Air conditioners are no longer a luxury with most homes using these climate control systems to get through the hot Aussie summers.

But air conditioning systems also have a lifespan, beyond which their performance becomes unreliable and inefficient. Typical signs include delay in cooling the room, lower cooling efficiency, higher energy bills, more frequent service requirement and increased maintenance costs. Of course, regular servicing of your system will extend its life substantially but even a well-maintained air conditioner of a certain age might run into problems.

Daikin Australia has prepared a list of the Top 7 tell-tale signs that indicate you need to replace your air conditioner sooner than later. Call in a professional if you recognise any of these signs and see if repair is an option, or start shopping for a replacement unit.

1. Blowing hot or cold air inconsistent with temperature settings

When the unit begins to blow air – hot or cold – at temperatures inconsistent with the settings, it’s time to investigate. This may simply mean low refrigerant levels; however, warm air production at a cold setting can indicate a serious problem such as a damaged compressor.

So even if your air conditioner produces regular air levels, inconsistent temperatures may indicate serious trouble. When certain rooms become cold zones, and others don’t seem to get any cool air at all, it could mean the air conditioning unit is on the way out. When the unit produces hot air, inspect the filters, valves, condensation drains and coils for air flow obstructions. In any case, a replacement may be required.

2. Diminished air flow

A reduced air flow through the vents during operation could be a sign that the air conditioner’s compressor is on its last leg. If your thermostat is set to a reasonable temperature and your home is still too warm, then your air conditioning system is definitely not working at its optimum level. Again, check filters first, but it might be time for a new unit.

3. Strange noises or smells

A fully functioning air conditioning system should operate almost silently. Over a period of time, you will learn to recognise all the familiar little sounds. You’ll then know when the unit starts making strange noises that there may be something wrong with the unit. Minor noise changes could simply indicate the need for some repairs, for instance, a malfunctioning fan, a loose part or an internal mechanism becoming clogged with dirt. Louder noises such as screeching, grinding, grating, rattling, buzzing or ticking could indicate a serious problem that may require a unit replacement.

Similarly, if your unit is giving off a bad smell, it indicates a problem you need to address right away. Foul odours can mean that your air conditioner’s insulation has become damaged or that the ductwork has become mouldy. Dirt, mould or mildew inside your unit can circulate contaminated air through your home and cause health issues for your family. Never ever ignore bad or strange smells. However, check your filters first.

4. Your unit is leaking or producing excess moisture

Depending on the type of air conditioner, a small amount of condensation or water dripping can be expected on the outside of the unit. But for the most part, your air conditioning unit should stay dry whether or not it’s in use. If there’s moisture on the inside unit, a sudden increase in condensation or a leak, it may be time to replace the air conditioner. First, have a professional air conditioning technician inspect it straightaway for safety reasons. If the problem is traced to a refrigerant leak, the professional will handle it. Your air conditioning specialist will locate the source of the leak and let you know if a new unit is the most cost-effective course of action.

5. Your unit is short cycling

Air conditioners cycle on and off to maintain a set temperature throughout the home. However, when the unit tries to switch off randomly, or has difficulty getting started, it is possible that the system is malfunctioning. Short cycling puts extra stress on the air conditioner, and will lead to system failure if not handled quickly. A technician can tell you if it’s a blown fuse or time for a new unit.

6. Dramatic increase in energy bills

There are air conditioners that may appear to function normally but the homeowner ends up with an extremely high energy bill. Undertake an ‘energy audit’ and consider other factors that may have caused your energy bill to increase. This will help you work out whether your air conditioning is the culprit behind the surge in energy costs. If it is so, then you need to determine why it has become significantly less efficient. Perhaps your air conditioning system is overworking? Diminished cooling capacity will increase energy costs as your unit struggles to maintain the desired temperature ineffectively. Try cleaning the air vents and replacing the filters, and then check for any lumps or knots in the condensing coil. Of course, it may be an energy drain simply because it has become sluggish and is reaching the end of its working life.

7. Frequent repairs

At some point, you will realise that your trusty air conditioning unit has become more trouble (and expense) than it’s worth. In an ideal world, your unit should be serviced just once a year to keep it well maintained, clean and in top shape. An extra service or repair may occasionally be needed for some units.

However, if your air conditioning system is constantly in need of mending and repairing multiple times per year, then you may have to call time on it because replacing your air conditioner may simply be the more economical and efficient option. Servicing an old unit may result in more expense, and probably more issues. If your unit needs a complex repair after the warranty expires, that’s a sure sign to start shopping around for a new unit instead of pouring money into an old one with a limited shelf life.

If you detect any of these 7 signs that your air conditioning is malfunctioning, it’s time to call in a professional. To stay comfortable during the summer months, it’s vital to carry out any necessary repairs. Acting now will let you get back to enjoying a trouble-free, noise-free, leak-free, energy-efficient Aussie summer or winter.