What Does It Cost to Change from Evaporative to Refrigerated Cooling?

The changeover from evaporative to refrigerated cooling is one of those jobs where the honest answer to "what does it cost" is a range rather than a number, and the range is wide enough to be genuinely unhelpful unless someone explains what moves it. So here is the breakdown.

Across Australia, a fully installed ducted refrigerated system generally runs between $9,000 and $18,000. Most three to four bedroom homes land in the $9,000 to $14,000 band. Complex retrofits can push past $20,000. A changeover sits toward the harder end of that spread by definition, because you are retrofitting into an occupied, finished house rather than installing into an open frame during construction.

For comparison, replacing an evaporative system like-for-like generally runs about $3,000 to $6,000 for a typical home. That gap is large enough that it is worth being certain the changeover is what you actually want before you price one.

The four things that actually move the price

**How much ductwork survives assessment.** This is the biggest single variable and the reason a genuine quote requires someone in your roof space. Evaporative systems move a large volume of air at low pressure, so their ducting tends to be a larger diameter and lighter grade than a refrigerated system wants. Some runs can often be retained. Outlets and returns almost always need work, because evaporative pushes air in and lets it escape, while refrigerated needs a sealed house and a proper return path.

**The capacity your house genuinely needs.** Sizing is not a per-square-metre calculation. Ceiling heights, how much glazing there is and which way it faces, insulation quality and the layout of living areas all feed into it. Getting this wrong by one capacity step is the difference between a system that cycles comfortably through a heatwave and one that runs flat out and never quite catches up.

**Zoning.** Dampers, a controller and the commissioning time to balance it properly all add cost. On a larger home with a separate bedroom wing it usually repays itself in running cost within a few summers. On a compact open-plan home it often does not, and you should be told that rather than sold it.

**Switchboard and electrical work.** Refrigerated systems draw considerably more than an evaporative unit. Some older boards need a dedicated circuit added or an upgrade before a system can be connected compliantly. This is a common reason an older home prices above an equivalent newer one.

What should be included and sometimes is not

Watch for three items when comparing quotes. Removal and disposal of the old evaporative unit. Capping the water supply. And properly closing the roof penetration — tiles replaced and re-bedded, or metal roofing patched and flashed.

That last one gets rushed more often than it should, and a poor patch does not announce itself immediately. It shows up as a leak in the first solid autumn rain, several months after everyone has moved on. Ask explicitly whether making the roof good is in the scope.

Why phone quotes are unreliable

Every variable above requires someone to look. A figure quoted from an address and a bedroom count is an estimate dressed up as a price, and the gap between it and the final invoice is where the arguments happen. A fixed price after an inspection is worth more than a cheap number over the phone, because it is the one you can actually hold someone to.