Why Is Your Fridge Running Constantly?
A healthy fridge cycles on and off throughout the day — the compressor runs to bring the internal temperature down to the set point, then shuts off until the temperature rises enough to trigger another cooling cycle. Depending on the ambient temperature, a typical fridge runs its compressor for about 30 to 40 percent of the time. In Brisbane’s subtropical climate, that percentage is naturally higher during summer (closer to 50 percent), but the compressor should still cycle off regularly.
When your fridge runs continuously without cycling off, something is preventing it from reaching or maintaining its target temperature. The compressor keeps working because the thermostat never senses that the cabinet is cold enough. This is more than an annoyance — a constantly running compressor uses significantly more electricity, generates excess heat, and wears out faster than one that cycles normally.
The causes range from simple issues you can fix in minutes (dirty coils, a shifted thermostat dial) to component failures that need professional repair (compressor problems, refrigerant leaks). Below, we cover the most common causes we see in Brisbane homes and what you can do about each one.
Common Causes
Dirty condenser coils. The condenser coils — usually located at the back or underneath the fridge — release heat from the refrigerant into the surrounding air. When these coils are coated in dust, pet hair, and kitchen grease, they cannot dissipate heat efficiently. The compressor has to run longer and harder to achieve the same cooling effect. In Brisbane, where many homes have pets and where summer humidity causes dust to stick more readily, condenser coils can become significantly restricted within 6 to 12 months. This is the number one cause of constant running that we see, and it is the easiest to fix yourself.
Worn or damaged door seals (gaskets). The rubber seals around the fridge and freezer doors create an airtight barrier between the cold interior and the warm kitchen. When seals deteriorate — cracking, hardening, becoming misshapen, or losing their magnetic grip — warm, humid Brisbane air continuously leaks into the cabinet. The fridge detects this as a temperature rise and keeps the compressor running to compensate. You can test your seals with a simple paper test: close the door on a piece of paper and try to slide it out. If it slides easily, the seal is not gripping adequately.
Thermostat set too cold. If the thermostat dial or digital setting has been accidentally bumped to the coldest position, the fridge may struggle to reach that extreme temperature, particularly in warm weather. The recommended fridge temperature is 3 to 4 degrees Celsius, and the freezer should be around minus 18. Settings colder than this force the compressor to work longer without meaningful food safety benefit.
Faulty condenser fan. On fridges with bottom-mounted condensers, a fan blows air across the coils to aid heat dissipation. If this fan fails (seized motor, broken blade, disconnected wiring), the coils overheat even when clean, and the compressor runs continuously. You may notice the back or bottom of the fridge is unusually hot to the touch.
Faulty evaporator fan. Inside the freezer compartment, the evaporator fan circulates cold air through the fridge and freezer sections. If this fan fails, cold air is not distributed properly — the freezer may stay cold (since it is closest to the evaporator) while the fridge section warms up, causing the compressor to keep running. A telltale sign is a warm fridge but a cold freezer.
Defrost system failure. Modern frost-free fridges periodically run a defrost cycle to melt ice buildup on the evaporator coils. If the defrost timer, defrost heater, or defrost thermostat fails, ice accumulates on the evaporator until airflow is completely blocked. The fridge cannot cool properly and the compressor runs non-stop. You may hear reduced airflow from the vents inside the fridge, or see ice buildup on the back wall of the freezer.
Low refrigerant (gas leak). A refrigerant leak reduces the system’s ability to absorb and release heat. The compressor runs continuously because the reduced refrigerant charge cannot achieve adequate cooling. Signs include the fridge running constantly but not getting cold enough, frost forming unevenly on the evaporator, and the compressor running hot. Refrigerant leaks are a professional repair — topping up the gas without finding and fixing the leak is a waste of money.
Failing compressor. An ageing or failing compressor loses efficiency — it runs but does not pump refrigerant as effectively as when new. The fridge struggles to reach temperature, so the thermostat keeps the compressor engaged. A failing compressor often makes unusual noises (clicking, buzzing, or louder-than-normal humming) and the fridge may feel warmer than usual despite continuous operation.
What You Can Check Yourself
- Clean the condenser coils. Unplug the fridge. Locate the condenser coils (behind or underneath — check your manual). Use a vacuum with a brush attachment to remove dust and debris, followed by a coil brush or long-handled bottle brush for stubborn buildup. Plug the fridge back in and monitor over 24 hours.
- Check the thermostat setting. Verify the fridge is set to 3–4°C and the freezer to -18°C. If the dial was at maximum, adjust it to the middle range and allow 24 hours for the temperature to stabilise.
- Inspect door seals. Run your hand slowly around the door edge while closed — you should not feel cold air escaping. Do the paper test on all four sides of each door. If the seal is visibly cracked, warped, or does not grip the paper firmly, it needs replacing.
- Check for ice buildup. Open the freezer and look at the back wall. If you see thick ice buildup covering the vents or evaporator area, the defrost system may have failed. You can manually defrost by turning the fridge off for 24 hours with the doors open, but if the ice returns within a week, the defrost components need professional diagnosis.
- Listen to the fans. With the fridge running, listen near the back and inside the freezer. You should hear the condenser fan (near the compressor) and the evaporator fan (inside the freezer) both running. If either is silent, rattling, or grinding, it needs attention.
When to Call a Professional
If you have cleaned the coils, verified the thermostat, confirmed the seals are intact, and the fridge still runs constantly, the issue is likely a failed fan motor, defrost system component, refrigerant leak, or compressor problem. These all require professional diagnosis and repair. Do not attempt to work on the sealed refrigerant system yourself — it requires licensed equipment and handling of regulated refrigerant gases.
What the Repair Typically Involves
When we attend a fridge running constantly, we check the coils, seals, fans, and defrost system first (the most common and cost-effective fixes). We measure compressor current draw and temperatures across the system to assess overall health. Door seal replacements, fan motor swaps, and defrost component repairs are straightforward same-visit fixes on most brands.
Our standard callout is $219, which includes the first 30 minutes of labour onsite. Additional time is $45 per 15-minute block. Seniors, pensioners, and students receive a $20 discount. All parts carry a 12-month warranty. All prices are estimates only.
How Always Prompt Repairs Can Help
We repair fridges from all major brands — LG, Westinghouse, Hisense, Samsung, Fisher & Paykel, Liebherr, and more. Our technicians carry common parts including fan motors, thermostats, door seals, and defrost components on every van.
We service all of Greater Brisbane from our Underwood workshop — CBD, southside, northside, east to Cleveland, west to Ipswich, and south to the Northern Gold Coast. Six vans, same-day or next-day service in most cases.
Book your fridge repair online at alwayspromptrepairs.com.au/book or call us on (07) 3062 2377.
Frequently Asked Questions
Why is my fridge running non-stop?
A fridge runs constantly when it cannot reach its target temperature. The most common causes are dirty condenser coils, faulty door seals, an incorrect thermostat setting, failed fan motors, defrost system faults, or low refrigerant. Brisbane’s warm climate means fridges naturally work harder, but continuous running without cycling off is not normal.
Is it dangerous if my fridge runs all the time?
Not immediately dangerous, but it significantly increases electricity costs, accelerates compressor wear, and usually indicates an underlying problem that will worsen. A fridge running constantly can use two to three times its normal energy consumption.
How much electricity does a constantly running fridge use?
A fridge running non-stop can consume 700 to 1000 kWh per year instead of the typical 300 to 400 kWh, adding $100 to $200 to your annual electricity bill at current Brisbane rates. Fixing the underlying cause typically pays for itself within one to two billing cycles.
Should I repair or replace a fridge that runs constantly?
If the fridge is under 10 years old and the issue is a seal, fan, thermostat, or defrost component, repair is almost always worthwhile — these parts cost a fraction of a new fridge. If the compressor has failed on a fridge over 12 years old, replacement is often more cost-effective. Our technicians can assess this honestly during a callout.
Energy Rating (Australian Government) provides efficiency comparisons if you decide to replace your fridge.