn’t fix your AC cycles, call in a professional.
Even if you don’t have a problem with long or short cycling, it is a good idea to have a professional inspect and maintain your AC system once a year, ideally in the spring.
Call Upstate Home Maintenance Services Today
Contact us at Upstate Home Maintenance Services if you have problems with short cycling if cycles run longer than they should, or your air conditioning tends to run longer than it should in each cycle.
Call (864) 529-7310 for our Spartanburg, SC, location and (864) 210-8444 for Greenville, SC. We’ll check your filters, thermostat, heat exchange system, coils, and other parts of your air conditioning system to fix common problems like short and long cycles.
This article was written by Morgan Loch
Owner of Upstate Home Maintenance Services LLC and Local HVAC Guru
