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Get the story
When it stopped heating, whether cooling still works, how old the unit is. It all narrows the fault before we arrive.
We find why it's blowing cold and fix it properly. Sydney wide, since 1991.
Air Conditioner Not Heating?
Common AC Problems
Why Your Air Conditioner
Isn't Heating Properly
Reverse cycle blowing cold air in winter? It's usually one of these. The system sitting in defrost mode, which is normal, give it ten minutes. A failed reversing valve or its solenoid, so it can't switch from cooling to heating. Low gas from a leak, which hurts heating exactly like it hurts cooling. Or a packed filter choking the airflow.
If the outdoor unit is steaming or paused with the fan off on a cold morning, that's defrost doing its job. If it never warms up at all, that's a fault, and it needs a tech.
We see reverse cycle not heating calls every winter, and most of them are cheaper to fix than people fear. A service call to find the fault is $250 plus GST, covering attendance and diagnosis. From there we quote the repair before we touch it. Labour's $125 an hour where it applies. A gas top-up runs $200 to $350, a sensor or solenoid swap usually $250 to $350 fitted. Full rundown on our pricing page.
Same machine does both jobs, so the same faults that stop cooling stop heating too. If yours also struggled last summer, have a read of our not cooling page. Since 1991, 4.8 stars from 280+ reviews.
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Years of Industry Experience
Licensed, Certified & Insured Technicians
Environmentally Responsible & ARCtick Certified
100% Service Satisfaction Guarantee
Flexible & Affordable Financing Options
Wide Range of Systems & Leading Brands
Quick Checks First
Before You Book a Service
1. Check the mode
Make sure it's on Heat, not Auto or Cool, and the set temp is a few degrees above the room. Half the no-heat calls we get in June are a remote set wrong.
2. Give it ten minutes
On frosty mornings the outdoor unit stops to defrost itself. Steam coming off it is normal. Let it finish before you decide it's broken.
3. Bump the fan speed
Low fan on a big room spreads the heat too thin. Put it on medium or high and let it push the warm air down to floor level.
4. Wash the filter
A packed filter chokes heating the same as cooling. Pull the filters, rinse them under the tap, let them dry and pop them back.
5. Shut the doors
Heating an open-plan space with the hallway doors open is heating the whole house. Close off what you're not using and the room warms twice as fast.
If the System Is Still Not Heating
A reverse cycle air conditioner is a fridge running backwards. It pulls heat out of the cold air outside and pumps it into your room. When it can't do that, the cause is nearly always one of four things, and none of them fix themselves.
The reversing valve is the part that flips the system between cooling and heating. When it sticks, or the little solenoid coil that drives it dies, you get cold air in heating mode and a unit that seems fine in summer. The solenoid is a quick swap, usually $250 to $350 fitted. A seized valve itself is a bigger job, and we'll quote it straight before you commit to anything.
Low gas is the sneaky one. The system is sealed, so if the gas is low it's leaked, and a low system can't move heat in either direction. You'll often notice it as weak heating in winter after a summer of so-so cooling. We pressure test, find the leak, fix it and regas. A straight top-up runs $200 to $350.
Then there's sizing. A unit that's too small keeps up fine in spring and falls over on a 5 degree morning. No repair fixes undersizing. Before you blame the machine, run your room through our sizing calculator and see what the space actually needs.
Frost on the outdoor unit in winter is normal during defrost. A solid block of ice that never clears is not. If yours is icing up, don't chip at it, read our ice on the unit page and give us a bell on (02) 9820 4500.
Common Factors
Common Heating Problems
Here's what we actually find on no-heat jobs across Sydney, roughly most common first, and what each one costs to put right. If yours doesn't fit, ring us and describe it.
System blowing cold air
Either the system is mid-defrost, which is normal and passes in ten minutes, or the reversing valve isn’t switching over. A failed solenoid coil is the usual culprit and runs $250 to $350 fitted. A stuck valve is quoted before we start.
System takes a long time to heat
Usually low gas. The unit works, just slowly, because there isn’t enough refrigerant to carry the heat. We find the leak, repair it and regas. Top-ups run $200 to $350, leak repairs quoted on top.
Weak or uneven heating
Packed filters, a low fan speed, or a system too small for the space on cold mornings. Filters are a free fix. If it’s sizing, no repair helps, check our sizing calculator before spending a dollar.
Intermittent heating
Heating that cuts in and out is often a faulty temperature sensor confusing the defrost logic, so the unit defrosts when it shouldn’t. Sensors are cheap, usually $250 to $350 fitted. A failing PC board does the same thing and runs $400 to $700.
When to Stop Using Your Heating System
Most heating faults are an inconvenience, not a danger, but a few mean stop. A burning smell on the first cold morning of the year is usually dust burning off the heat exchanger and clears in ten minutes with a window open. If it doesn't clear, or it smells electrical, switch the system off at the breaker and call us. If the breaker trips when the heating kicks in, stop resetting it, something is shorting and every reset cooks it further. And if the outdoor unit has turned into a block of solid ice that never clears, don't chip at it, switch the unit off and get it looked at before the compressor pays the price.
Diagnosis Process
How We Find a Heating Fault
No guesswork and no parts roulette. Here's how a no-heat job runs from your call to a warm room.
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Test it in both modes
Cooling fine but no heat points straight at the reversing valve. Weak in both modes points at gas or airflow.
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Gauges on
Refrigerant pressures in heating mode tell us in minutes whether the system is low on gas.
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Check the reversing valve
We energise the solenoid and listen for the valve shifting. A dead coil or a stuck valve shows up straight away.
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Test sensors and defrost logic
A drifting temperature sensor makes the unit defrost constantly. We check the readings against actuals.
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Quote, then fix
You get the price before we start. Most heating fixes are done the same visit, parts permitting.
Real Jobs
Heating Jobs We've Fixed
Actron ducted, cold air in heating mode – Quakers Hill
Cooling worked all summer, switched to heat in May and got cold air out of every vent. Reversing valve solenoid coil had died. Energised it, confirmed no shift, fitted a new coil and retested both modes. $320.
Daikin split, weak heating – Ashfield
7.1kW Daikin in a semi, taking hours to warm the lounge. Pressures were low. Found a weeping flare at the outdoor unit, re-flared it, pressure tested and regassed with R32. Heating back to full the same visit. $360.
Panasonic split, kept stopping to defrost – Penshurst
Unit defrosting every fifteen minutes on a mild day, barely any heat making it inside. Outdoor coil sensor had drifted way out. New sensor fitted, defrost logic back to normal. $260.
Cold House? Sorted.
Give us a bell on (02) 9820 4500 before the next cold snap. Family run since 1991, licensed (NSW 273312C), ARCtick certified (AU13058), 4.8 stars from 280+ reviews. Monday to Friday 7am-5pm, Saturdays by arrangement. We quote before we fix, and most heating jobs are done the same visit.
FAQS
Air Conditioning Not Heating - Your Questions
Either it’s mid-defrost, which is normal and passes in about ten minutes, or the reversing valve isn’t switching the system into heating. If cooling works but heating never comes, it’s the valve or its solenoid. That’s a tech job, usually $250 to $350 fitted for the coil.
Four free things. The remote is on Heat with the temp set above the room. The filters are clean. The fan speed is medium or high. And the outdoor unit isn’t mid-defrost, give it ten minutes. If it still blows cold after that, ring us.
Yeah, same as it stops cooling. A packed filter chokes the airflow so the warm air never makes it into the room. Wash the filters under the tap, dry them, and you’ve fixed it for free more often than you’d think.
A service call to find the fault is $250 plus GST. From there we quote before we start. A reversing valve solenoid or sensor is usually $250 to $350 fitted, a gas top-up $200 to $350, a PC board $400 to $700. Most are done same visit.
Defrost cycles. On cold mornings the outdoor coil frosts up and the unit pauses heating to melt it off. A few minutes every hour or so is normal. Defrosting every ten minutes on a mild day means a sensor fault, and that’s worth a call.
Light frost that comes and goes is normal defrost behaviour. A solid block of ice that never melts means the defrost system has failed or the gas is low. Don’t chip at it. Switch the unit off and get it looked at before the compressor cops it.
Generally yes, it’s the cheapest way to heat a Sydney home per unit of warmth. But a struggling system loses that edge fast. If yours runs flat out for small heat, a $250 service often pays for itself inside one winter.
On ducted systems that’s usually a zone damper stuck shut or a duct that’s come loose in the roof. On splits it’s often just fan speed and closed doors. Dampers and duct repairs are quoted after we’ve had a look in the roof.
Jay’s Air. Family run since 1991, our own blokes not subbies, fixed pricing and no surprises. Licensed (NSW 273312C), ARCtick certified (AU13058), 4.8 stars from 280+ reviews. Give us a bell on (02) 9820 4500.