Aircon before summer: service, repair or replace?

A service costs $100–$320 per unit and takes an hour. A repair runs $150–$1,200 depending on the fault. A new split system is $1,200–$5,500 installed. The rule most technicians use: if the unit is over 10 years old and the repair quote is more than half the price of a new one, replace it. Do any of this in October or November, because by the first heatwave every installer in your city is booked out.

Service: what you get for $100–$320

A proper service is more than a filter rinse. The technician cleans the indoor coil and filters, flushes the drain, checks refrigerant pressure, tests the electrics and cleans the outdoor unit. A clogged indoor coil is the usual reason a unit that "still works" takes all afternoon to cool a room and costs more to run. If your unit is under 10 years old and simply underperforming, start here.

Book it now. Technicians fill their diaries in late November, and a service in a heatwave is either unavailable or priced like an emergency.

Repair: when it's worth fixing

Common faults and what they tend to cost:

• Not turning on, tripping the breaker, remote dead: usually a capacitor, sensor or control board. $150–$500.
• Blowing air but not cold: often low refrigerant from a leak. A regas without finding the leak is a short-term fix; the proper job is $300–$1,200.
• Water dripping inside: blocked drain or a failed pump. Often covered by a service; a pump replacement sits at the low end of the repair range.
• Loud outdoor unit: fan motor or compressor mounts. Fan motors are a minor repair; a failed compressor on an old unit is a replacement conversation.

Ask for the repair quote in writing and compare it with a new unit of the same size. Over half the price of new, on a unit past 10 years, is the point where most technicians will tell you to replace.

Replace: picking the right size

Oversized units short-cycle and never dehumidify; undersized ones run flat out. As a rough guide for a standard-height room: 2.5 kW for a bedroom up to 20 m², 3.5 kW for a large bedroom or study, 5 kW for a 30–40 m² living area, 7 kW for an open-plan space up to 60 m². North and west-facing rooms with big windows need the next size up. A good installer will measure rather than guess.

Running cost matters as much as the sticker: a 5 kW split costs $200–$350 a summer to run, a 7 kW unit $300–$500. A higher-efficiency unit costs more up front and less every year for 10–15 years.

What to ask your technician

• What is included in the service? Coil clean, drain flush and a refrigerant check should all be in the price.
• If it needs refrigerant, where is it leaking? A regas with no leak test is money you will spend again.
• What size do you recommend, and why? The answer should mention the room's size and orientation.
• Is removal of the old unit in the quote? It is $100–$350 and is often left off.
• What is the installation lead time? In November it may already be two to three weeks.