# Why does my air conditioner keep turning on and off? 1. [Home](https://arlite.co/) 2. [Support](https://arlite.co/support/) 3. [Air conditioning](https://arlite.co/support/air-conditioning/) 4. Why does my air conditioner keep turning on and off? **Browse support** [Support home](https://arlite.co/support/) [Solar](https://arlite.co/support/solar/)[View all](https://arlite.co/support/solar/) - [How does a solar power system work in a Brisbane home?](https://arlite.co/support/solar/how-does-a-solar-power-system-work-in-a-brisbane-home/) - [How do I turn off a solar inverter safely?](https://arlite.co/support/solar/turn-off-solar-inverter-safely/) - [Do solar panels work during a blackout?](https://arlite.co/support/solar/solar-during-power-outage/) - [Can I add a battery to my existing solar system?](https://arlite.co/support/solar/add-battery-to-existing-solar-system/) - [Hail or storm damage to solar panels: what to do](https://arlite.co/support/solar/hail-storm-damaged-solar-panels-what-to-do/) [Air conditioning](https://arlite.co/support/air-conditioning/)[View all](https://arlite.co/support/air-conditioning/) - [Why does my air conditioner keep turning on and off?](https://arlite.co/support/air-conditioning/air-conditioner-turning-on-and-off/) - [Why is my air conditioner not cooling or heating properly?](https://arlite.co/support/air-conditioning/air-conditioner-not-cooling-or-heating/) - [Why is my air conditioner leaking water inside?](https://arlite.co/support/air-conditioning/air-conditioner-leaking-water-inside/) - [Why does my air conditioner smell musty or like dirty socks?](https://arlite.co/support/air-conditioning/air-conditioner-smells-musty-dirty-socks/) - [Can solar panels run my air conditioner at night?](https://arlite.co/support/air-conditioning/can-solar-panels-run-my-air-conditioner/) [Electrical](https://arlite.co/support/electrical/)[View all](https://arlite.co/support/electrical/) - [Why does my circuit breaker keep tripping?](https://arlite.co/support/electrical/circuit-breaker-keeps-tripping/) - [Why does my safety switch keep tripping?](https://arlite.co/support/electrical/safety-switch-keeps-tripping/) - [Burning smell or hot power point: what to do right now](https://arlite.co/support/electrical/burning-smell-hot-power-point/) - [Why is there no hot water? Electrical faults explained](https://arlite.co/support/electrical/no-hot-water-electrical-checks/) - [What smoke alarms does Queensland require?](https://arlite.co/support/electrical/queensland-smoke-alarm-requirements/) [Costs and finance](https://arlite.co/support/costs-and-finance/)[View all](https://arlite.co/support/costs-and-finance/) - [How does interest-free finance work for home energy upgrades?](https://arlite.co/support/costs-and-finance/interest-free-finance-home-energy-upgrades/) - [What affects the cost of a home battery in Brisbane?](https://arlite.co/support/costs-and-finance/what-affects-home-battery-cost-brisbane/) - [Can I get compensation for a power outage in Queensland?](https://arlite.co/support/costs-and-finance/power-outage-compensation-energex/) - [How much does an electrician cost per hour in Brisbane?](https://arlite.co/support/costs-and-finance/electrician-cost-brisbane/) - [What affects switchboard upgrade cost?](https://arlite.co/support/costs-and-finance/switchboard-upgrade-cost/) [Air conditioning](https://arlite.co/support/air-conditioning/) An air conditioner that starts and stops repeatedly, called short cycling, often comes from sizing, airflow or a fault, and needs a technician. By Casey Midgley, Arlite Energy Last reviewed 30 October 2026 4 minute read **No DIY.** Electrical work must be done by a licensed electrician. Never open, repair, test or modify electrical equipment yourself, even if it looks simple. This guide explains what is happening; it is not a how-to. **On this page** 1. What is short cycling? 2. Why does it happen? 3. Is it harmful? 4. Could the settings be the cause? 5. Could the unit be the wrong size? 6. Is this something a service will fix? 7. What to note before you call 8. What happens on the visit? 9. Why does the pattern matter? 10. Frequently asked questions An air conditioner that turns on and off every few minutes is short cycling. Common causes are a unit that is too big for the room, restricted airflow, a low refrigerant charge, or a sensor or electrical fault. It wastes energy and wears the unit, so have a licensed technician look at it. ## What is short cycling? A normal system runs for a decent stretch to reach the set temperature, then rests. Short cycling is when it starts, runs briefly and stops again, over and over. Many modern inverter units (units that adjust their speed rather than switching fully on and off) are designed to run steadily, so frequent stop-start behaviour stands out. ## Why does it happen? - **An oversized unit.** A unit that is too powerful for the room cools it very quickly and then shuts off. Consumer guides such as Choice note that an oversized unit runs in frequent short cycles and can dehumidify poorly. - **Restricted airflow.** Dust build-up or blocked vents can cause the unit to overheat or ice up and shut down to protect itself. - **A low refrigerant charge.** This makes the system work harder and trip its protection. - **A faulty sensor or thermostat.** If the unit reads the room temperature wrongly, it may stop and start early. - **Electrical or control faults.** A failing part can cause the unit to cut out. - **Placement.** A remote or sensor in direct sun or near a heat source can mislead the unit. ## Is it harmful? Frequent starts put stress on the compressor, the heart of the system, and can lead to higher power use and shorter equipment life. It can also leave a room humid and uncomfortable because the air is not being dried properly. Stop and get help If the cycling comes with a burning smell, smoke, sparks, noises or tripping power, stop using the unit and keep clear. Leave the building and call 000 for fire, smoke or sparks. For cycling alone, contact an ARC-licensed air-conditioning technician; a licensed electrician may also be needed if power supply is involved. ## Could the settings be the cause? Using the remote or app as normal, check that the mode and temperature are sensible. Setting the temperature very close to the room temperature, or switching modes repeatedly, can make the unit appear to cycle. If the settings are right and it still cycles, a fault is more likely. ## Could the unit be the wrong size? Yes, and this is common when a system was chosen without a proper assessment. Room size, ceiling height, sun exposure, insulation and layout all affect the right size. A licensed professional can assess this properly. Our guide on sizing an air conditioner explains the factors. ## Is this something a service will fix? Sometimes. A technician can find out whether the cause is airflow, a sensor, refrigerant, electrical or sizing, and advise on the best response. ## What to note before you call 1. Time the cycles — Note roughly how long it runs and how long it rests, and whether this is the same all day. 2. Record the conditions — Write down the mode, the temperature set, the weather and which room is affected. 3. Photograph the labels and display — Capture the make and model label and any lights or codes on the display, without touching or opening anything. What you can safely check Watch the unit from a distance and note how often it starts and stops. Photograph the display and read the manual. Do not touch or open the unit. ### What happens on the visit? A licensed technician will check airflow, sensors, controls, refrigerant and electrical operation, and compare the system with the room it serves. ### Why does the pattern matter? Technicians can learn a lot from how the unit behaves, such as whether it cuts out quickly after starting, after several minutes, or only in certain weather. A few notes from you can point them towards airflow, sensors, refrigerant, power supply or sizing much faster. ## Frequently asked questions - It is when an air conditioner starts, runs for a very short time, then stops, and repeats this over and over. - Not always. A unit that is too large can short cycle and handle humidity poorly, so the right size matters. - Some cycling is normal when the room reaches the set temperature. Constant, rapid cycling is not. - It tends to, because starting the compressor takes extra effort and the unit works less efficiently. [Learn about Air Conditioning](https://arlite.co/services/air-conditioning/) Related services: [Ducted Air Conditioning](https://arlite.co/services/air-conditioning/ducted-air-conditioning/) ## Official guidance For the rules and safety information that apply to your home, go to the regulators and industry bodies directly. - [Australian Refrigeration Council](https://www.arctick.org/) - [Energy Rating (Australian Government)](https://www.energyrating.gov.au/) - [Electrical Safety Office Queensland](https://www.electricalsafety.qld.gov.au/) Was this helpful? Written by the team at Arlite Energy, a Brisbane business that designs and installs solar, air conditioning and electrical work for homes and businesses. We write these guides in plain English so you know what is happening in your home. ## Related articles - [Air conditioningWhat size air conditioner do I need for my room or home?The right kW size depends on room size, ceiling height, sun, insulation and layout, so a licensed professional should assess it.](https://arlite.co/support/air-conditioning/what-size-air-conditioner-do-i-need/) - [Air conditioningWhy is my air conditioner not cooling or heating properly?Weak cooling or heating usually comes from airflow, settings, sizing or refrigerant problems, and some of these need a licensed technician.](https://arlite.co/support/air-conditioning/air-conditioner-not-cooling-or-heating/) - [Air conditioningWhy does my air conditioner keep tripping the breaker?An air conditioner that trips the breaker or safety switch has an overload or fault that a licensed electrician needs to find.](https://arlite.co/support/air-conditioning/air-conditioner-tripping-breaker-safety-switch/) - [Air conditioningWhy is there ice or frost on my air conditioner?Some frost on an outdoor unit in heating mode is normal, but ice on an indoor unit or on a unit in cooling mode points to a fault.](https://arlite.co/support/air-conditioning/ice-frost-on-air-conditioner/) ## Still stuck? Tell us what is going on and we can arrange a call-out. [Book a call-out](https://arlite.co/contact/) On this page 1. What is short cycling? 2. Why does it happen? 3. Is it harmful? 4. Could the settings be the cause? 5. Could the unit be the wrong size? 6. Is this something a service will fix? 7. What to note before you call 8. What happens on the visit? 9. Why does the pattern matter? 10. Frequently asked questions --- **Arlite Energy**, Unit 1, 1468 Anzac Avenue, Kallangur QLD 4503. Phone [(07) 3062 9299](tel:+61730629299), email [info@arlite.co](mailto:info@arlite.co). Monday to Friday, 7am to 5pm. Page: https://arlite.co/support/air-conditioning/air-conditioner-turning-on-and-off/ Site index for agents: [llms.txt](https://arlite.co/llms.txt), [sitemap](https://arlite.co/wp-sitemap.xml), [developer resources](https://arlite.co/developers/).